I need a Video lecture PPT for the below mentioned topic.

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timer Asked: Dec 26th, 2018
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Question description

I need a Video lecture PPT for the below mentioned topic. Please include explanation for each slide in voice and I will later make a video and add it to the PPT. I need the lecture Video not more than 10 mins.

1. Study Chapters 9 and 10 (Monopoly and Market Power).

2. Prepare a lecture note video in power point:

A. Include your picture in your video. Video without your picture will not be graded.

B. Your video should be limited to no more than 10 minutes

C. Include at least one solved problem in your video. Provide explanations of the problem you solved and discuss how you would apply the concepts in managerial decision making.

NOTE: PART C IS VERY IMPORTANT AND I HAVE ATTACHED THE TEXT BOOK. I AM ATTACHING AN EXAMPLE PPT AS WELL.


Managerial Economics and Strategy THE P E ARS O N S ER IES IN EC ON OM IC S Abel/Bernanke/Croushore Macroeconomics* Froyen Macroeconomics Bade/Parkin Foundations of Economics* Fusfeld The Age of the Economist Berck/Helfand The Economics of the Environment Gerber International Economics* Laidler The Demand for Money Leeds/von Allmen The Economics of Sports Leeds/von Allmen/Schiming Economics* Lipsey/Ragan/Storer Economics* Lynn Economic Development: Theory and Practice for a Divided World Miller Economics Today* Understanding Modern Economics Miller/Benjamin The Economics of Macro Issues Miller/Benjamin/North The Economics of Public Issues Mills/Hamilton Urban Economics González-Rivera Forecasting for Economics and Business Bierman/Fernandez Game Theory with Economic Applications Gordon Macroeconomics* Blanchard Macroeconomics* Greene Econometric Analysis Blau/Ferber/Winkler The Economics of Women, Men, and Work Gregory Essentials of Economics Boardman/Greenberg/ Vining/ Weimer Cost-Benefit Analysis Gregory/Stuart Russian and Soviet Economic Performance and Structure Boyer Principles of Transportation Economics Hartwick/Olewiler The Economics of Natural Resource Use Branson Macroeconomic Theory and Policy Heilbroner/Milberg The Making of the Economic Society Brock/Adams The Structure of American Industry Heyne/Boettke/Prychitko The Economic Way of Thinking Bruce Public Finance and the American Economy Carlton/Perloff Modern Industrial Organization Caves/Frankel/Jones World Trade and Payments: An Introduction Cooter/Ulen Law & Economics Downs An Economic Theory of Democracy Folland/Goodman/Stano The Economics of Health and Health Care Fort Sports Economics Nafziger The Economics of Developing Countries O’Sullivan/Sheffrin/Perez Economics: Principles, Applications and Tools* Hubbard/O’Brien/Rafferty Macroeconomics* Chapman Environmental Economics: Theory, Application, and Policy Farnham Economics for Managers Murray Econometrics: A Modern Introduction Holt Markets, Games, and Strategic Behavior Hubbard/O’Brien Economics* Money, Banking, and the Financial System* Case/Fair/Oster Principles of Economics* Ehrenberg/Smith Modern Labor Economics Hoffman/Averett Women and the Economy: Family, Work, and Pay Mishkin The Economics of Money, Banking, and Financial Markets* The Economics of Money, Banking, and Financial Markets, Business School Edition* Macroeconomics: Policy and Practice* Parkin Economics* Hughes/Cain American Economic History Husted/Melvin International Economics Jehle/Reny Advanced Microeconomic Theory Perloff Microeconomics* Microeconomics: Theory and Applications with Calculus* Johnson-Lans A Health Economics Primer Perloff/Brander Managerial Economics and Strategy* Keat/Young/Erfle Managerial Economics Phelps Health Economics Klein Mathematical Methods for Economics Pindyck/Rubinfeld Microeconomics* Krugman/Obstfeld/Melitz International Economics: Theory & Policy* *denotes MyEconLab titles Riddell/Shackelford/Stamos/ Schneider Economics: A Tool for Critically Understanding Society Ritter/Silber/Udell Principles of Money, Banking & Financial Markets* Roberts The Choice: A Fable of Free Trade and Protection Rohlf Introduction to Economic Reasoning Ruffin/Gregory Principles of Economics Sargent Rational Expectations and Inflation Sawyer/Sprinkle International Economics Scherer Industry Structure, Strategy, and Public Policy Schiller The Economics of Poverty and Discrimination Sherman Market Regulation Silberberg Principles of Microeconomics Stock/Watson Introduction to Econometrics Studenmund Using Econometrics: A Practical Guide Tietenberg/Lewis Environmental and Natural Resource Economics Environmental Economics and Policy Todaro/Smith Economic Development Waldman Microeconomics Waldman/Jensen Industrial Organization: Theory and Practice Walters/Walters/Appel/ Callahan/Centanni/Maex/ O’Neill Econversations: Today’s Students Discuss Today’s Issues Weil Economic Growth Williamson Macroeconomics Visit www.myeconlab.com to learn more. Managerial Economics and Strategy Jeffrey M. Perloff University of California, Berkeley James A. Brander Sauder School of Business, University of British Columbia Boston Columbus Indianapolis New York San Francisco Upper Saddle River Amsterdam Cape Town Dubai London Madrid Milan Munich Paris Montreal Toronto Delhi Mexico City Sao Paulo Sydney Hong Kong Seoul Singapore Taipei Tokyo For Jackie, Lisa, Barbara, and Cathy Editor-in-Chief: Donna Battista Executive Acquisitions Editor: Adrienne D’Ambrosio Editorial Project Manager: Sarah Dumouchelle Editorial Assistant: Elissa Senra-Sargent Executive Marketing Manager: Lori DeShazo Managing Editor: Jeff Holcomb Senior Production Project Manager: Meredith Gertz Senior Procurement Specialist: Carol Melville Art Director: Jonathan Boylan Cover Designer: John Christiana Cover Image: Artisilense/Shutterstock Image Manager: Rachel Youdelman Photo Research: Integra Software Services, Ltd. Associate Project Manager—Text Permissions: Samantha Blair Graham Text Permissions Research: Electronic Publishing Services Director of Media: Susan Schoenberg Content Leads, MyEconLab: Noel Lotz and Courtney Kamauf Executive Media Producer: Melissa Honig Project Management and Text Design: Gillian Hall, The Aardvark Group Composition and Illustrations: Laserwords Maine Copyeditor: Rebecca Greenberg Proofreader: Holly McLean-Aldis Indexer: John Lewis Printer/Binder: RR Donnelley Cover Printer: Lehigh Phoenix Text Font: Palatino Credits and acknowledgments borrowed from other sources and reproduced, with permission, in this textbook appear on the appropriate page within text or on page E-51. Copyright © 2014 by Pearson Education, Inc. All rights reserved. Manufactured in the United States of America. This publication is protected by Copyright, and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. To obtain permission(s) to use material from this work, please submit a written request to Pearson Education, Inc., Permissions Department, One Lake Street, Upper Saddle River, New Jersey 07458, or you may fax your request to 201-236-3290. Many of the designations by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and the publisher was aware of a trademark claim, the designations have been printed in initial caps or all caps. Library of Congress Cataloging-in-Publication Data Perloff, Jeffrey M. Managerial economics and strategy/Jeffrey Perloff, James Brander. — First edition. pages cm Includes bibliographical references and index. ISBN 978-0-321-56644-7 1. Managerial economics. I. Brander, James A. II. Title. HD30.22.P436 2014 338.5024’658 — dc23 2013022387 10 9 8 7 6 5 4 3 2 1 www.pearsonhighered.com ISBN 10: 0-321-56644-0 ISBN 13: 978-0-321-56644-7 Brief Contents Preface xiii Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Introduction 1 Supply and Demand 7 Empirical Methods for Demand Analysis 42 Consumer Choice 85 Production 124 Costs 154 Firm Organization and Market Structure 193 Competitive Firms and Markets 232 Monopoly 273 Pricing with Market Power 311 Oligopoly and Monopolistic Competition 354 Game Theory and Business Strategy 389 Strategies over Time 428 Managerial Decision Making Under Uncertainty 464 Asymmetric Information 500 Government and Business 533 Global Business 573 Answers to Selected Questions E-1 Definitions E-13 References E-18 Sources for Managerial Problems, Mini-Cases, and Managerial Implications E-24 Index E-32 Credits E-51 v Contents Preface Chapter 1 Introduction 1.1 Managerial Decision Making Profit Trade-Offs Other Decision Makers Strategy 1.2 Economic Models MINI-CASE Using an Income Threshold Model in China Simplifying Assumptions Testing Theories Positive and Normative Statements Summary Chapter 2 Supply and Demand MANAGERIAL PROBLEM Carbon Taxes 2.1 Demand The Demand Curve The Demand Function USING CALCULUS Deriving the Slope of a Demand Curve Summing Demand Curves MINI-CASE Aggregating the Demand for Broadband Service 2.2 Supply The Supply Curve The Supply Function Summing Supply Curves 2.3 Market Equilibrium Using a Graph to Determine the Equilibrium Using Algebra to Determine the Equilibrium Forces That Drive the Market to Equilibrium 2.4 Shocks to the Equilibrium Effects of a Shift in the Demand Curve Effects of a Shift in the Supply Curve Q&A 2.1 MANAGERIAL IMPLICATION Taking Advantage of Future Shocks Effects of Shifts in Both Supply and Demand Curves MINI-CASE Genetically Modified Foods Q&A 2.2 vi xiii 1 1 2 2 3 3 3 4 4 5 5 6 7 7 9 10 13 14 14 15 15 16 17 18 18 18 19 20 21 21 21 22 23 24 24 25 2.5 Effects of Government Interventions Policies That Shift Curves MINI-CASE Occupational Licensing Price Controls MINI-CASE Disastrous Price Controls Sales Taxes Q&A 2.3 MANAGERIAL IMPLICATION Cost Pass- 26 26 26 27 29 31 33 Through 34 2.6 When to Use the Supply-and-Demand Model 34 MANAGERIAL SOLUTION Carbon Taxes 36 Summary 37 ■ Questions 38 Chapter 3 Empirical Methods for Demand Analysis 42 MANAGERIAL PROBLEM Estimating the Effect of an iTunes Price Change 3.1 Elasticity The Price Elasticity of Demand MANAGERIAL IMPLICATION Changing Prices to Calculate an Arc Elasticity Q&A 3.1 USING CALCULUS The Point Elasticity of Demand Q&A 3.2 Elasticity Along the Demand Curve Other Demand Elasticities MINI-CASE Substitution May Save Endangered Species Demand Elasticities over Time Other Elasticities Estimating Demand Elasticities MINI-CASE Turning Off the Faucet 3.2 Regression Analysis A Demand Function Example MINI-CASE The Portland Fish Exchange Multivariate Regression Q&A 3.3 Goodness of Fit and the R2 Statistic MANAGERIAL IMPLICATION Focus Groups 3.3 Properties and Statistical Significance of Estimated Coefficients Repeated Samples Desirable Properties for Estimated Coefficients A Focus Group Example Confidence Intervals 42 43 44 45 45 47 47 47 50 51 52 52 52 53 53 54 55 60 61 61 62 63 63 63 64 65 Contents Hypothesis Testing and Statistical Significance 3.4 Regression Specification Selecting Explanatory Variables MINI-CASE Determinants of CEO Compensation Q&A 3.4 Functional Form MANAGERIAL IMPLICATION Experiments 3.5 Forecasting Extrapolation Theory-Based Econometric Forecasting MANAGERIAL SOLUTION Estimating the Effect of an iTunes Price Change Summary 80 ■ Questions 81 Appendix 3 The Excel Regression Tool Chapter 4 Consumer Choice MINI-CASE How You Ask the Question Matters 66 67 67 67 69 71 73 74 74 76 77 84 85 MANAGERIAL PROBLEM Paying Employees to Relocate 4.1 Consumer Preferences Properties of Consumer Preferences MINI-CASE You Can’t Have Too Much Money Preference Maps 4.2 Utility Utility Functions Ordinal and Cardinal Utility Marginal Utility USING CALCULUS Marginal Utility Marginal Rates of Substitution 4.3 The Budget Constraint Slope of the Budget Line USING CALCULUS The Marginal Rate of Transformation Effects of a Change in Price on the Opportunity Set Effects of a Change in Income on the Opportunity Set Q&A 4.1 MINI-CASE Rationing Q&A 4.2 4.4 Constrained Consumer Choice The Consumer’s Optimal Bundle Q&A 4.3 MINI-CASE Why Americans Buy More E-Books Than Do Germans Q&A 4.4 Promotions 85 87 87 88 89 95 95 96 96 97 98 98 100 101 Consumer Choices to Relocate Summary 118 ■ Questions 119 Appendix 4A The Marginal Rate of Substitution Appendix 4B The Consumer Optimum Chapter 5 Production 116 122 122 124 MANAGERIAL PROBLEM Labor Productivity During Recessions 5.1 Production Functions 5.2 Short-Run Production The Total Product Function The Marginal Product of Labor USING CALCULUS Calculating the Marginal Product of Labor Q&A 5.1 The Average Product of Labor Graphing the Product Curves The Law of Diminishing Marginal Returns MINI-CASE Malthus and the Green Revolution 5.3 Long-Run Production Isoquants MINI-CASE A Semiconductor Isoquant Substituting Inputs Q&A 5.2 USING CALCULUS Cobb-Douglas Marginal Products 5.4 Returns to Scale Constant, Increasing, and Decreasing Returns to Scale 102 102 102 102 103 103 105 Manufacturing Varying Returns to Scale 110 110 113 113 113 116 MANAGERIAL SOLUTION Paying Employees Q&A 5.3 MINI-CASE Returns to Scale in U.S. 106 107 108 114 115 MANAGERIAL IMPLICATION Simplifying 101 MANAGERIAL IMPLICATION Designing Promotions 4.5 Deriving Demand Curves 4.6 Behavioral Economics Tests of Transitivity Endowment Effects Salience vii MANAGERIAL IMPLICATION Small Is Beautiful 5.5 Productivity and Technological Change Relative Productivity MINI-CASE U.S. Electric Generation Efficiency Innovation MINI-CASE Tata Nano’s Technical and Organizational Innovations MANAGERIAL SOLUTION Labor Productivity During Recessions Summary 150 ■ Questions 151 Chapter 6 Costs 124 125 127 127 128 128 129 129 129 132 133 134 134 137 138 139 141 141 141 143 143 145 146 146 146 147 147 148 149 154 MANAGERIAL PROBLEM Technology Choice at Home Versus Abroad 154 viii Contents 6.1 The Nature of Costs Opportunity Costs MINI-CASE The Opportunity Cost of an MBA Q&A 6.1 Costs of Durable Inputs Sunk Costs 155 155 156 157 157 158 MANAGERIAL IMPLICATION Ignoring Sunk Costs 6.2 Short-Run Costs Common Measures of Cost USING CALCULUS Calculating Marginal Cost Cost Curves Production Functions and the Shapes of Cost Curves USING CALCULUS Calculating Cost Curves Short-Run Cost Summary 6.3 Long-Run Costs Input Choice MANAGERIAL IMPLICATION Cost Minimization by Trial and Error MINI-CASE The Internet and Outsourcing Q&A 6.2 The Shapes of Long-Run Cost Curves MINI-CASE Economies of Scale in Nuclear Power Plants Q&A 6.3 Long-Run Average Cost as the Envelope of Short-Run Average Cost Curves MINI-CASE Long-Run Cost Curves in Beer Manufacturing and Oil Pipelines 6.4 The Learning Curve MINI-CASE Learning by Drilling 6.5 The Costs of Producing Multiple Goods MINI-CASE Scope MANAGERIAL SOLUTION Technology Choice at Home Versus Abroad Summary 187 ■ Questions 187 Appendix 6 Long-Run Cost Minimization 159 159 159 161 161 163 166 167 168 168 173 174 175 176 178 179 180 181 182 183 184 185 185 192 Chapter 7 Firm Organization and Market Structure 193 MANAGERIAL PROBLEM Clawing Back Bonuses 7.1 Ownership and Governance of Firms Private, Public, and Nonprofit Firms MINI-CASE Chinese State-Owned Enterprises Ownership of For-Profit Firms Firm Governance 7.2 Profit Maximization Profit Two Steps to Maximizing Profit USING CALCULUS Maximizing Profit Q&A 7.1 MANAGERIAL IMPLICATION Marginal Decision Making 193 195 195 197 197 199 199 199 200 201 202 202 Profit over Time 204 MANAGERIAL IMPLICATION Stock Prices Versus Profit 7.3 Owners’ Versus Managers’ Objectives Consistent Objectives Q&A 7.2 Conflicting Objectives Q&A 7.3 MINI-CASE Company Jets Monitoring and Controlling a Manager’s Actions Takeovers and the Market for Corporate Control MINI-CASE The Yahoo! Poison Pill 7.4 The Make or Buy Decision Stages of Production Vertical Integration Profitability and the Supply Chain Decision MINI-CASE Vertical Integration at American Apparel MINI-CASE Aluminum Market Size and the Life Cycle of a Firm 7.5 Market Structure The Four Main Market Structures Comparison of Market Structures Road Map to the Rest of the Book MANAGERIAL SOLUTION Clawing Back Bonuses Summary 226 ■ Questions 227 Appendix 7 Interest Rates, Present Value, and Future Value 204 205 205 207 208 209 210 211 212 214 214 215 215 217 218 219 221 222 222 224 224 225 230 Chapter 8 Competitive Firms and Markets 232 MANAGERIAL PROBLEM The Rising Cost of Keeping On Truckin’ 8.1 Perfect Competition Characteristics of a Perfectly Competitive Market Deviations from Perfect Competition 8.2 Competition in the Short Run How Much to Produce Q&A 8.1 USING CALCULUS Profit Maximization with a Specific Tax Whether to Produce MINI-CASE Oil, Oil Sands, and Oil Shale Shutdowns The Short-Run Firm Supply Curve The Short-Run Market Supply Curve Short-Run Competitive Equilibrium 8.3 Competition in the Long Run Long-Run Competitive Profit Maximization The Long-Run Firm Supply Curve MINI-CASE The Size of Ethanol Processing Plants 232 233 234 235 236 236 239 240 240 242 243 244 246 247 247 248 248 Contents The Long-Run Market Supply Curve MINI-CASE Fast-Food Firms’ Entry in Russia MINI-CASE Upward-Sloping Long-Run Supply Curve for Cotton Long-Run Competitive Equilibrium Zero Long-Run Profit with Free Entry 8.4 Competition Maximizes Economic Well-Being Consumer Surplus MANAGERIAL IMPLICATION Willingness to Pay on eBay Producer Surplus Q&A 8.2 Q&A 8.3 Competition Maximizes Total Surplus MINI-CASE The Deadweight Loss of Christmas Presents Effects of Government Intervention Q&A 8.4 MANAGERIAL SOLUTION The Rising Cost of Keeping On Truckin’ Summary 268 ■ Questions 248 249 251 252 254 254 255 257 258 260 261 262 264 265 266 267 269 Chapter 9 Monopoly 273 MANAGERIAL PROBLEM Brand-Name and Generic Drugs 9.1 Monopoly Profit Maximization Marginal Revenue USING CALCULUS Deriving a Monopoly’s Marginal Revenue Function Q&A 9.1 Choosing Price or Quantity Two Steps to Maximizing Profit USING CALCULUS Solving for the ProfitMaximizing Output Effects of a Shift of the Demand Curve 9.2 Market Power Market Power and the Shape of the Demand Curve MANAGERIAL IMPLICATION Checking Whether the Firm Is Maximizing Profit MINI-CASE Cable Cars and Profit Maximization The Lerner Index MINI-CASE Apple’s iPad Q&A 9.2 Sources of Market Power 9.3 Market Failure Due to Monopoly Pricing Q&A 9.3 9.4 Causes of Monopoly Cost-Based Monopoly Q&A 9.4 Government Creation of Monopoly MINI-CASE Botox 273 275 275 278 279 280 281 283 283 285 285 286 286 287 288 289 289 9.5 Advertising Deciding Whether to Advertise How Much to Advertise USING CALCULUS Optimal Advertising Q&A 9.5 MINI-CASE Super Bowl Commercials 9.6 Networks, Dynamics, and Behavioral Economics Network Externalities Network Externalities and Behavioral Economics Network Externalities as an Explanation for Monopolies MINI-CASE Critical Mass and eBay MANAGERIAL IMPLICATION Introductory Prices MANAGERIAL SOLUTION Brand-Name and Generic Drugs Summary 307 ■ Questions 307 Chapter 10 Pricing with Market Power MANAGERIAL PROBLEM Sale Prices 10.1 Conditions for Price Discrimination Why Price Discrimination Pays MINI-CASE Disneyland Pricing Which Firms Can Price Discriminate MANAGERIAL IMPLICATION Preventing Resale MINI-CASE Preventing Resale of Designer Bags Not All Price Differences Are Price Discrimination Types of Price Discrimination 10.2 Perfect Price Discrimination How a Firm Perfectly Price Discriminates Perfect Price Discrimination Is Efficient but Harms Some Consumers MINI-CASE Botox Revisited Q&A 10.1 Individual Price Discrimination MINI-CASE Dynamic Pricing at Amazon 10.3 Group Price Discrimination Group Price Discrimination with Two Groups USING CALCULUS Maximizing Profit for a Group Discriminating Monopoly MINI-CASE Reselling Textbooks Q&A 10.2 Identifying Groups MANAGERIAL IMPLICATION Discounts 290 292 293 294 295 296 297 Effects of Group Price Discrimination on Total Surplus 10.4 Nonlinear Price Discrimination 10.5 Two-Part Pricing Two-Part Pricing with Identical Consumers Two-Part Pricing with Differing Consumers MINI-CASE Available for a Song ix 298 299 299 300 301 301 302 302 303 304 304 305 305 311 311 313 313 315 315 316 317 317 318 318 318 319 321 322 323 324 324 325 326 328 328 330 331 332 333 335 335 337 338 x Contents 10.6 Bundling Pure Bundling Mixed Bundling Q&A 10.3 Requirement Tie-In Sales MANAGERIAL IMPLICATION Ties That Bind 10.7 Peak-Load Pricing MINI-CASE Downhill Pricing MANAGERIAL SOLUTION Sale Prices Summary 348 ■ Questions 349 339 340 341 343 344 344 344 346 347 354 MANAGERIAL PROBLEM Gaining an Edge from Government Aircraft Subsidies 11.1 Cartels Why Cartels Succeed or Fail MINI-CASE A Catwalk Cartel Maintaining Cartels 11.2 Cournot Oligopoly Airlines USING CALCULUS Deriving a Cournot Firm’s Marginal Revenue The Number of Firms MINI-CASE Air Ticket Prices and Rivalry Nonidentical Firms Q&A 11.1 Q&A 11.2 MANAGERIAL IMPLICATION Differentiating a Product Through Marketing Mergers MINI-CASE Acquiring Versus Merging 11.3 Bertrand Oligopoly Identical Products Differentiated Products 11.4 Monopolistic Competition MANAGERIAL IMPLICATION Managing in the Monopolistically Competitive Food Truck Market Equilibrium Q&A 11.3 Profitable Monopolistically Competitive Firms MINI-CASE Zoning Laws as a Barrier to Entry by Hotel Chains MANAGERIAL SOLUTION Gaining an Edge from Government Aircraft Subsidies Summary 383 ■ Questions 383 Appendix 11A Cournot Oligopoly with Many Firms Appendix 11B Nash-Bertrand Equilibrium 354 356 356 358 359 360 361 365 366 366 368 369 371 372 372 374 374 375 376 378 378 379 380 380 381 381 386 387 MANAGERIAL PROBLEM Dying to Work 12.3 Information and Rationality Incomplete Information MANAGERIAL IMPLICATION Solving Coordination Problems Rationality MANAGERIAL IMPLICATION Using Game Theory to Make Business Decisions 12.4 Bargaining Bargaining Games The Nash Bargaining Solution Q&A 12.3 USING CALCULUS Maximizing the Nash Product MINI-CASE Nash Bargaining over Coffee Inefficiency in Bargaining 12.5 Auctions Elements of Auctions Bidding Strategies in Private-Value Auctions MINI-CASE Experienced Bidders MINI-CASE Google Advertising The Winner’s Curse MANAGERIAL IMPLICATION Auction Design MANAGERIAL SOLUTION Dying to Work Summary 421 ■ Questions 422 Appendix 12 Determining a Mixed Strategy Chapter 13 Strategies over Time 389 389 392 393 394 396 398 399 400 401 403 403 406 407 408 408 409 410 411 411 412 412 413 414 414 414 415 415 416 417 418 419 420 420 427 428 MANAGERIAL PROBLEM Intel and AMD’s Advertising Strategies 13.1 Repeated Games Strategies and Actions in Dynamic Games Cooperation in a Repeated Prisoner’s Dilemma Game MINI-CASE Tit-for-Tat Strategies in Trench Warfare Implicit Versus Explicit Collusion Finitely Repeated Games 13.2 Sequential Games Stackelberg Oligopoly Credible Threats Q&A 13.1 Chapter 12 Game Theory and Business Strategy Q&A 12.1 12.2 Types of Nash Equilibria Multiple Equilibria MINI-CASE Timing Radio Ads Mixed-Strategy Equilibria MINI-CASE Competing E-Book Formats Q&A 12.2 Chapter 11 Oligopoly and Monopolistic Competition 12.1 Oligopoly Games Dominant Strategies Best Responses Failure to Maximize Joint Profits MINI-CASE Strategic Advertising 13.3 Deterring Entry Exclusion Contracts MINI-CASE Pay-for-Delay Agreements 428 430 430 431 433 434 434 435 436 439 440 441 441 442 Contents Limit Pricing MINI-CASE Pfizer Uses Limit Pricing to Slow Entry Q&A 13.2 Entry Deterrence in a Repeated Game 13.4 Cost Strategies Investing to Lower Marginal Cost Learning by Doing Raising Rivals’ Costs Q&A 13.3 MINI-CASE Auto Union Negotiations 13.5 Disadvantages of Moving First The Holdup Problem MINI-CASE Venezuelan Nationalization MANAGERIAL IMPLICATION Avoiding Holdups Moving Too Quickly MINI-CASE Advantages and Disadvantages of Moving First 13.6 Behavioral Game Theory Ultimatum Games MINI-CASE GM’s Ultimatum Levels of Reasoning MANAGERIAL IMPLICATION Taking Advantage of Limited Strategic Thinking MANAGERIAL SOLUTION Intel and AMD’s Advertising Strategies Summary 458 ■ Questions 459 Appendix 13 A Mathematical Approach to Stackelberg Oligopoly 443 444 444 445 446 446 448 448 448 449 450 450 451 452 453 453 454 454 454 456 457 457 463 Chapter 14 Managerial Decision Making Under Uncertainty 464 MANAGERIAL PROBLEM Risk and Limited Liability 14.1 Assessing Risk Probability Expected Value Q&A 14.1 Variance and Standard Deviation MANAGERIAL IMPLICATION Summarizing Risk 14.2 Attitudes Toward Risk Expected Utility Risk Aversion Q&A 14.2 USING CALCULUS Diminishing Marginal Utility of Wealth MINI-CASE Stocks’ Risk Premium Risk Neutrality Risk Preference MINI-CASE Gambling Risk Attitudes of Managers 14.3 Reducing Risk Obtaining Information MINI-CASE Bond Ratings Diversification 464 466 466 467 469 469 470 471 471 472 474 474 475 475 476 476 478 478 479 479 480 xi MANAGERIAL IMPLICATION Diversifying Retirement Funds Insurance Q&A 14.3 MINI-CASE Limited Insurance for Natural Disasters 14.4 Investing Under Uncertainty Risk-Neutral Investing Risk-Averse Investing Q&A 14.4 14.5 Behavioral Economics and Uncertainty Biased Assessment of Probabilities MINI-CASE Biased Estimates Violations of Expected Utility Theory Prospect Theory MANAGERIAL SOLUTION Risk and Limited Liability Summary 495 ■ Questions 496 Chapter 15 Asymmetric Information 482 483 484 485 487 487 488 488 489 489 490 491 492 494 500 MANAGERIAL PROBLEM Limiting Managerial Incentives 15.1 Adverse Selection Adverse Selection in Insurance Markets Products of Unknown Quality Q&A 15.1 Q&A 15.2 MINI-CASE Reducing Consumers’ Information 15.2 Reducing Adverse Selection Restricting Opportunistic Behavior Equalizing Information MANAGERIAL IMPLICATION Using Brand Names and Warranties as Signals MINI-CASE Changing a Firm’s Name MINI-CASE Adverse Selection on eBay Motors 15.3 Moral Hazard Moral Hazard in Insurance Markets Moral Hazard in Principal-Agent Relationships MINI-CASE Selfless or Selfish Doctors? Q&A 15.3 15.4 Using Contracts to Reduce Moral Hazard Fixed-Fee Contracts Contingent Contracts MINI-CASE Contracts and Productivity in Agriculture Q&A 15.4 15.5 Using Monitoring to Reduce Moral Hazard Hostages MANAGERIAL IMPLICATION Efficiency Wages After-the-Fact Monitoring MINI-CASE Abusing Leased Cars MANAGERIAL SOLUTION Limiting Managerial Incentives Summary 528 ■ Questions 529 500 502 502 503 505 506 506 507 507 508 510 510 512 512 513 513 517 517 518 518 519 522 522 524 524 526 526 526 527 xii Contents Chapter 16 Government and Business 533 MANAGERIAL PROBLEM Licensing Inventions 16.1 Market Failure and Government Policy The Pareto Principle Cost-Benefit Analysis 16.2 Regulation of Imperfectly Competitive Markets Regulating to Correct a Market Failure Q&A 16.1 MINI-CASE Natural Gas Regulation Regulatory Capture Applying the Cost-Benefit Principle to Regulation 16.3 Antitrust Law and Competition Policy Mergers MINI-CASE Hospital Mergers: Market Power Versus Efficiency Predatory Actions Vertical Relationships MINI-CASE An Exclusive Contract for a Key Ingredient 16.4 Externalities MINI-CASE Negative Externalities from Spam The Inefficiency of Competition with Externalities Reducing Externalities MINI-CASE Pulp and Paper Mill Pollution and Regulation Q&A 16.2 MINI-CASE Why Tax Drivers The Coase Theorem MANAGERIAL IMPLICATION Buying a Town 16.5 Open-Access, Club, and Public Goods Open-Access Common Property MINI-CASE For Whom the Bridge Tolls Club Goods MINI-CASE Piracy Public Goods 16.6 Intellectual Property Patents Q&A 16.3 MANAGERIAL IMPLICATION Trade Secrets Copyright Protection MANAGERIAL PROBLEM Responding to Exchange Rates 17.1 Reasons for International Trade Comparative Advantage 536 537 539 540 542 Comparative Advantage Increasing Returns to Scale MINI-CASE Barbie Doll Varieties 17.2 Exchange Rates Determining the Exchange Rate Exchange Rates and the Pattern of Trade MANAGERIAL IMPLICATION Limiting Arbitrage and Gray Markets Managing Exchange Rate Risk 17.3 International Trade Policies Quotas and Tariffs in Competitive Markets 542 543 545 546 546 546 548 548 549 549 552 553 554 555 556 557 557 558 559 560 560 560 563 563 564 565 566 566 ■ Questions 569 573 533 534 535 536 MANAGERIAL SOLUTION Licensing Inventions Summary 568 Chapter 17 Global Business Q&A 17.1 MANAGERIAL IMPLICATION Paul Allen’s Q&A 17.2 MINI-CASE Managerial Responses to the Chicken Tax Trade War Rent Seeking Noncompetitive Reasons for Trade Policy MINI-CASE Dumping and Countervailing Duties for Solar Panels Trade Liberalization and the World Trading System Trade Liberalization Problems 17.4 Multinational Enterprises Becoming a Multinational MINI-CASE What’s an American Car? International Transfer Pricing Q&A 17.3 MINI-CASE Profit Repatriation 17.5 Outsourcing 573 575 575 577 578 578 579 580 580 581 582 582 583 583 588 589 589 590 592 593 594 595 596 596 597 598 600 601 MANAGERIAL SOLUTION Responding to Exchange Rates Summary 604 ■ Questions 603 605 Answers to Selected Questions Definitions References Sources for Managerial Problems, Mini-Cases, and Managerial Implications Index Credits E–1 E–13 E–18 E–24 E–32 E–51 Preface Successful managers make extensive use of economic tools when making important decisions. They use these tools to produce at minimum cost, to choose an output level to maximize profit, and for many other managerial decisions including: ◗ Whether to offer buy-one-get-one-free deals ◗ How much to advertise ◗ Whether to sell various goods as a bundle ◗ What strategies to use to compete with rival firms ◗ How to design compensation contracts to provide appropriate incentives for employees ◗ How to structure an international supply chain to take advantage of cross-country differences in production costs We illustrate how to apply economic theory using actual business examples and real data. Our experience teaching managerial economics at the Wharton School (University of Pennsylvania) and the Sauder School of Business (University of British Columbia) as well as teaching a wide variety of students at the Massachusetts Institute of Technology; Queen’s University; and the University of California, Berkeley, has convinced us that students prefer our emphasis on real-world issues and examples from actual markets. Main Innovations This book differs from other managerial economics texts in three main ways. ◗ It places greater emphasis than other texts on modern theories that are increasingly useful to managers in areas such as industrial organization, transaction cost theory, game theory, contract theory, and behavioral economics. ◗ It makes more extensive use of real-world business examples to illustrate how to use economic theory in making business decisions. ◗ It employs a problem-based approach to demonstrate how to apply economic theory to specific business decisions. Modern Theories for Business Decisions This book has all the standard economic theory, of course. However, what sets it apart is its emphasis on modern theories that are particularly useful for managers. Industrial Organization. How do managers differentiate their products to increase their profits? When do mergers pay off? When should a firm take (legal) xiii xiv Preface actions to prevent entry of rivals? What effects do government price regulations have on firms’ behavior? These and many other questions are addressed by industrial organization theories. Transaction Cost Theory. Why do some firms produce inputs while others buy them from a market? Why are some firms vertically integrated whiles others are not? We use transaction cost theory to address questions such as these, particularly in Chapter 7. Game Theory. Should the manager of a radio station schedule commercial breaks at the same time as rival firms? What strategy should a manager use when bidding in an auction for raw materials? The major issue facing many managers is deciding what strategies to use in competing with rivals. This book goes well beyond other managerial economics texts by making significant use of game theory in Chapters 12–14 to examine such topics as oligopoly quantity and price setting, entry and exit decisions, entry deterrence, and strategic trade policy. Game theory provides a way of thinking about strategies and it provides methods to choose strategies that maximize profits. Unlike most microeconomic and managerial economics books, our applications of game theory are devoted almost exclusively to actual business problems. Contract Theory. What kind of a contract should a manager offer a worker to induce the employee to work hard? How do managers avoid moral hazard problems so they aren’t taken advantage of by people who have superior information? We use modern contract theory to show how to write contracts to avoid or minimize such problems. Behavioral Economics. Should a manager allow workers to opt in or opt out of a retirement system? How can the manager of a motion picture firm take advantage of movie reviews? We address questions such as these using behavioral economics— one of the hottest new areas of economic theory—which uses psychological research and theory to explain why people deviate from rational behavior. These theories are particularly relevant for managers, but sadly they have been largely ignored by most economists until recently. Real-World Business Examples We demonstrate that economics is practical and useful to managers by examining real markets and actual business decisions. We do so in two ways. In our presentation of the basic theory, we use real-world data and examples. Second, we examine many real-world problems in our various application features. To illustrate important economic concepts, we use graphs and calculations based on actual markets and real data. Students learn the basic model of supply and demand using estimated supply and demand curves for avocados, and they practice estimating demand curves using real data such as from the Portland Fish Exchange. They study how imported oil limits pricing by U.S. oil producers using real estimated supply and demand curves, derive cost curves from Japanese beer manufacturers using actual estimated production functions, and analyze oligopoly strategies using estimated demand curves and cost and profit data from the real-world rivalries between United Airlines and American Airlines and between Coke and Pepsi. Preface xv Problem-Based Learning Managers have to solve business problems daily. We use a problem-solving approach to demonstrate how economic theory can help mangers make good decisions. In each chapter, we solve problems using a step-by-step approach to model good problem-solving techniques. At the end of the chapter, we have an extensive set of questions. Some of these require the student to solve problems similar to the solved problems in the chapter, while others ask the student to use the tools of the chapter to answer questions about applications within the chapter or new real-world problems. We also provide exercises asking students to use spreadsheets to apply the theory they have learned to real-world problems. Features This book has more features dedicated to showing students how to apply theory to real-world problems than do rival texts. Managerial Implications. Managerial Implications sections contain simple bottom-line statements of economic principles that managers can use to make key managerial decisions. For example, we describe how managers can assess whether they are maximizing profit by using data to estimate demand elasticities. We also show how they can structure discounts to maximize profits, promote customer loyalty, design auctions, prevent gray markets, and use important insights from game theory to improve managerial decisions. Mini-Cases. Over a hundred Mini-Cases apply economic theory to interesting and important managerial problems. For example, Mini-Cases demonstrate how price increases on iTunes affect music downloads (using actual data), how to estimate Blackberry’s production function using real-world data, why some top-end designers limit the number of designer bags customers can buy, how “poison pills” at Yahoo! affected shareholders, how Pfizer used limit pricing to slow entry of rivals, why advertisers pay so much for Superbowl commercials, and how managers of auto manufacturing firms react to tariffs and other regulations. Q&As. After the introductory chapter, each chapter provides three to five Q&As (Questions & Answers). Each Q&A poses a qualitative or quantitative problem and then uses a step-by-step approach to solve the problem. Most of the 55 Q&As focus on important managerial issues such as how a cost-minimizing firm would adjust to changing factor prices, how a manager prices bundles of goods to maximize profits, how to determine Intel’s and AMD’s profit-maximizing quantities and prices using their estimated demand curves and marginal costs, and how to allocate production across plants internationally. Managerial Problems and Managerial Solutions. After the introductory chapter, each chapter starts with a Managerial Problem that motivates the chapter by posing real-world managerial questions that can be answered using the economic principles and methods developed in the chapter. At the end of each chapter, we answer these questions in the Managerial Solution. Thus, each pair of these features combines the essence of a Mini-Case and a Q&A. xvi Preface End-of-Chapter Questions. Starting with Chapter 2, each chapter ends with an extensive set of questions, many of which are based on real-world problems. Each Q&A has at least one associated end-of-chapter question that references the Q&A and allows the student to answer a similar problem, and many of the questions are related to Mini-Cases that appear in the book. The answers to selected end-of-chapter problems appear at the end of the book, and all of the end-of-chapter questions are available in MyEconLab for self-assessment, homework, or testing. Spreadsheet Exercises. In addition to the verbal, graphical, and mathematical exercises, each chapter has two end-of-chapter spreadsheet exercises. These exercises demonstrate how managers can use a spreadsheet to apply the economic methods described in the chapter. They address important managerial issues such a choosing the profit-maximizing level of advertising or designing compensation contracts to effectively motivate employees. Students can complete the spreadsheet exercises in MyEconLab, which includes additional spreadsheet exercises. Using Calculus. Calculus presentations of the theory appear at the appropriate points in the text in a Using Calculus feature. In contrast, most other books relegate calculus to appendices, mix calculus in with other material where it cannot easily be skipped, or avoid calculus entirely. We have a few appendices, but most of our calculus material is in Using Calculus sections, which are clearly identified and structured as discrete treatments. Therefore this book may be conveniently used both by courses that use calculus and those that do not. Some end-of-chapter questions are designed to use calculus and are clearly indicated. Alternative Organizations Because instructors differ in the order in which they cover material and in the range of topics covered, this text has been designed for maximum flexibility. The most common approach to teaching managerial economics is to follow the sequence of the chapters in the order presented. However, many variations are possible. For example, some instructors choose to address empirical methods (Chapter 3) first. Some instructors skip consumer theory (Chapter 4), which they can safely do without causing problems in later chapters. Chapter 7, Firm Organization and Market Structure, provides an overview of the key issues that are discussed in later chapters, such as types of firms, profit maximization and its alternatives, conflicts between managers and owners (and other “agency” issues), and the structure of markets. We think that presenting this material early in the course is ideal, but all of this material except for the section on profit maximization can be covered later. Because our treatment of game theory is divided into two chapters (Chapters 12 and 13), instructors can conveniently choose how much game theory to present. Later chapters that reference game theory do so in such a way that the game theoretical material can be easily skipped. Although Chapter 11 on oligopoly and monopolistic competition precedes the game theory chapters, a course could cover the game theory chapters first (with only minor explanations by the instructor). And a common variant is to present Chapter 14 on uncertainty earlier in the course. The last chapter, Global Business (17), should be very valuable for instructors who take an international perspective. To promote this viewpoint, every chapter contains examples of dealing with firms based in a variety of countries in addition to the United States. Preface xvii MyEconLab MyEconLab’s powerful assessment and tutorial system works hand-in-hand with this book. Features for Students MyEconLab puts students in control of their learning through a collection of testing, practice, and study tools. Students can study on their own, or they can complete assignments created by their instructor. In MyEconLab’s structured environment, students practice what they learn, test their understanding, and pursue a personalized study plan generated from their performance on sample tests and quizzes. In Homework or Study Plan mode, students have access to a wealth of tutorial features, including the following: ◗ Instant feedback on exercises taken directly from the text helps students understand and apply the concepts. ◗ Links to the eText version of this textbook allow the student to quickly revisit a concept or an explanation. ◗ Enhanced Pearson eText, available within the online course materials and offline via an iPad/Android app, allows instructors and students to highlight, bookmark, and take notes. ◗ Learning aids help students analyze a problem in small steps, much the same way an instructor would do during office hours. ◗ Temporary Access for students who are awaiting financial aid provides a 14-day grace period of temporary access. Experiments in MyEconLab Experiments are a fun and engaging way to promote active learning and mastery of important economic concepts. Pearson’s Experiment program is flexible and easy for instructors and students to use. ◗ Single-player experiments allow students to play against virtual players from anywhere at any time they have an Internet connection. ◗ Multiplayer experiments allow instructors to assign and manage a real-time experiment with their classes. ◗ Pre- and post-questions for each experiment are available for assignment in MyEconLab. For a complete list of available experiments, visit www.myeconlab.com. Features for Instructors MyEconLab includes comprehensive homework, quiz, text, and tutorial options, where instructors can manage all assessment needs in one program. ◗ All of the end-of-chapter questions are available for assignment and auto-grading. ◗ Test Item File questions are available for assignment or testing. ◗ The Custom Exercise Builder allows instructors the flexibility of creating their own problems for assignments. xviii Preface ◗ The powerful Gradebook records each student’s performance and time spent on the tests, study plan, and homework and can generate reports by student or by chapter. ◗ Advanced Communication Tools enable students and instructors to communicate through email, discussion board, chat, and ClassLive. ◗ Customization options provide new and enhanced ways to share documents, add content, and rename menu items. ◗ A prebuilt course option provides a turn-key method for instructors to create a MyEconLab course that includes assignments by chapter. Supplements A full range of supplementary materials to support teaching and learning accompanies this book. ◗ The Online Instructor’s Manual by Souren Soumbatiants of Franklin University has many useful and creative teaching ideas. It also offers additional discussion questions, and provides solutions for all the end-of-chapter questions in the text. ◗ The Online Test Bank by Todd Fitch of the University of California, Berkeley, features problems of varying levels of complexity, suitable for homework assignments and exams. Many of these multiple-choice questions draw on current events. ◗ The Computerized Test Bank reproduces the Test Bank material in the TestGen software, which is available for Windows and Macintosh. With TestGen, instructors can easily edit existing questions, add questions, generate tests, and print the tests in a variety of formats. ◗ The Online PowerPoint Presentation by Nelson Altamirano of National University contains text figures and tables, as well as lecture notes. These slides allow instructors to walk through examples from the text during in-class presentations. These teaching resources are available online for download at the Instructor Resource Center, www.pearsonhighered.com/perloff, and on the catalog page for Managerial Economics and Strategy. Acknowledgments Our greatest debt is to our very patient students at MIT; the University of British Columbia; the University of California, Berkeley; and the University of Pennsylvania for tolerantly dealing with our various approaches to teaching them economics. We appreciate their many helpful (and usually polite) suggestions. We also owe a great debt to our editors, Adrienne D’Ambrosio and Jane Tufts. Adrienne D’Ambrosio, Executive Acquisitions Editor, was involved in every stage in designing the book, writing the book, testing it, and developing supplemental materials. Jane Tufts, our developmental editor, reviewed each chapter of this book for content, pedagogy, and presentation. By showing us how to present the material as clearly and thoroughly as possible, she greatly strengthened this text. Preface xix Our other major debt is to Satyajit Ghosh, University of Scranton, for doing most of the work on the spreadsheet exercises in the chapters and in MyEconLab. We benefitted greatly from his creative ideas about using spreadsheets to teach managerial economics. We thank our teaching colleagues who provided many helpful comments and from whom we have shamelessly borrowed ideas. We particularly thank Tom Davidoff, Stephen Meyer, Nate Schiff, Ratna Shrestha, Mariano Tappata, and James Vercammen for using early versions of the textbook and for making a wide range of helpful contributions. We are also grateful to our colleagues Jen Baggs, Dennis Carlton, Jean-Etienne de Bettignes, Keith Head, Larry Karp, John Ries, Tom Ross, Leo Simon, Chloe Tergiman, and Ralph Winter for many helpful comments. We thank Evan Flater, Kai Rong Gan, Guojun He, Joyce Lam, WeiYi Shen, and Louisa Yeung for their valuable work as research assistants on the book. We are very grateful to the many reviewers who spent untold hours reading and commenting on our original proposal and several versions of each chapter. Many of the best ideas in this book are due to them. We’d especially like to thank Kristen Collett-Schmitt, Matthew Roelofs, and Adam Slawski for carefully reviewing the accuracy of the entire manuscript multiple times and for providing very helpful comments. We thank all the following reviewers, all of whom provided valuable comments at various stages: Laurel Adams, Northern Illinois University Jack Hou, California State University, Long Beach James C. W. Ahiakpor, California State University, East Bay Timothy James, Arizona State University Nelson Altamirano, National University Peter Daniel Jubinski, St. Joseph’s University Ariel Belasen, Southern Illinois University, Edwardsville Chulho Jung, Ohio University Bruce C. Brown, California State Polytechnic University, Pomona Barry Keating, University of Notre Dame Donald Bumpass, Sam Houston State University Dale Lehman, Alaska Pacific University Tom K. Lee, California State University, Northridge James H. Cardon, Brigham Young University Vincent J. Marra Jr., University of Delaware Jihui Chen, Illinois State University Sheila J. Moore, California Lutheran University Ron Cheung, Oberlin College Thomas Patrick, The College of New Jersey Abdur Chowdhury, Marquette University Anita Alves Pena, Colorado State University George Clarke, Texas A&M International University Troy Quast, Sam Houston State University Kristen Collett-Schmitt, University of Notre Dame Barry Ritchey, Anderson University Douglas Davis, Virginia Commonwealth University Matthew R. Roelofs, Western Washington University Christopher S. Decker, University of Nebraska, Omaha Amit Sen, Xavier University Craig A. Depken, II, University of North Carolina, Charlotte Stephanie Shayne, Husson University Jed DeVaro, California State University, East Bay Adam Slawski, Pennsylvania State University David Ely, San Diego State University Caroline Swartz, University of North Carolina, Charlotte Asim Erdilek, Case Western Reserve University Scott Templeton, Clemson University Satyajit Ghosh, University of Scranton Keith Willett, Oklahoma State University Rajeev Goel, Illinois State University Douglas Wills, University of Washington, Tacoma Abbas P. Grammy, California State University, Bakersfield Mark L. Wilson, Troy University Clifford Hawley, West Virginia University David Wong, California State University, Fullerton Matthew John Higgins, Georgia Institute of Technology xx Preface It was a pleasure to work with the excellent staff at Pearson, who were incredibly helpful in producing this book. Meredith Gertz did a wonderful job of supervising the production process, assembling the extended publishing team, and managing the design of the handsome interior. Gillian Hall and the rest of the team at The Aardvark Group Publishing Services, including our copyeditor, Rebecca Greenberg, have our sincere gratitude for designing the book and keeping the project on track and on schedule. Ted Smykal did a wonderful job drawing most of the cartoons. Sarah Dumouchelle helped edit, arranged for the supplements, and was helpful in many other ways. We also want to acknowledge, with appreciation, the efforts of Melissa Honig, Courtney Kamauf, and Noel Lotz in developing MyEconLab, the online assessment and tutorial system for the book. Finally, we thank our wives, Jackie Persons and Barbara Spencer, for their great patience and support during the nearly endless writing process. We apologize for misusing their names—and those of our other relatives and friends—in the book! J. M. P. J. A. B. Introduction 1 An Economist’s Theory of Reincarnation: If you’re good, you come back on a higher level. Cats come back as dogs, dogs come back as horses, and people—if they’ve been very good like George Washington—come back as money. I f all the food, clothing, entertainment, and other goods and services we wanted were freely available, no one would study economics, and we would not need managers. However, most of the good things in life are scarce. We cannot have everything we want. Consumers cannot consume everything but must make choices about what to purchase. Similarly, managers of firms cannot produce everything and must make careful choices about what to produce, how much to produce, and how to produce it. Studying such choices is the main subject matter of economics. Economics is the study of decision making in the presence of scarcity.1 Managerial economics is the application of economic analysis to managerial decision making. Managerial economics concentrates on how managers make economic decisions by allocating the scarce resources at their disposal. To make good decisions, a manager must understand the behavior of other decision makers, such as consumers, workers, other managers, and governments. In this book, we examine decision making by such participants in the economy, and we show how managers can use this understanding to be successful. Ma in Topics In this chapter, we examine two main topics: 1.1 1. Managerial Decision Making: Economic analysis helps managers develop strategies to achieve a firm’s objective—such as maximizing profit—in the presence of scarcity. 2. Economic Models: Managers use models based on economic theories to help make predictions about consumer and firm behavior, and as an aid to managerial decision making. Managerial Decision Making A firm’s managers allocate the limited resources available to them to achieve the firm’s objectives. The objectives vary for different managers within a firm. A production manager’s objective is normally to achieve a production target at the lowest possible cost. A marketing manager must allocate an advertising budget to promote the product most effectively. Human resource managers design compensation systems 1Many dictionaries define economics as the study of the production, distribution, and consumption of goods and services. However, professional economists think of economics as applying more broadly, including any decisions made subject to scarcity. 1 2 CHAPTER 1 Introduction to encourage employees to work hard. The firm’s top manager must coordinate and direct all these activities. Each of these tasks is constrained by resource scarcity. At any moment in time, a production manager has to use the existing factory and a marketing manager has a limited marketing budget. Such resource limitations can change over time but managers always face constraints. Profit Most private sector firms want to maximize profit, which is the difference between revenue and cost. The job of the senior manager in a firm, usually called the chief executive officer (CEO), is to focus on the bottom line: maximizing profit. The CEO orders the production manager to minimize the cost of producing the particular good or service, asks the market research manager to determine how many units can be sold at any given price, and so forth. Minimizing cost helps the firm to maximize profit, but the CEO must also decide how much output to produce and what price to charge. It is the job of the CEO (and other senior executives) to ensure that all managerial functions are coordinated so that the firm makes as much profit as possible. It would be a major coordination failure if the marketing department set up a system of pricing and advertising based on selling 8,000 units a year, while the production department managed to produce only 2,000 units. The CEO is also often concerned with how a firm is positioned in a market relative to its rivals. Senior executives at Coca-Cola and Pepsi spend a lot of time worrying about each other’s actions. Managers in such situations have a natural tendency to view business rivalries like sporting events, with a winner and a loser. However, it is critical to the success of any firm that the CEO focus on maximizing the firm’s profit rather than beating a rival. Trade-Offs People and firms face trade-offs because they can’t have everything. Managers must focus on the trade-offs that directly or indirectly affect profits. Evaluating tradeoffs often involves marginal reasoning: considering the effect of a small change. Key trade-offs include: ◗ How to produce: To produce a given level of output, a firm must use more of one input if it uses less of another input. Car manufacturers choose between metal and plastic for many parts, which affects the car’s weight, cost, and safety. ◗ What prices to charge: Some firms, such as farms, have little or no control over the prices at which their goods are sold and must sell at the price determined in the market. However, many other firms set their prices. When a manager of such a firm sets the price of a product, the manager must consider whether raising the price by a dollar increases the profit margin on each unit sold by enough to offset the loss from selling fewer units. Consumers, given their limited budgets, buy fewer units of a product when its price rises. Thus, ultimately, the manager’s pricing decision is constrained by the scarcity under which consumers make decisions. 1.2 Economic Models 3 Other Decision Makers It is important for managers of a firm to understand how decisions made by consumers, workers, managers of other firms, and governments constrain their firm. Consumers purchase products subject to their limited budgets. Workers decide on which jobs to take and how much to work given their scarce time and limits on their abilities. Rivals may introduce new, superior products or cut the prices of existing products. Governments around the world may tax, subsidize, or regulate products. Thus, managers must understand how others make decisions. Most economic analysis is based on the assumption that decision makers are maximizers: they do the best they can with their limited resources. However, economists also consider some contexts in which economic decision makers do not successfully maximize for a variety of psychological reasons—a topic referred to as behavioral economics. Interactions between economic decision makers take place primarily in markets. A market is an exchange mechanism that allows buyers to trade with sellers. A market may be a town square where people go to trade food and clothing, or it may be an international telecommunications network over which people buy and sell financial securities. When we talk about a single market, we refer to trade in a single good or group of goods that are closely related, such as soft drinks, movies, novels, or automobiles. The primary participants in a market are firms that supply the product and consumers who buy it, but government policies such as taxes also play an important role in the operation of markets. Strategy When interacting with a small number of rival firms, a manager uses a strategy—a battle plan that specifies the actions or moves that the manager will make to maximize the firm’s profit. A CEO’s strategy might involve choosing the level of output, the price, or advertising now and possibly in the future. In setting its production levels and price, Pepsi’s managers must consider what choices Coca-Cola’s managers will make. One tool that is helpful in understanding and developing such strategies is game theory, which we use in several chapters. 1.2 Economic Models Economists use economic models to explain how managers and other decision makers make decisions and to explain the resulting market outcomes. A model is a description of the relationship between two or more variables. Models are used in many fields. For example, astronomers use models to describe and predict the movement of comets and meteors, medical researchers use models to describe and predict the effect of medications on diseases, and meteorologists use models to predict weather. Business economists construct models dealing with economic variables and use such models to describe and predict how a change in one variable will affect another. Such models are useful to managers in predicting the effects of their decisions and in understanding the decisions of others. Models allow managers to consider hypothetical situations—to use a what-if analysis—such as “What would happen if we raised our prices by 10%?” or “Would profit rise if we phased out one of our product lines?” Models help managers predict answers to what-if questions and to use those answers to make good decisions. CHAPTER 1 4 Mini-Case Using an Income Threshold Model in China Introduction According to an income threshold model, no one who has an income level below a particular threshold buys a particular consumer durable, such as a refrigerator or car. The theory also holds that almost everyone whose income is above that threshold buys the product. If this theory is correct, we predict that, as most people's incomes rise above the threshold in emergent economies, consumer durable purchases will increase from near zero to large numbers virtually overnight. This prediction is consistent with evidence from Malaysia, where the income threshold for buying a car is about $4,000. In China, incomes have risen rapidly and now exceed the threshold levels for many types of durable goods. As a result, many experts correctly predicted that the greatest consumer durable goods sales boom in history would take place there. Anticipating this boom, many companies have greatly increased their investments in durable goods manufacturing plants in China. Annual foreign direct investments have gone from $916 million a year in 1983 to $116 billion in 2011. In expectation of this growth potential, even traditional political opponents of the People's Republic—Taiwan, South Korea, and Russia—are investing in China. One of the most desirable durable goods is a car. Li Rifu, a 46-year-old Chinese farmer and watch repairman, thought that buying a car would improve the odds that his 22- and 24-year-old sons would find girlfriends, marry, and produce grandchildren. Soon after Mr. Li purchased his Geely King Kong for the equivalent of $9,000, both sons met girlfriends, and his older son got married. Four-fifths of all new cars sold in China are bought by first-time customers. An influx of first-time buyers was responsible for China's ninefold increase in car sales from 2000 to 2009. By 2010, China became the second largest producer of automobiles in the world, trailing only Germany. In addition, foreign automobile companies built Chinese plants. For example, Ford invested $600 million in its Chongqing factory in 2012.2 Simplifying Assumptions Everything should be made as simple as possible, but not simpler. —Albert Einstein A model is a simplification of reality. The objective in building a model is to include the essential issues, while leaving aside the many complications that might distract us or disguise those essential elements. For example, the income threshold model focuses on only the relationship between income and purchases of durable goods. Prices, multiple car purchases by a single consumer, and other factors that might affect durable goods purchases are left out of the model. Despite these simplifications, the model—if correct—gives managers a good general idea of how the automobile market is likely to evolve in countries such as China. We have described the income threshold model in words, but we could have presented it using graphs or mathematics. Representing economic models using mathematical formulas in spreadsheets has become very important in managerial decision making. Regardless of how the model is described, an economic model is a simplification of reality that contains only its most important features. Without simplifications, it is difficult to make predictions because the real world is too complex to analyze fully. 2The sources for Mini-Cases are available at the back of the book. 1.2 Economic Models 5 Economists make many assumptions to simplify their models. When using the income threshold model to explain car purchasing behavior in China, we assume that factors other than income, such as the color of cars, do not have an important effect on the decision to buy cars. Therefore, we ignore the color of cars that are sold in China in describing the relationship between income and the number of cars consumers want. If this assumption is correct, by ignoring color, we make our analysis of the auto market simpler without losing important details. If we’re wrong and these ignored issues are important, our predictions may be inaccurate. Part of the skill in using economic models lies in selecting a model that is appropriate for the task at hand. Testing Theories Blore’s Razor: When given a choice between two theories, take the one that is funnier. Economic theory refers to the development and use of a model to test hypotheses, which are proposed explanations for some phenomenon. A useful theory or hypothesis is one that leads to clear, testable predictions. A theory that says “If the price of a product rises, the quantity demanded of that product falls” provides a clear prediction. A theory that says “Human behavior depends on tastes, and tastes change randomly at random intervals” is not very useful because it does not lead to testable predictions and provides little explanation of the choices people make. Economists test theories by checking whether the theory’s predictions are correct. If a prediction does not come true, they might reject the theory—or at least reduce their confidence in the theory. Economists use a model until it is refuted by evidence or until a better model is developed for a particular use. A good model makes sharp, clear predictions that are consistent with reality. Some very simple models make sharp or precise predictions that are incorrect. Some more realistic and therefore more complex models make ambiguous predictions, allowing for any possible outcome, so they are untestable. Neither incorrect models nor untestable models are helpful. The skill in model building lies in developing a model that is simple enough to make clear predictions but is realistic enough to be accurate. Any model is only an approximation of reality. A good model is one that is a close enough approximation to be useful. Although economists agree on the methods they use to develop and apply testable models, they often disagree on the specific content of those models. One model might present a logically consistent argument that prices will go up next quarter. Another, using a different but equally logical theory, may contend that prices will fall next quarter. If the economists are reasonable, they will agree that pure logic alone cannot resolve their dispute. Indeed, they will agree that they’ll have to use empirical evidence—facts about the real world—to find out which prediction is correct. One goal of this book is to teach managers how to think like economists so that they can build, apply, and test economic models to deal with important managerial problems. Positive and Normative Statements Economic analysis sometimes leads to predictions that seem undesirable or cynical. For instance, an economist doing market research for a producer of soft drinks might predict that “if we double the amount of sugar in this soft drink we will significantly increase sales to children.” An economist making such a statement is not seeking to undermine the health of children by inducing them to consume excessive amounts of sugar. The economist is only making a scientific prediction about the relationship between cause and effect: more sugar in soft drinks is appealing to children. 6 CHAPTER 1 Introduction Such a scientific prediction is known as a positive statement: a testable hypothesis about matters of fact such as cause-and-effect relationships. Positive does not mean that we are certain about the truth of our statement; it indicates only that we can test the truth of the statement. An economist may test the hypothesis that the quantity of soft drinks demanded decreases as the price increases. Some may conclude from that study that “The government should tax soft drinks so that people will not consume so much sugar.” Such a statement is a value judgment. It may be based on the view that people should be protected from their own unwise choices, so the government should intervene. This judgment is not a scientific prediction. It is a normative statement: a belief about whether something is good or bad. A normative statement cannot be tested because a value judgment cannot be refuted by evidence. A normative statement concerns what somebody believes should happen; a positive statement concerns what is or what will happen. Normative statements are sometimes called prescriptive statements because they prescribe a course of action, while positive statements are sometimes called descriptive statements because they describe reality. Although a normative conclusion can be drawn without first conducting a positive analysis, a policy debate will be better informed if a positive analysis is conducted first.3 Good economists and managers emphasize positive analysis. This emphasis has implications for what we study and even for our use of language. For example, many economists stress that they study people’s wants rather than their needs. Although people need certain minimum levels of food, shelter, and clothing to survive, most people in developed economies have enough money to buy goods well in excess of the minimum levels necessary to maintain life. Consequently, in wealthy countries, calling something a “need” is often a value judgment. You almost certainly have been told by some elder that “you need a college education.” That person was probably making a value judgment—“you should go to college”—rather than a scientific prediction that you will suffer terrible economic deprivation if you do not go to college. We can’t test such value judgments, but we can test a (positive) hypothesis such as “Graduating from college or university increases lifetime income.” S U MMARY 1. Managerial Decision Making. Economic analy- 2. Economic Models. Managers use models based sis helps managers develop strategies to pursue their objectives effectively in the presence of scarcity. Various managers within a firm face different objectives and different constraints, but the overriding objective in most private-sector firms is to maximize profits. Making decisions subject to constraints implies making trade-offs. To make good managerial decisions, managers must understand how consumers, workers, other managers, and governments will act. Economic theories normally (but not always) assume that all decision makers attempt to maximize their well-being given the constraints they face. on economic theories to help make predictions and decisions, which they use to run their firms. A good model is simple to use and makes clear, testable predictions that are supported by evidence. Economists use models to construct positive hypotheses such as causal statements linking changes in one variable, such as income, to its effects, such as purchases of automobiles. These positive propositions can be tested. In contrast, normative statements, which are value judgments, cannot be tested. 3Some argue that, as (social) scientists, we economists should present only positive analyses. Others argue that we shouldn't give up our right to make value judgments just like the next person (who happens to be biased, prejudiced, and pigheaded, unlike us). Supply and Demand 2 Talk is cheap because supply exceeds demand. M a nagerial P roblem Carbon Taxes Burning fossil fuels such as gasoline, coal, and heating oil releases gases containing carbon into the atmosphere.1 These “greenhouse” gases are widely believed to contribute to global warming. To reduce this problem and raise tax revenues, many environmentalists and political leaders have proposed levying a carbon tax on the carbon content in fossil fuels.2 When governments impose carbon taxes on gasoline, managers of firms that sell gasoline need to think about how much of the tax they have to absorb and how much they can pass through to firms and consumers who buy gasoline. Similarly, managers of firms that purchase gasoline must consider how any pass-through charges will affect their costs of shipping, air travel, heating, and production. This pass-through analysis is critical in making short-run managerial decisions concerning how much to produce, whether to operate or shut down, and how to set prices and make long-run decisions such as whether to undertake capital investments. The first broad-based carbon taxes on fuels containing carbon (such as gasoline) were implemented in Finland and Sweden at the beginning of the 1990s. Various other European countries soon followed suit. However, strong opposition to carbon taxes has limited adoption in the United States and Canada. The first North American carbon tax was not introduced until 2006 in Boulder, Colorado, where it was applied to only electricity generation. In 2007 and 2008, the Canadian provinces of Quebec and British Columbia became the first provinces or states in North America to impose a broad-based carbon tax. Australia adopted a carbon tax in 2012. During the 2012–2013 U.S. federal government budget negotiations, several Congressional leaders called for carbon taxes to help balance the budget. Such carbon taxes harm some industries and help others. The tax hurts owners and managers of gasoline retailing firms, who need to consider whether they can stay in business in the face of a significant carbon tax. Shippers and 1Each chapter from Chapter 2 on begins with a Managerial Problem that contains a specific question, which is answered at the end of the chapter using the theories presented in the chapter. Sources for the Managerial Problems, Mini-Cases, and Managerial Implications appear at the back of the book. 2Their political opponents object, claiming that fears about global warming are exaggerated and warning of large price increases from such taxes. 7 8 CHAPTER 2 Supply and Demand manufacturers that use substantial amounts of fuel in production, as well as other firms, would also see their costs of operating rise. Although a carbon tax harms some firms and industries, it creates opportunities for others. For example, wind power, which is an alternative to fossil fuels in generating electricity, would become much more attractive. Anticipating greater opportunities in this market in the future, Google invested nearly $1 billion in wind and other renewable energy as of 2012. In 2013, Warren Buffett acquired two utility-scale solar plants in Southern California for between $2 and $2.5 billion. DONG Energy A/S and Iberdrola (IBE) SA’s Scottish Power unit announced that they would invest £1.6 billion ($2.6 billion) to build a large wind farm off northwest England by 2014. Motor vehicle sector managers would need to consider whether to change their product mix in response to a carbon tax, perhaps focusing more on fuel-efficient vehicles. Even without a carbon tax, recent increases in gasoline prices have induced consumers to switch from sport utility vehicles (SUVs) to smaller cars. A carbon tax would favor fuel-efficient vehicles even more. At the end of this chapter, we will return to this topic and answer a question of critical importance to managers in the motor vehicle industry and in other industries affected by gasoline prices: What will be the effect of imposing a carbon tax on the price of gasoline? T o analyze the price and other effects of carbon taxes, managers use an economic tool called the supply-and-demand model. Managers who are able to anticipate and act on the implications of the supply-and-demand model by responding quickly to changes in economic conditions, such as tax changes, make more profitable decisions. The supply-and-demand model provides a good description of many markets and applies particularly well to markets in which there are many buyers and many sellers, as in most agricultural markets, much of the construction industry, many retail markets (such as gasoline retailing), and several other major sectors of the economy. In markets where this model is applicable, it allows us to make clear, testable predictions about the effects of new taxes or other shocks on prices and other market outcomes. M ain Topics In this chapter, we examine six main topics 1. Demand: The quantity of a good or service that consumers demand depends on price and other factors such as consumer incomes and the prices of related goods. 2. Supply: The quantity of a good or service that firms supply depends on price and other factors such as the cost of inputs and the level of technological sophistication used in production. 3. Market Equilibrium: The interaction between consumers’ demand and producers’ supply determines the market price and quantity of a good or service that is bought and sold. 4. Shocks to the Equilibrium: Changes in a factor that affect demand (such as consumer income) or supply (such as the price of inputs) alter the market price and quantity sold of a good or service. 5. Effects of Government Interventions: Government policy may also affect the equilibrium by shifting the demand curve or the supply curve, restricting price or quantity, or using taxes to create a gap between the price consumers pay and the price firms receive. 6. When to Use the Supply-and-Demand Model: The supply-and-demand model applies very well to highly competitive markets, which are typically markets with many buyers and sellers. 2.1 Demand 2.1 9 Demand Consumers decide whether to buy a particular good or service and, if so, how much to buy based on its price and on other factors, including their incomes, the prices of other goods, their tastes, and the information they have about the product. Government regulations and other policies also affect buying decisions. Before concentrating on the role of price in determining quantity demanded, let’s look briefly at some other factors. Income plays a major role in determining what and how much to purchase. People who suddenly inherit great wealth might be more likely to purchase expensive Rolex watches or other luxury items and would probably be less likely to buy inexpensive Timex watches and various items targeted toward lower-income consumers. More broadly, when a consumer’s income rises, that consumer will often buy more of many goods. The price of a related good might also affect consumers’ buying decisions. Related goods can be either substitutes or complements. A substitute good is a good that might be used or consumed instead of the good in question. Before deciding to go to a movie, a consumer might consider the prices of potential substitutes such as streaming a movie purchased online or going to a sporting event or a concert. Streaming movies, sporting events, and concerts compete with movie theaters for the consumer’s entertainment dollar. If sporting events are too expensive, many consumers might choose to see movies instead. Different brands of essentially the same good are often very close substitutes. Before buying a pair of Levi’s jeans, a customer might check the prices of other brands and substitute one of those brands for Levi’s if its price is sufficiently attractive. A complement is a good that is used with the good under consideration. Digital audio players such as the iPod application (app) for the iPhone and online audio recordings are complements because consumers obtain recordings online and then download them to audio players to listen to them. A decline in the price of digital audio players would affect the demand for online music. As consumers respond to the decline in the price of audio players by purchasing more such devices, they would also be more inclined to purchase and download online music. Thus, sellers of online music would experience an increase in demand for their product arising from the price decline of a complementary good (audio players). Consumers’ tastes are important in determining their demand for a good or service. Consumers do not purchase foods they dislike or clothes they view as unfashionable or uncomfortable. The importance of fashion illustrates how changing tastes affect consumer demand. Clothing items that have gone out of fashion can often be found languishing in discount sections of clothing stores even though they might have been readily purchased at high prices a couple of years (or even a few weeks) earlier when they were in fashion. Firms devote significant resources to trying to change consumer tastes through advertising. Similarly, information about the effects of a good has an impact on consumer decisions. In recent years, as positive health outcomes have been linked to various food items, demand for these healthy foods (such as soy products and high-fiber breads) has typically risen when the information became well known. Government rules and regulations affect demand. If a city government bans the use of skateboards on its streets, demand for skateboards in that city falls. Governments might also restrict sales to particular groups of consumers. For example, many political jurisdictions do not allow children to buy tobacco products, which reduces the quantity of cigarettes consumed. 10 CHAPTER 2 Supply and Demand Other factors might also affect the demand for specific goods. For example, consumers are more likely to use Facebook if most of their friends use Facebook. This network effect arises from the benefits of being part of a network and from the potential costs of being outside the network. Although many factors influence demand, economists focus most on how a good’s own price affects the quantity demanded. The relationship between price and quantity demanded plays a critical role in determining the market price and quantity in supply-and-demand analysis. To determine how a change in price affects the quantity demanded, economists ask what happens to quantity when price changes and other factors affecting demand such as income and tastes are held constant. The Demand Curve The amount of a good that consumers are willing to buy at a given price, holding constant the other factors that influence purchases, is the quantity demanded. The quantity demanded of a good or service can exceed the quantity actually sold. For example, as a promotion, a local store might sell DVDs for $2 each today only. At that low price, you might want to buy 25 DVDs, but the store might run out of stock before you can select the DVDs you want. Or the store might limit each consumer to a maximum of, for example, 10 DVDs. The quantity you demand is 25; it is the amount you want, even though the amount you actually buy might be only 10. Using a diagram, we can show the relationship between price and the quantity demanded. A demand curve shows the quantity demanded at each possible price, holding constant the other factors that influence purchases. Figure 2.1 shows the estimated monthly demand curve, D1, for avocados in the United States.3 Although this demand curve is a straight line, demand curves may also be smooth curves or wavy lines. By convention, the vertical axis of the graph measures the price, p, per unit of the good. Here the price of avocados is measured in dollars per pound (abbreviated “lb”). The horizontal axis measures the quantity, Q, of the good, which is usually expressed in some physical measure per time period. Here, the quantity of avocados is measured in millions of pounds (lbs) per month. The demand curve hits the vertical axis at $4, indicating that no quantity is demanded when the price is $4 per lb or higher. The demand curve hits the horizontal quantity axis at 160 million lbs, the quantity of avocados that consumers would want if the price were zero. To find out what quantity is demanded at a price between zero and $4, we pick that price—say, $2—on the vertical axis, draw a horizontal line across until we hit the demand curve, and then draw a vertical line down to the horizontal quantity axis. As the figure shows, the quantity demanded at a price of $2 per lb is 80 million lbs per month. One of the most important things to know about the graph of a demand curve is what is not shown. All relevant economic variables that are not explicitly 3To obtain our estimated supply and demand curves, we used estimates from Carman (2007), which we updated with more recent (2012) data from the California Avocado Commission and supplemented with information from other sources. The numbers have been rounded so that the figures use whole numbers. 2.1 Demand 11 The estimated demand curve, D1, for avocados shows the relationship between the quantity demanded per month and the price per lb. The downward slope of this demand curve shows that, holding other factors that influence demand constant, consumers demand fewer avocados when the price is high and more when the price is low. That is, a change in price causes a movement along the demand curve. p, $ per lb F IG U RE 2. 1 A Demand Curve 4.00 3.00 2.00 1.50 Avocado demand curve, D1 0 40 80 100 160 Q, Million lbs of avocados per month shown on the demand curve graph—income, prices of other goods (such as other fruits or vegetables), tastes, information, and so on—are held constant. Thus, the demand curve shows how quantity varies with price but not how quantity varies with income, the price of substitute goods, tastes, information, or other variables. Effects of a Price Change on the Quantity Demanded. One of the most important results in economics is the Law of Demand: consumers demand more of a good if its price is lower, holding constant income, the prices of other goods, tastes, and other factors that influence the amount they want to consume. According to the Law of Demand, demand curves slope downward, as in Figure 2.1. A downward-sloping demand curve illustrates that consumers demand a larger quantity of this good when its price is lowered and a smaller quantity when its price is raised. What happens to the quantity of avocados demanded if the price of avocados drops and all other variables remain constant? If the price of avocados falls from $2.00 per lb to $1.50 per lb in Figure 2.1, the quantity consumers want to buy increases from 80 million lbs to 100 million lbs.4 Similarly, if the price increases from $2 to $3, the quantity consumers demand decreases from 80 to 40. These changes in the quantity demanded in response to changes in price are movements along the demand curve. Thus, the demand curve is a concise summary of the answer to the question “What happens to the quantity demanded as the price changes, when all other factors are held constant?” Although we generally expect demand curves to slope down as does the one for avocados, a vertical or horizontal demand curve is possible. We can think of horizontal and vertical demand curves as being extreme cases of downward-sloping demand. The Law of Demand rules out demand curves that have an upward slope. The Law of Demand is an empirical claim—a claim about what actually happens. It is not a claim about general theoretical principles. It is theoretically possible that 4From now on, we will not state the relevant physical and time period measures unless they are particularly relevant. We refer to quantity rather than specific units per time period such as “million lbs per month” and price rather than “dollars per lb.” Thus, we say that the price is $2 (with the “per lb” understood) and the quantity as 80 (with the “millions of lbs per month” understood). 12 CHAPTER 2 Supply and Demand a demand curve could slope upward. However, the available empirical evidence strongly supports the Law of Demand. Effects of Other Factors on Demand. A demand curve shows the effects of price changes when all other factors that affect demand are held constant. But we are often interested in how other factors affect demand. For example, we might be interested in the effect of changes in income on the amount demanded. How would we illustrate the effect of income changes on demand? One approach is to draw the demand curve in a three-dimensional diagram with the price of avocados on one axis, income on a second axis, and the quantity of avocados on the third axis. But just thinking about drawing such a diagram is hard enough, and actually drawing it without sophisticated graphing software is impossible for many of us. Economists use a simpler approach to show the effect of factors other than a good’s own price on demand. A change in any relevant factor other than the price of the good causes a shift of the demand curve rather than a movement along the demand curve. These shifts can be readily illustrated in suitable diagrams. The price of substitute goods affects the quantity of avocados demanded. Many consumers view tomatoes as a substitute for avocados. If the price of tomatoes rises, consumers are more inclined to use more avocados instead, and the demand for avocados rises. The original, estimated avocado demand curve in Figure 2.1 is based on an average price of tomatoes of $0.80 per lb. Figure 2.2 shows how the avocado demand curve shifts outward or to the right from the original demand curve D1 to a new demand curve D2 if the price of tomatoes increases by 55¢ to $1.35 per lb. On the new demand curve, D2, more avocados are demanded at any given price than on D1 because tomatoes, a substitute good, have become more expensive. At a price of $2 per lb, the quantity of avocados demanded goes from 80 million lbs on D 1, before the increase in the price of tomatoes, to 91 million lbs on D2, after the increase. Similarly, consumers tend to buy more avocados as their incomes rise. Thus, if income rises, the demand curve for avocados shifts to the right, indicating that consumers demand more avocados at any given price. The demand curve for avocados shifts to the right from D1 to D2 as the price of tomatoes, a substitute, increases by 55¢ per lb. As a result of the increase in the price of tomatoes, more avocados are demanded at any given price. p, $ per lb F IG U RE 2. 2 A Shift of the Demand Curve D1, tomatoes 80¢ per lb D 2, tomatoes $1.35 per lb Effect of a 55¢ increase in the price of tomatoes 2.00 0 80 91 Q, Million lbs of avocados per month 2.1 Demand 13 In addition, changes in other factors that affect demand, such as information, can shift a demand curve. Reinstein and Snyder (2005) found that movie reviews affect the demand for some types of movies. Holding price constant, they determined that if a film received two-thumbs-up reviews on the then extremely popular Siskel and Ebert movie-review television program the opening weekend demand curve shifted to the right by 25% for a drama, but the demand curve did not significantly shift for an action film or a comedy. To properly analyze the effects of a change in some variable on the quantity demanded, we must distinguish between a movement along a demand curve and a shift of a demand curve. A change in the good’s own price causes a movement along a demand curve. A change in any other relevant factor besides the good’s own price causes a shift of the demand curve. The Demand Function The demand curve shows the relationship between the quantity demanded and a good’s own price, holding other relevant factors constant at some particular levels. We illustrate the effect of a change in one of these other relevant factors by shifting the demand curve. We can represent the same information—information about how price, income, and other variables affect quantity demanded—using a mathematical relationship called the demand function. The demand function shows the effect of all the relevant factors on the quantity demanded. If the factors that affect the amount of avocados demanded include the price of avocados, the price of tomatoes, and income, the demand function, D, can be written as Q = D(p, pt, Y) (2.1) where Q is the quantity of avocados demanded, p is the price of avocados, pt is the price of tomatoes, and Y is the income of consumers. This expression says that the quantity of avocados demanded varies with the price of avocados, the price of tomatoes (which is a substitute product), and the income of consumers. We ignore other factors that are not explicitly listed in the demand function because we assume that they are irrelevant (such as the price of laptop computers) or are held constant (such as the prices of other related goods, tastes, and information). Equation 2.1 is a general functional form—it does not specify a particular form for the relationship between quantity, Q, and the explanatory variables, p, pt, and Y. The estimated demand function that corresponds to the demand curve D1 in Figures 2.1 and 2.2 has a specific (linear) form. If we measure quantity in millions of lbs per month, avocado and tomato prices in dollars per lb, and average monthly income in dollars, the demand function is Q = 104 - 40p + 20pt + 0.01Y. (2.2) When we draw the demand curve D1 in Figures 2.1 and 2.2, we hold pt and Y at specific values. The price per lb for tomatoes is $0.80, and average income is $4,000 per month. If we substitute these values for pt and Y in Equation 2.2, we can rewrite the quantity demanded as a function of only the price of avocados: Q = 104 - 40p + 20pt + 0.01Y = 104 - 40p + (20 * 0.80) + (0.01 * 4,000) = 160 - 40p. (2.3) 14 CHAPTER 2 Supply and Demand The demand function in Equation 2.3 corresponds to the straight-line demand curve D1 in Figure 2.1 with particular fixed values for the price of tomatoes and for income. The constant term, 160, in Equation 2.3 is the quantity demanded (in millions of lbs per month) if the price is zero. Setting the price equal to zero in Equation 2.3, we find that the quantity demanded is Q = 160 - (40 * 0) = 160. Figure 2.1 shows that Q = 160 where D1 hits the quantity axis—where price is zero. Equation 2.3 also shows us how quantity demanded varies with a change in price: a movement along the demand curve. If the price falls from p1 to p2, the change in price, Δp, equals p2 - p1. (The Δ symbol, the Greek letter delta, means “change in” the variable following the delta, so Δp means “change in price.”) If the price of avocados falls from p1 = $2 to p2 = $1.50, then Δp = $1.50 - $2 = -$0.50. Quantity demanded changes from Q1 = 80 at a price of $2 to Q2 = 100 at a price of $1.50, so ΔQ = Q2 - Q1 = 100 - 80 = 20 million lbs per month. More generally, the quantity demanded at p1 is Q1 = D(p1), and the quantity demanded at p2 is Q2 = D(p2). The change in the quantity demanded, ΔQ = Q2 - Q1, in response to the price change (using Equation 2.3) is ΔQ = = = = = Q2 - Q1 D(p2 ) - D(p1 ) (160 - 40p2) - (160 - 40p1) -40(p2 - p1) -40Δp. Thus, the change in the quantity demanded, ΔQ, is -40 times the change in the price, Δp. For example, if Δp = -$0.50, then ΔQ = -40Δp = -40( -0.50) = 20 million lbs. The change in quantity demanded is positive when the price falls, as in this example. This effect is consistent with the Law of Demand. We can see that a 50¢ decrease in price causes a 20 million lb per month increase in quantity demanded. Similarly, raising the price would cause the quantity demanded to fall. Using Calculus Deriving the Slope of a Demand Curve We can determine how the quantity changes as the price increases using calculus. Given the demand function for avocados is Q = 160 - 40p, the derivative of the demand function with respect to price is dQ/dp = -40. Therefore, the slope of the demand curve in Figure 2.1, dp/dQ, is also negative, which is consistent with the Law of Demand. Summing Demand Curves The overall demand for avocados is composed of the demand of many individual consumers. If we know the demand curve for each of two consumers, how do we determine the total demand curve for the two consumers combined? The total quantity demanded at a given price is the sum of the quantity each consumer demands at that price. We can use individual demand curves to determine the total demand of several consumers. Suppose that the demand curve for Consumer 1 is Q1 = D1(p) and the demand curve for Consumer 2 is Q2 = D2(p). 2.2 Supply 15 At price p, Consumer 1 demands Q1 units, Consumer 2 demands Q2 units, and the total quantity demanded by both consumers is the sum of these two quantities: Q = Q1 + Q2 = D1(p) + D2(p). We can generalize this approach to look at the total demand for three, four, or more consumers, or we can apply it to groups of consumers rather than just to individuals. It makes sense to add the quantities demanded only when all consumers face the same price. Adding the quantity Consumer 1 demands at one price to the quantity Consumer 2 demands at another price would not be meaningful for this purpose—the result would not show us a point on the combined demand curve. We illustrate how to combine individual demand curves to get a total demand curve graphically using estimated demand curves of broadband (high-speed) Internet service (Duffy-Deno, 2003). The figure shows the demand curve for small firms (1–19 employees), the demand curve for larger firms, and the total demand curve for all firms, which is the horizontal sum of the other two demand curves. At the current average rate of 40¢ per kilobyte per second (Kbps), the quantity demanded by small firms is Qs = 10 (in millions of Kbps) and the quantity demanded by larger firms is Ql = 11.5. Thus, the total quantity demanded at that price is Q = Qs + Ql = 10 + 11.5 = 21.5. Mini-Case Price, ¢ per Kbps Aggregating the Demand for Broadband Service Small firms’ demand Large firms’ demand 40¢ Qs = 10 Ql = 11.5 Total demand Q = 21.5 Q, Broadband access capacity in millions of Kbps 2.2 Supply Knowing how much consumers want is not enough by itself to tell us what price and quantity will be observed in a market. To determine the market price and quantity, we also need to know how much firms want to supply at any given price. Firms determine how much of a good to supply on the basis of the price of that good and on other factors, including the costs of producing the good. Usually, we expect firms to supply more at a higher price. Before concentrating on the role of price in determining supply, we describe the role of some other factors. Costs of production (how much the firm pays for factors of production such as labor, fuel, and machinery) affect how much of a product firms want to sell. As a firm’s cost falls, it is usually willing to supply more, holding price and other factors constant. Conversely, a cost increase will often reduce a firm’s willingness to produce. If the firm’s cost exceeds what it can earn from selling the good, the firm will 16 CHAPTER 2 Supply and Demand produce nothing. Thus, factors that affect costs also affect supply. If a technological advance allows a firm to produce its good at lower cost, the firm supplies more of that good at any given price, holding other factors constant. Government rules and regulations can also affect supply directly without working through costs. For example, in some parts of the world, retailers may not sell most goods and services on particular days of religious significance. Supply on those days is constrained by government policy to be zero. The Supply Curve The quantity supplied is the amount of a good that firms want to sell at a given price, holding constant other factors that influence firms’ supply decisions, such as costs and government actions. We can show the relationship between price and the quantity supplied graphically. A supply curve shows the quantity supplied at each possible price, holding constant the other factors that influence firms’ supply decisions. Figure 2.3 shows the estimated supply curve, S1, for avocados. As with the demand curve, the price on the vertical axis is measured in dollars per physical unit (dollars per lb), and the quantity on the horizontal axis is measured in physical units per time period (millions of lbs per month). Because we hold fixed other variables that may affect supply, the supply curve concisely answers the question “What happens to the quantity supplied as the price changes, holding all other relevant factors constant?” Effects of Price on Supply. We illustrate how price affects the quantity supplied using the supply curve for avocados in Figure 2.3. The supply curve is upward sloping. As the price increases, firms supply more. If the price is $2 per lb, the quantity supplied by the market is 80 million lbs per month. If the price rises to $3, the quantity supplied rises to 95 million lbs. An increase in the price of avocados causes a movement along the supply curve, resulting in more avocados being supplied. Although the Law of Demand requires that the demand curve slope downward, there is no corresponding “Law of Supply” stating that the supply curve slopes upward. We observe supply curves that are vertical, horizontal, or downward The estimated supply curve, S1, for avocados shows the relationship between the quantity supplied per month and the price per lb, holding constant cost and other factors that influence supply. The upward slope of this supply curve indicates that firms supply more of this good when its price is high and less when the price is low. An increase in the price of avocados causes firms to supply a larger quantity of avocados; any change in price results in a movement along the supply curve. p, $ per lb F IG U RE 2. 3 A Supply Curve 3.00 2.00 Avocado supply curve, S1 0 80 95 Q, Million lbs of avocados per month 2.2 Supply 17 sloping in particular situations. However, supply curves are commonly upward sloping. Accordingly, if we lack specific information about the slope, we usually draw upward-sloping supply curves. Along an upward-sloping supply curve, a higher price leads to more output being offered for sale, holding other factors constant. Effects of Other Variables on Supply. A change in a relevant variable other than the good’s own price causes the entire supply curve to shift. Suppose the price of fertilizer used to produce avocados increases by 55¢ from 40¢ to 95¢ per lb of fertilizer mix. This increase in the price of a key factor of production causes the cost of avocado production to rise. Because it is now more expensive to produce avocados, the supply curve shifts inward or to the left, from S1 to S2 in Figure 2.4. That is, firms want to supply fewer avocados at any given price than before the fertilizer-based cost increase. At a price of $2 per lb for avocados, the quantity supplied falls from 80 million lbs on S1 to 69 million on S2 (after the cost increase). Again, it is important to distinguish between a movement along a supply curve and a shift of the supply curve. When the price of avocados changes, the change in the quantity supplied reflects a movement along the supply curve. When costs or other variables that affect supply change, the entire supply curve shifts. The Supply Function We can write the relationship between the quantity supplied and price and other factors as a mathematical relationship called the supply function. Using a general functional form, we can write the avocado supply function, S, as Q = S(p, pf ), (2.4) where Q is the quantity of avocados supplied, p is the price of avocados, and pf is the price of fertilizer. The supply function, Equation 2.4, might also incorporate other factors such as wages, transportation costs, and the state of technology, but by leaving them out, we are implicitly holding them constant. A 55¢ per lb increase in the price of fertilizer, which is used to produce avocados, causes the supply curve for avocados to shift left from S1 to S2. At the price of avocados of $2 per lb, the quantity supplied falls from 80 on S1 to 69 on S2. p, $ per lb F IG U RE 2. 4 A Shift of a Supply Curve S2, Fertilizer 95¢ per lb S1, Fertilizer 40¢ per lb Effect of a 55¢ increase in the price of fertilizer 2.00 0 69 80 Q, Million lbs of avocados per month 18 CHAPTER 2 Supply and Demand Our estimated supply function for avocados is Q = 58 + 15p - 20pf, (2.5) where Q is the quantity in millions of lbs per month, p is the price of avocados in dollars per lb, and pf is the price of fertilizer in dollars per lb of fertilizer mix. If we hold the fertilizer price fixed at 40¢ per lb, we can rewrite the supply function in Equation 2.5 as solely a function of the avocado price. Substituting pf = $0.40 into Equation 2.5, we find that Q = 58 + 15p - (20 * 0.40) = 50 + 15p. (2.6) What happens to the quantity supplied if the price of avocados increases by Δp = p2 - p1? As the price increases from p1 to p2, the quantity supplied goes from Q1 to Q2, so the change in quantity supplied is ΔQ = Q2 - Q1 = (50 + 15p2) - (50 + 15p1) = 15(p2 - p1) = 15Δp. Thus, a $1 increase in price (Δp = 1) causes the quantity supplied to increase by ΔQ = 15 million lbs per month. This change in the quantity of avocados supplied as p increases is a movement along the supply curve. Summing Supply Curves The total supply curve shows the total quantity produced by all suppliers at each possible price. In the avocado case, for example, the overall market quantity supplied at any given price is the sum of the quantity supplied by Californian producers, the quantity supplied by Mexican producers, and the quantity supplied by producers elsewhere. 2.3 Market Equilibrium The supply and demand curves jointly determine the price and quantity at which a good or service is bought and sold. The demand curve shows the quantities consumers want to buy at various prices, and the supply curve shows the quantities firms want to sell at various prices. Unless the price is set so that consumers want to buy exactly the same amount that suppliers want to sell, either some consumers cannot buy as much as they want or some sellers cannot sell as much as they want. When all market participants are able to buy or sell as much as they want, we say that the market is in equilibrium: a situation in which no participant wants to change its behavior. A price at which consumers can buy as much as they want and sellers can sell as much as they want is called an equilibrium price. At this price the quantity demanded equals the quantity supplied. This quantity is called the equilibrium quantity. Thus, if the government does not intervene in the market, the supplyand-demand model is in equilibrium when the market clears in the sense that buyers and sellers are both able to buy or sell as much as they want at the market price—no one is frustrated and all goods that are supplied to the market are sold. Using a Graph to Determine the Equilibrium To illustrate how supply and demand curves determine the equilibrium price and quantity, we use the avocado example. Figure 2.5 shows the supply curve, S, and demand curve, D, for avocados. The supply and demand curves intersect at point 2.3 Market Equilibrium 19 The intersection of the supply curve, S, and the demand curve, D, for avocados determines the market equilibrium point, e, where p = $2 per lb and Q = 80 million lbs per month. At the lower price of p = $1.60, the quantity supplied is only 74, whereas the quantity demanded is 96, so there is excess demand of 22. At p = $2.40, a price higher than the equilibrium price, there is excess supply of 22 because the quantity demanded, 64, is less than the quantity supplied, 86. When there is excess demand or supply, market forces drive the price back to the equilibrium price of $2. p, $ per lb F IG U RE 2. 5 Market Equilibrium S Excess supply = 22 2.40 Market equilibrium, e 2.00 1.60 Excess demand = 22 D 0 64 74 80 86 96 Q, Million lbs of avocados per month e, the market equilibrium. The equilibrium price is $2 per lb, and the equilibrium quantity is 80 million lbs per month, which is the quantity firms want to sell and the quantity consumers want to buy. Using Algebra to Determine the Equilibrium We can determine the equilibrium mathematically, using algebraic representations of the supply and demand curves. We use these two equations to solve for the equilibrium price at which the quantity demanded equals the quantity supplied (the equilibrium quantity). The demand curve, Equation 2.3, shows the relationship between the quantity demanded, Qd, and the price:5 Qd = 160 - 40p. The supply curve, Equation 2.6, tells us the relationship between the quantity supplied, Qs, and the price: Qs = 50 + 15p. We want to find the equilibrium price, p, at which Qd = Qs = Q. Thus we set the right sides of these two equations equal, 50 + 15p = 160 - 40p, and solve for the price. Adding 40p to both sides of this expression and subtracting 50 from both sides, we find that 55p = 110. Dividing both sides of this last expression by 55, we learn that the equilibrium price is p = $2. We can determine the equilibrium quantity by substituting this p into either the supply equation or the demand equation. Using the demand equation, we find that the equilibrium quantity is Q = 160 - (40 * 2) = 160 - 80 = 80 5Usually, we use Q to represent both the quantity demanded and the quantity supplied. However, for clarity in this discussion, we use Qd and Qs. 20 CHAPTER 2 Supply and Demand million lbs per month. We can obtain the same quantity by using the supply curve equation: Q = 50 + (15 * 2) = 80. Forces That Drive the Market to Equilibrium A market equilibrium is not just an abstract concept or a theoretical possibility. Economic forces cause markets to adjust to the equilibrium. At the equilibrium, price and quantity remain stable until the market is affected by some new event that shifts the demand or supply curve. Remarkably, an equilibrium occurs without any explicit coordination between consumers and firms. In a competitive market such as that for most agricultural products, millions of consumers and thousands of firms make their buying and selling decisions independently. Yet each firm can sell the quantity it wants at the market price and each consumer can buy the quantity he or she wants at that price. It is as though an unseen market force like an invisible hand (a phrase coined by Adam Smith in 1776) directs people to coordinate their activities to achieve equilibrium. What forces cause the market to move to equilibrium? If the price is not at the equilibrium level, consumers or firms have an incentive to change their behavior in a way that will drive the price to the equilibrium level, as we now illustrate. If the price were initially lower than the equilibrium price, consumers would want to buy more than suppliers want to sell. If the price of avocados is $1.60 in Figure 2.5, firms are willing to supply 74 million lbs per month but consumers demand 96 million lbs. At this price, the market is in disequilibrium: the quantity demanded is not equal to the quantity supplied. There is excess demand—the amount by which the quantity demanded exceeds the quantity supplied at a specified price. If the price is $1.60 per lb, there is excess demand of 22 (= 96 - 74) million lbs per month. Some consumers are lucky enough to buy the avocados at $1.60 per lb. Other consumers cannot find anyone who is willing to sell them avocados at that price. What can they do? Some frustrated consumers may offer to pay suppliers more than $1.60 per lb. Alternatively, suppliers, noticing these disappointed consumers, might raise their prices. Such actions by consumers and producers cause the market price to rise. As the price rises, the quantity that firms want to supply increases and the quantity that consumers want to buy decreases. This upward pressure on price continues until it reaches the equilibrium price, $2, where there is no excess demand. If, instead, the price is initially above the equilibrium level, suppliers want to sell more than consumers want to buy. For example, at a price of $2.40, suppliers want to sell 86 million lbs per month but consumers want to buy only 64 million lbs, as Figure 2.5 shows. There is an excess supply—the amount by which the quantity supplied is greater than the quantity demanded at a specified price—of 22 (= 86 - 64) million lbs at a price of $2.40. Not all firms can sell as much as they want. Rather than allow their unsold avocados to spoil, firms lower the price to attract additional customers. As long as the price remains above the equilibrium price, some firms have unsold avocados and want to lower the price further. The price falls until it reaches the equilibrium level, $2, where there is no excess supply and hence no pressure to lower the price further. Not all markets reach equilibrium through the independent actions of many buyers or sellers. In institutionalized or formal markets, such as the Chicago Mercantile Exchange—where agricultural commodities, financial instruments, energy, and metals are traded—buyers and sellers meet at a single location (or on a single Web site). 2.4 Shocks to the Equilibrium 21 Often in these markets certain individuals or firms, sometimes referred to as market makers, act to adjust the price and bring the market into equilibrium very quickly. In summary, at any price other than the equilibrium price, either consumers or suppliers are unable to trade as much as they want. These disappointed market participants act to change the price, driving the price to the equilibrium level. The equilibrium price is called the market clearing price because there are no frustrated buyers and sellers at this price—the market eliminates or clears any excess demand or excess supply. 2.4 Shocks to the Equilibrium Once equilibrium is achieved, it can persist indefinitely because no one applies pressure to change the price. The equilibrium changes only if a shock occurs that shifts the demand curve or the supply curve. These curves shift if one of the variables we were holding constant changes. If tastes, income, government policies, or costs of production change, the demand curve or the supply curve or both may shift, and the equilibrium changes. Effects of a Shift in the Demand Curve Suppose that the price of fresh tomatoes increases by 55¢ per lb, so consumers substitute avocados for tomatoes. As a result, the demand curve for avocados shifts outward from D1 to D2 in panel a of Figure 2.6. At any given price, consumers want more avocados than they did before the price of tomatoes rose. In particular, at the original equilibrium price of avocados of $2, consumers now want to buy 91 million lbs of avocados per month. At that price, however, suppliers still want to sell only 80 million lbs. As a result, there is excess demand of 11 million lbs. Market pressures drive the price up until it reaches a new equilibrium at $2.20. At that price, firms want to sell 83 million lbs and consumers want to buy 83 million lbs, the new equilibrium quantity. Thus, the equilibrium moves from e1 to e2 as a result of the increase in the price of tomatoes. Both the equilibrium price and the equilibrium quantity of avocados rise as a result of the outward shift of the avocado demand curve. Here the increase in the price of tomatoes causes a shift of the demand curve, which in turn causes a movement along the supply curve. Effects of a Shift in the Supply Curve Now suppose that the price of tomatoes stays constant at its original level but the price of fertilizer mix rises by 55¢ per lb. It is now more expensive to produce avocados because the price of an important input, fertilizer, has increased. As a result, the supply curve for avocados shifts to the left from S1 to S2 in panel b of Figure 2.6. At any given price, producers want to supply fewer avocados than they did before the price of fertilizer increased. At the original equilibrium price of avocados of $2 per lb, consumers still want 80 million lbs, but producers are now willing to supply only 69 million lbs, so there is excess demand of 11 million lbs. Market pressure forces the price of avocados up until it reaches a new equilibrium at e2, where the equilibrium price is $2.20 and the equilibrium quantity is 72. The increase in the price of fertilizer causes the equilibrium price to rise but the equilibrium quantity to fall. Here a shift of the supply curve results in a movement along the demand curve. CHAPTER 2 22 Supply and Demand F IG U RE 2. 6 Equilibrium Effects of a Shift of a Demand or Supply Curve (a) A 55¢ per lb increase in the price of tomatoes causes the demand curve for avocados to shift outward from D1 to D2. At the original equilibrium (e1) price of $2, excess demand is 11 million lbs per month. Market pressures drive the price up until it reaches $2.20 at the new equilibrium, (b) Effect of a 55¢ Increase in the Price of Fertilizer S2 p, $ per lb p, $ per lb (a) Effect of a 55¢ Increase in the Price of Tomatoes 2.20 e2. (b) An increase in the price of fertilizer by 55¢ per lb causes producers’ costs to rise, so they supply fewer avocados at every price. The supply curve for avocados shifts to the left from S1 to S2, driving the market equilibrium from e1 to e2, where the new equilibrium price is $2.20. S e2 e2 2.20 e1 S1 e1 2.00 2.00 D2 Excess demand = 11 D D1 Excess demand = 11 0 Q& A 2.1 80 83 91 Q, Million lbs of avocados per month 0 69 72 80 Q, Million lbs of avocados per month Using algebra, determine how the equilibrium price and quantity of avocados change from the initial levels, p = $2 and Q = 80, if the price of fresh tomatoes increases from its original price of pt = 80¢ by 55¢ to $1.35. Answer 1. Show how the demand and supply functions change due to the increase in the price of tomatoes. In the demand function, Equation 2.2, the quantity demanded depends on the price of tomatoes, pt, and income, Y, we set income at its original value, 4,000 to obtain: Q = 104 - 40p + 20pt + 0.01Y = 104 - 40p + 20pt + (0.01 * 4,000) = 144 - 40p + 20pt. (As a check of this equation, when we substitute the original pt = $0.80 into this equation we get Q = 160 - 40p, which is the original demand function, Equation 2.3, that depends on only the price of avocados.) Inserting the new price of tomatoes, $1.35, into this equation, we obtain the new demand equation Q = 144 - 40p + (20 * 1.35) = 171 - 40p. Thus, an increase in the price of tomatoes shifts the intercept of the demand curve, causing the demand curve to shift away from the origin. The supply function does not depend on the price of tomatoes, so the supply function remains the same as in Equation 2.6: Q = 50 + 15p. 2.4 Shocks to the Equilibrium 23 2. Equate the supply and demand functions to determine the new equilibrium. The equilibrium price is determined by equating the right sides of these supply and demand equations: 50 + 15p = 171 - 40p. Solving this equation for p, we find that the equilibrium price of avocados is p = $2.20. We calculate the equilibrium quantity by substituting this price into the supply or demand functions: Q = 50 + (15 * 2.20) = 171 - (40 * 2.20) = 83. 3. Show how the equilibrium price and quantity of avocados changes by subtracting the original values from the new ones. The change in the equilibrium price is Δp = $2.20 - $2 = $0.20. The change in the equilibrium quantity is ΔQ = 83 - 80 = 3. These changes are illustrated in panel a of Figure 2.6. In summary, a change in an underlying factor, such as the price of a substitute or the price of an input, shifts the demand curve or the supply curve. As a result of a shift in the demand or supply curve, the equilibrium changes. To describe the effect of this change, we compare the original equilibrium price and quantity to the new equilibrium values. Ma nagerial I mplication Taking Advantage of Future Shocks A manager with foresight can take advantage of shocks that will adversely affect rivals in the future. In some industries, such as furniture manufacturing, an increase in the cost of fuel (say due to a new carbon tax) hurts some firms and helps others. A higher fuel price would reduce international outsourcing that relies on shipping. For example, when the cost of ocean shipping increased precipitously in 2008 due to high oil costs, many U.S. firms substantially increased their domestic production. The cost of shipping a 40-foot container from Shanghai to the United States rose to $8,000 by 2008 from $3,000 earlier in the decade. (However, the rate fell back to $2,308 in 2011 and to $1,667 in 2012.) According to the Canadian investment bank CIBC World Markets, this increase in shipping costs depressed trade significantly. It caused the foreign supply curve to shift to the left, which in turn caused the total U.S. supply curve (the horizontal sum of the domestic and foreign supply curves) to shift to the left, so that the price of imported furniture in the United States rose. La-Z-Boy, a U.S. domestic furniture manufacturer, benefited from these higher shipping costs. As a La-Z-Boy spokesman observed about the effects of higher shipping costs, “There’s just a handful of us left, but it has become easier for us domestic folks to compete.” Before making business decisions, managers of La-Z-Boy and other domestic firms that face significant foreign competition should use the supply-and-demand model to predict the effects of shocks. For example, if domestic manufacturers expect a new carbon tax to raise fuel costs, they know that the resulting shift of the foreign supply curve for their product will increase the market price, so that they should consider increasing their production capacity. 24 CHAPTER 2 Supply and Demand Effects of Shifts in Both Supply and Demand Curves Some events cause both the supply curve and the demand curve to shift. If both shift, then the qualitative effect on the equilibrium price and quantity may be difficult to predict, even if we know the direction in which each curve shifts. Changes in the equilibrium price and quantity depend on exactly how much the curves shift, as the following Mini-Case and Q&A illustrate. Mini-Case Genetically Modified Foods A genetically modified (GM) food has had its DNA altered through genetic engineering rather than through conventional breeding. The introduction of GM techniques can affect both the supply and demand curves for a crop. The first commercial GM food was Calgene’s Flavr Savr tomato that resisted rotting, which the company claimed could stay on the vine longer to ripen to full flavor. It was first marketed in 1994 without any special labeling. Other common GM crops include canola, corn, cotton, rice, soybean, and sugar cane. Using GM seeds, farmers can produce more output at a given cost. As of 2012, GM food crops, which are mostly herbicide-resistant varieties of corn (maize), soybean, and canola oilseed, were grown in 29 countries but over 40% of the acreage was in the United States. In 2012, the share of GE crops in the United States was 88% for corn, 93% for soybean, and 94% for cotton. Some scientists and consumer groups have raised safety concerns about GM crops. In the European Union (EU), Australia, and several other countries, governments have required labeling of GM products. Although Japan has not approved the cultivation of GM crops, it is the nation with the greatest GM food consumption and does not require labeling. According to some polls, 70% of consumers in Europe object to GM foods. Fears cause some consumers to refuse to buy a GM crop (or the entire crop if GM products cannot be distinguished). In some countries, certain GM foods have been banned. In 2008, the EU was forced to end its de facto ban on GM crop imports when the World Trade Organization ruled that the ban lacked scientific merit and hence violated international trade rules. As of 2013, most of the EU still banned planting most GM crops. Consumers in other countries, such as the United States, are less concerned about GM foods. In yet other countries, consumers may not even be aware of the use of GM seeds. In 2008, Vietnam announced that it was going to start using GM soybean, corn, and cotton seeds to lower food prices and reduce imports. A study found that one-third of crops sampled in Vietnam in 2010 were genetically modified. 2.4 Shocks to the Equilibrium Q&A 2.2 25 When they became available, StarLink and other GM corn seeds caused the supply curve for the corn used for animal feed to shift to the right. If consumer concerns cause the demand curve for corn to shift to the left, how will the before-GM equilibrium compare to the after-GM equilibrium? Consider the possibility that the demand curve may shift only slightly in some countries but substantially in others. Answer 1. Determine the original equilibrium. The original equilibrium, e1, occurs where the before-GM supply curve, S1, intersects the before-GM demand curve, D1, at price p1 and quantity Q1. Both panels a and b of the figure show the same equilibrium. 2. Determine the new equilibrium. When GM seeds are introduced, the new supply curve, S2, lies to the right of S1 in both panels. In panel a, the new demand curve, D2, lies only slightly to the left of D1, while in panel b, D3 lies substantially to the left of D1. In panel a, the new equilibrium e2 is determined by the intersection of S2 and D2. In panel b, the new equilibrium e3 reflects the intersection of D3 and S3 (which is the same as S2 in panel a). 3. Compare the before-GM equilibrium to the after-GM equilibrium. In both panels, the equilibrium price falls from p1 to either p2 or p3. The equilibrium quantity rises from Q1 to Q2 in panel a, but falls from Q1 to Q3 in panel b. 4. Comment. When both curves shift, we cannot predict the direction of change of both the equilibrium price and quantity without knowing how much each curve shifts. Obviously whether growers in a country decide to adopt GM seeds depends crucially on consumerresistance to these new products. (b) Substantial Consumer Concern p1 S1 p, $ per lb p, $ per lb (a) Little Consumer Concern S2 e1 p2 S1 e1 p1 e2 S3 D1 D1 D2 p3 e3 D3 0 Q1 Q2 Q, Tons of corn per month 0 Q3 Q 1 Q, Tons of corn per month 26 CHAPTER 2 2.5 Supply and Demand Effects of Government Interventions Often governments are responsible for changes in market equilibrium. We examine three types of government policies. First, some government actions shift the supply curve, the demand curve, or both curves, which causes the equilibrium to change. Second, the government may use price controls that cause the quantity demanded to differ from the quantity supplied. Third, the government may tax or subsidize a good, which results in a gap between the price consumers pay and that which sellers receive. Policies That Shift Curves Government policies may cause demand or supply curves to shift. Many governments limit who can buy goods. For example, many governments forbid selling cigarettes or alcohol to young people, which decreases the quantity demanded for those goods at each price and thereby shifts their demand curves to the left. Similarly, a government may restrict the amount of foreign products that can be imported, which decreases the quantity supplied of imported goods at each price and shifts the importing country’s supply curve to the left. Or, the government could start buying a good, which increases the quantity demanded at each price for the good and shifts the demand curve to the right. Mini-Case Occupational Licensing Many occupations are licensed in the United States. In those occupations, working without a license is illegal. More than 800 occupations are licensed at the local, state, or federal level, including animal trainers, dietitians and nutritionists, doctors, electricians, embalmers, funeral directors, hair dressers, librarians, nurses, psychologists, real estate brokers, respiratory therapists, salespeople, teachers, and tree trimmers (but not economists). During the early 1950s, fewer than 5% of U.S. workers were in occupations covered by licensing laws at the state level. Since then, the share of licensed workers has grown, reaching nearly 18% by the 1980s, at least 20% in 2000, and 29% in 2008. Licensing is more common in occupations that require extensive education: More than 40% of workers with post-college education are required to have a license compared to only 15% of those with less than a high school education. In some occupations to get licensed one must pass a test, which is frequently designed by licensed members of the occupation. By making the exam difficult, current workers can limit entry. For example, only 42% of people taking the California State Bar Examination in 2011 and in 2012 passed it, although all of them had law degrees. (The national rate for lawyers passing state bar exams in February 2011 was higher, but still only 60%.) To the degree that testing is objective, licensing may raise the average quality of the workforce. However, its primary effect is to restrict the number of workers in an occupation. To analyze the effects of licensing, one can use a graph similar to panel b of Figure 2.6, where the wage is on the vertical axis and the number of workers per year is on the horizontal axis. Licensing shifts the occupational supply curve to the left, reducing the equilibrium quantity of workers and raising the wage. Kleiner and Krueger (2013) found that licensing raises occupational wages by 18%. 2.5 Effects of Government Interventions 27 Price Controls Government policies that directly control the price of a good may alter the market outcome even though they do not affect the demand or supply curves of the good. Such a policy may lead to excess supply or excess demand if the price the government sets differs from the unregulated equilibrium price. We illustrate this result with two types of price control programs. When the government sets a price ceiling at p, the price at which goods are sold may be no higher than p. When the government sets a price floor at p, the price at which goods are sold may not fall below p. Price Ceilings. Price ceilings have no effect if they are set above the equilibrium price that would be observed in the absence of the price controls. If the government says that firms may charge no more than p = $6 per gallon of gas and firms are actually charging p = $4, the government’s price control policy is irrelevant. However, if the unregulated equilibrium price, p, would be above the price ceiling p, the price that is actually observed in the market is the price ceiling. For example, if the equilibrium price of gas would be $4 and a price ceiling of $3 is imposed, then the ceiling price of $3 is charged. Currently, Canada and many European countries set price ceilings on pharmaceuticals. The United States used price ceilings during both world wars, the Korean War, and in 1971–1973 during the Nixon administration, among other times. Hawaii limited the price of wholesale gasoline from 2005–2006. In the aftermath of Hurricane Katrina and the run up in gasoline prices in 2006–2007, and following reports of high oil company profits in 2008, many legislators called for price controls on gasoline, but no legislation was passed. The U.S. experience with gasoline illustrates the effects of price controls. In the 1970s, the Organization of Petroleum Exporting Countries (OPEC) reduced supplies of crude oil (which is converted into gasoline) to Western countries. As a result, the total supply curve for gasoline in the United States shifted to the left from S1 to S2 in Figure 2.7. Because of this shift, the equilibrium price of gasoline would have risen substantially, from p1 to p2. In an attempt to protect consumers by keeping gasoline prices from rising, the U.S. government set price ceilings on gasoline in 1973 and 1979. Restrictions on crude oil production (the major input in producing gasoline) cause the supply curve of gasoline to shift from S1 to S2. In an unregulated market, the equilibrium price would increase to p2 and the equilibrium quantity would fall to Q2. Suppose that the government imposes a price control so that gasoline stations may not charge a price above the price ceiling, p1 = p. At this price, producers are willing to supply only Qs, which is less than the amount Q1 = Qd that consumers want to buy. The result is excessive demand, or a shortage of gasoline of Qd - Qs. p, $ per gallon F IG U RE 2. 7 Price Ceiling on Gasoline S2 S1 e2 p2 e1 p1 = p– Price ceiling D Qs Q2 Q1 = Q d Shortage (Excess demand) Q, Gallons of gasoline per month 28 CHAPTER 2 Supply and Demand The government told gas stations that they could charge no more than p = p1. Figure 2.7 shows the price ceiling as a solid horizontal line extending from the price axis at p. The price control is binding because p2 7 p. The observed price is the price ceiling. At p, consumers want to buy Qd = Q1 gallons of gasoline, which is the equilibrium quantity they bought before OPEC acted. However, firms supply only Qs gallons, which is determined by the intersection of the price control line with S2. As a result of the binding price control, there is excess demand of Qd - Qs. Were it not for the price controls, market forces would drive up the market price to p2, the price at which the excess demand would be eliminated. The government price ceiling prevents this adjustment from occurring. As a result, an enforced price ceiling causes a shortage: a persistent excess demand. At the time of the controls, some government officials argued that the shortages were caused by OPEC’s cutting off its supply of oil to the United States, but that’s not true. Without the price controls, the new equilibrium would be e2. In this equilibrium, the price, p2, is much higher than before, p1; however, there is no shortage. Moreover, without controls, the quantity sold, Q2, is greater than the quantity sold under the control program, Qs. With a binding price ceiling, the supply-and-demand model predicts an equilibrium with a shortage. In this equilibrium, the quantity demanded does not equal the quantity supplied. The reason that we call this situation an equilibrium, even though a shortage exists, is that buyers and sellers who abide by the law do not change their behavior. Without the price controls, consumers facing a shortage would try to get more output by offering to pay more, or firms would raise prices. With effective government price controls, both firms and consumers know that they can’t drive up the price, so they live with the shortage. What happens? Some lucky consumers get to buy Qs units at the low price of p. Other potential customers are disappointed: They would like to buy at that price, but they cannot find anyone willing to sell gas to them. In addition, consumers spend a lot of time waiting in line—a pure waste that adds considerably to the cost of such government interventions. What determines which consumers are lucky enough to find goods to buy at the low price when there are price controls? With enforced price controls, sellers use criteria other than price to allocate the scarce commodity. Firms may supply their friends, long-term customers, or people of a certain race, gender, age, or religion. They may sell their goods on a first-come, first-served basis. Or they may limit everyone to only a few gallons. Another possibility is that firms and customers will try to evade the price controls. A consumer could go to a gas station owner and say, “Let’s not tell anyone, but I’ll pay you twice the price the government sets if you’ll sell me as much gas as I want.” If enough customers and gas station owners behaved that way, no shortage would occur. A study of 92 major U.S. cities during the 1973 gasoline price controls found no gasoline lines in 52 of them. However, in cities such as Chicago, Hartford, New York, Portland, and Tucson, potential customers waited in line at the pump for an hour or more.6 Deacon and Sonstelie (1989) estimated that for every dollar consumers saved due to the 1979 gasoline price controls, they lost $1.16 in waiting time and other factors. 6See MyEconLab Chapter Resources, Chapter 2, “Gas Lines,” for a discussion of the effects of the 1973 and 1979 gasoline price controls. 2.5 Effects of Government Interventions Mini-Case Disastrous Price Controls 29 Robert G. Mugabe, who has ruled Zimbabwe with an iron fist for nearly three decades, has used price controls to try to stay in power by currying favor among the poor.7 In 2001, he imposed price controls on many basic commodities, including food, soap, and cement, which led to shortages of these goods and a thriving black, or parallel, market in which the controls were ignored developed. Prices on the black market were two or three times higher than the controlled prices. He imposed more extreme controls in 2007. A government edict cut the prices of 26 essential items by up to 70%, and a subsequent edict imposed price controls on a much wider range of goods. Gangs of price inspectors patrolled shops and factories, imposing arbitrary price reductions. State-run newspapers exhorted citizens to turn in store owners whose prices exceeded the limits. The Zimbabwean police reported that they arrested at least 4,000 businesspeople for not complying with the price controls. The government took over the nation’s slaughterhouses after meat disappeared from stores, but in a typical week, butchers killed and dressed only 32 cows for the entire city of Bulawayo, which consists of 676,000 people. Ordinary citizens initially greeted the price cuts with euphoria because they had been unable to buy even basic necessities because of hyperinflation and past price controls. Yet most ordinary citizens were unable to obtain much food because most of the cut-rate merchandise was snapped up by the police, soldiers, and members of Mr. Mugabe’s governing party, who were tipped off prior to the price inspectors’ rounds. Manufacturing slowed to a crawl because firms could not buy raw materials and because the prices firms received were less than their costs of production. Businesses laid off workers or reduced their hours, impoverishing the 15% or 20% of adult Zimbabweans who still had jobs. The 2007 price controls on manufacturing crippled this sector, forcing manufacturers to sell goods at roughly half of what it cost to produce them. By mid-2008, the output by Zimbabwe’s manufacturing sector had fallen 27% compared to the previous year. As a consequence, Zimbabweans died from starvation. Although we have no exact figures, according to the World Food Program, over five million Zimbabweans faced starvation in 2008. Aid shipped into the country from international relief agencies and the two million Zimbabweans who fled abroad helped keep some people alive. In 2008, the World Food Program made an urgent appeal for $140 million in donations to feed Zimbabweans, stating that drought and political upheaval would soon exhaust the organization’s stockpiles. Thankfully, the price controls were lifted in 2009. Price Floors. Governments also commonly use price floors. One of the most important examples of a price floor is a minimum wage in a labor market. A minimum wage law forbids employers from paying less than the minimum wage, w. 7Mr. Mugabe justified price controls as a means to deal with profiteering businesses that he said were part of a Western conspiracy to re-impose colonial rule. Actually, they were a vain attempt to slow the hyperinflation that resulted from his printing Zimbabwean money rapidly. Prices increased several billion times in 2008, and the government printed currency with a face value of 100 trillion Zimbabwe dollars. 30 CHAPTER 2 Supply and Demand Minimum wage laws date from 1894 in New Zealand, 1909 in the United Kingdom, and 1912 in Massachusetts. The Fair Labor Standards Act of 1938 set a federal U.S. minimum wage of 25¢ per hour. The U.S. federal minimum hourly wage rose to $7.25 in 2009 and remained at that level through early 2013, but 19 states have higher state minimum wages. (State and federal minimum wages are listed at www.dol.gov). The minimum wage in Canada differs across provinces, ranging from C$9.50 to C$11.00 (where C$ stands for Canadian dollars) in 2012. See www.fedee.com/minwage.html for minimum wages in European countries. If the minimum wage is binding—that is, if it exceeds the equilibrium wage, w * —it creates unemployment: a persistent excess supply of labor. We illustrate the effect of a minimum wage law in a labor market in which everyone is paid the same wage. Figure 2.8 shows the supply and demand curves for labor services (hours worked). Firms buy hours of labor service by hiring workers. The quantity measure on the horizontal axis is hours worked per year, and the price measure on the vertical axis is the wage per hour. With no government intervention, the market equilibrium is e, where the wage is w * and the number of hours worked is L *. The minimum wage creates a price floor, a horizontal line, at w. At that wage, the quantity demanded falls to Ld and the quantity supplied rises to Ls. As a result, there is an excess supply of labor of Ls - Ld. The minimum wage prevents market forces from eliminating this excess supply, so it leads to an equilibrium with unemployment. The original 1938 U.S. minimum wage law, which was set much higher than the equilibrium wage in Puerto Rico, caused substantial unemployment there. It is ironic that a law designed to help workers by raising their wages may harm some of them by causing them to become unemployed. A minimum wage law benefits only those workers who remain employed.8 In the absence of a minimum wage, the equilibrium wage is w * and the equilibrium number of hours worked is L *. A minimum wage, w, set above w *, leads to unemployment—persistent excess supply—because the quantity demanded, Ld, is less than the quantity supplied, Ls. w, Wage per hour F IG U RE 2. 8 Minimum Wage: A Price Floor S w — Minimum wage, price floor e w* D Ld L* Ls L, Hours worked per year Unemployment (Excess Supply) 8The minimum wage could raise the wage enough that total wage payments, wL, rise despite the fall in demand for labor services. If the workers could share the unemployment—everybody works fewer hours than he or she wants—all workers could benefit from the minimum wage. Card and Krueger (1995) have argued, based on alternatives to the simple supply-and-demand model, that minimum wage laws raise wages in some markets (such as fast foods) without significantly reducing employment. In contrast, Neumark and Wascher (2008) conclude, based on an extensive review of minimum wage research, that increases in the minimum wage often have negative effects on employment. 2.5 Effects of Government Interventions 31 Why Supply Need Not Equal Demand. The price ceiling and price floor examples show that the quantity supplied does not necessarily equal the quantity demanded in a supply-and-demand model. The quantity supplied need not equal the quantity demanded because of the way we define these two concepts. The quantity supplied is the amount sellers want to sell at a given price, holding other factors that affect supply, such as the price of inputs, constant. The quantity demanded is the quantity that buyers want to buy at a given price, if other factors that affect demand are held constant. The quantity that sellers want to sell and the quantity that buyers want to buy at a given price need not equal the actual quantity that is bought and sold. When the government imposes a binding price ceiling of p on gasoline, the quantity demanded is greater than the quantity supplied. Despite the lack of equality between the quantity supplied and the quantity demanded, the supply-and-demand model is useful in analyzing this market because it predicts the excess demand that is actually observed. We could have defined the quantity supplied and the quantity demanded so that they must be equal. If we were to define the quantity supplied as the amount firms actually sell at a given price and the quantity demanded as the amount consumers actually buy, supply must equal demand in all markets because the quantity demanded and the quantity supplied are defined to be the same quantity. This distinction is important because many people, including politicians and newspaper reporters, are confused on this point. Someone insisting that “demand must equal supply” must be defining supply and demand as the actual quantities sold. Because we define the quantities supplied and demanded in terms of people’s wants and not actual quantities bought and sold, the statement that “supply equals demand” is a theory, not merely a definition. This theory says that the price and quantity in a market are determined by the intersection of the supply curve and the demand curve, and the market clears if the government does not intervene. However, the theory also tells us that government intervention can prevent market-clearing. For example, the supply-and-demand model predicts that excess demand will arise if the government imposes a price ceiling below the market-clearing price or excess supply if the government imposes a price floor above the market-clearing price. Sales Taxes Governments frequently impose sales taxes on goods, such as the carbon tax discussed at the beginning of the chapter. Sales taxes typically raise the price that consumers pay for a good and lower the price that firms receive for it. A common sales tax is the specific tax, where a specified dollar amount, t, is collected per unit of output. For example, the federal government collects t = 18.4¢ on each gallon of gas sold in the United States.9 In this section, we examine three questions about the effects of a specific tax: 1. What effect does a specific tax have on equilibrium prices and quantity? 2. Do the equilibrium price and quantity depend on whether the tax is assessed on consumers or on producers? 3. Is it true, as many people claim, that taxes are fully passed through to consumers? That is, do consumers pay the entire tax imposed on suppliers (or on consumers)? 9The other major sales tax is an ad valorem tax, where the government collects a percentage of the price that consumers pay. The analysis of ad valorem taxes is similar to the analysis of specific taxes. 32 CHAPTER 2 Supply and Demand Equilibrium Effects of a Specific Tax. To answer these three questions, we must extend the standard supply-and-demand analysis to take taxes into account. We can illustrate the effect of a specific tax on the avocado market equilibrium. Suppose that the government collects a specific tax of t = $0.55 per lb of avocados from sellers at the time of sale. If consumers pay p, suppliers receive p - t = p - $0.55, and the government keeps t = $0.55. Before the tax, the intersection of the before-tax avocado demand curve D and the before-tax avocado supply curve S1 in panel a of Figure 2.9 determines the before-tax equilibrium, e1, where the equilibrium price is p1 = $2, and the equilibrium quantity is Q1 = 80. After the tax, firms only keep $1.45 out of the $2 they receive, so they are not willing to supply as many avocados as before the tax. For firms to be willing to sell 80 units after the tax, the firms would have to receive $2.55 before the tax so that they could keep $2. As a result, the after-tax supply curve, S2, is t = $0.55 above the original supply curve S1 at every quantity, as the figure shows. The after-tax equilibrium e2 is determined by the intersection of S2 and the demand curve D, where consumers pay p2 = $2.15, firms receive p2 - t = p2 - $0.55 = $1.60, and Q2 = 74. Thus, the answer to our first question is that the specific tax causes the equilibrium price consumers pay to rise, the equilibrium quantity that firms receive to fall, and the equilibrium quantity to fall. Although the consumers and producers are worse off because of the tax, the government acquires new tax revenue of $0.55 per lb * 74 million lbs per year = $40.7 million per month. The Same Equilibrium No Matter Who Is Taxed. Does it matter whether the specific tax is collected from firms or consumers? No: The market outcome is the same regardless of who is taxed. The amount consumers pay, p + t, is the price that firms receive, p, plus the tax, t, that the government collects. Thus, if the final price that consumers pay including the tax is $2, the price that suppliers receive is only $1.45. Consequently, the demand curve as seen by firms shifts downward by $0.55 from D1 to D2 in panel b of Figure 2.9. The new equilibrium e2 occurs where D2 intersects the supply curve S. The equilibrium quantity, Q2, is 74. The equilibrium price, p2, is $1.60, the price firms receive. Consumers pay p2 + $0.55 = $2.15. Thus, the market outcome is the same as in panel a where the tax is collected from firms.10 Pass-Through. Many people believe that if a tax is imposed on firms they simply raise their price by the amount of the tax—that the tax is fully passed through to consumers. This belief is not true in general. Full pass-through can occur, but partial pass-through is more common. As we just showed for the avocado market in panel a of Figure 2.9, the price consumers pay rises from $2 to $2.15 after a 55¢ specific tax is imposed on firms. Thus, the firms shift only 15¢ of the 55¢ tax to consumers. The firms absorb 40¢ of the tax, because the price that firms receive falls from $2 to $1.60. Thus, the fraction of the tax that consumers pay is 15/55 = 3/11 and the fraction that firms absorb is 40/55 = 8/11. As panel b shows, the allocation of the tax is the same if it is collected from consumers rather than firms. However, as the following Q&A shows, the degree of the pass-through depends on the shapes of the supply and demand curves. 10This analysis assumes that there is no administrative cost to collecting a tax. If collecting a tax from consumers required more resources than collecting taxes from sellers, then the overall economic impact of a tax on consumers differs from the impact of a tax on sellers. 2.5 Effects of Government Interventions 33 F IG U RE 2. 9 Effect of a 55¢ Specific Tax on the Avocado Market Collected from Producers (a) A specific tax of t = $0.55 per lb collected from producers shifts the before-tax avocado supply from S1 to the after-tax supply curve, S2. The tax causes the equilibrium to shift from e1 (the intersection of S1 and D) to e2 (intersection of S2 and D). The equilibrium price, which consumers pay, increases from $2 to $2.15, while the price firms receive falls from $2 to $1.60 (= $2.15 - $0.55). (b) Tax Collected from Consumers S2 e2 p1 = 2.00 p, $ per lb p, $ per lb (a) Tax Collected from Firms p2 = 2.15 (b) A specific tax collected from consumers shifts the before-tax avocado demand curve from D1 to the aftertax demand curve, D2. Consequently, the equilibrium shifts from e1 (intersection of D1 and S) to e2 (intersection of D2 with S). The new prices and quantity are the same as those when the tax is collected from firms. S1 t = $0.55 p2 + t = 2.15 e1 e1 p1 = 2.00 D p2 – t = 1.60 S p2 = 1.60 e2 D1 t = $0.55 D2 0 Q2 = 74 Q1 = 80 Q, Million lbs of avocados per month p, Price per unit Q& A 2.3 p1 p2 = p1 – 1 0 Q2 = 74 Q1 = 80 Q, Million lbs of avocados per month If the supply curve is vertical and demand is linear and downward sloping, what is the effect of a $1 specific tax collected from consumers on equilibrium price and quantity, and what share of the tax is paid for by consumers? Why? Answer 1. Determine the equilibrium in the absence of a tax. The supply curve, S in the graph, is vertical at Q1 indicating that suppliers will supply Q1 to the market at any price. The before-tax, downward-sloping linear demand curve, D1, intersects S at the before-tax equilibrium, e1, where the price is p1 and the quantity is Q1. 2. Show how the tax shifts the demand curve and determine the new equilibrium. A specific tax S of $1 shifts the before-tax demand curve downward by $1 to D2. The intersection of e1 D2 and S determines the after-tax equilibrium, e2, where the price firms receive is 1 p2 = p1 - 1, the price consumers pay after tax D $1 is p1 = p2 + 1, and the quantity is Q2 = Q1. e2 3. Compare the before- and after-tax equilibria. The 2 specific tax doesn’t affect the equilibrium quanD tity or the tax-inclusive price that consumers pay, but it lowers the price that firms receive Q 1 = Q2 by the full amount of the tax. Thus, there is no Q, Quantity per time period pass-through of the tax to consumers. Thus, 34 CHAPTER 2 Supply and Demand even though the tax is collected from consumers, consumers pay the same price whether the tax is imposed or not because the price received by firms falls by the amount of the tax. 4. Explain why. The reason firms must absorb the entire tax is that, because the supply curve is vertical, the firms sell the same quantity no matter the price. Consumers will not buy that quantity unless their after-tax price is the same as the before-tax price. Therefore, the final price to consumers cannot change and firms must absorb the tax: There is no pass-through. For example, suppose that firms at a farmers’ market have a fixed amount of melons that will spoil if they are not sold on this day. The firms sell the melons for the most they can get ( p2 in the figure) because if they do not sell the melons, they are worthless. Consequently, the farmers must absorb the entire tax or be left with unsold melons. Ma nagerial I mplication Cost Pass-Through 2.6 Managers should use pass-through analysis to predict the effect on their price and quantity from not just a new tax but from any per unit increase in costs. That is, if the cost of producing avocados rises 55¢ per lb because of an increase in the cost of labor or other factor of production, rather than because of a tax, the same analysis as in panel a of Figure 2.9 would apply, so a manager would know that only 15¢ of this cost increase could be passed through to consumers. When to Use the Supply-and-Demand Model As we have seen, the supply-and-demand model can help us to understand and predict real-world events in many markets. As with many models, the supply-anddemand model need not be perfect to be useful. It is much like a map. A map can leave out many details and still be very valuable—indeed, maps are useful in large part because they simplify reality. Similarly, the supply-and-demand model gains much of its power from its simplicity. The main practical question concerns whether the model is close enough to reality to yield useful predictions and conclusions. We have learned that the supply-and-demand model provides a very good description of actual events in highly competitive markets. It is precisely accurate in perfectly competitive markets, which are markets in which all firms and consumers are price takers: no market participant can affect the market price. Perfectly competitive markets have five characteristics that result in price taking by firms: (1) many buyers and sellers transact in a market, (2) all firms produce identical products, (3) all market participants have full information about price and product characteristics, (4) transaction costs are negligible, and (5) firms can easily enter and exit the market over time. In a market with a very large number of sellers, no single producer or consumer is a large enough part of the market to affect the price. The more firms in a market, the 2.6 When to Use the Supply-and-Demand Model 35 less any one firm’s output affects total market output and hence the market price. If one of the many thousands of wheat farmers stops selling wheat, the price of wheat will not change. Similarly, no individual buyer of wheat can cause price to change through a change in buying patterns. If consumers believe all firms produce identical products, consumers do not prefer one firm’s good to another’s. Thus, if one firm raised its price, consumers would all buy from the other firm. If consumers know the prices all firms charge and one firm raises its price, that firm’s customers will buy from other firms. If consumers have less information about product quality than a firm, the firm can take advantage of consumers by selling them inferior-quality goods or by charging a much higher price than that charged by other firms. In such a market, the observed price may be higher than that predicted by the supply-and-demand model, the market may not exist at all (consumers and firms cannot reach agreements), or different firms may charge different prices for the same good. If it is cheap and easy for a buyer to find a seller and make a trade, and if one firm raises its price, consumers can easily arrange to buy from another firm. That is, perfectly competitive markets typically have very low transaction costs: the expenses, over and above the price of the product, of finding a trading partner and making a trade for the product. These costs include the time and money spent gathering information on quality and finding someone with whom to trade. The costs of traveling and the value of the consumer’s time are transaction costs. Other transaction costs may include the costs of writing and enforcing a contract, such as the cost of a lawyer’s time. If transaction costs are very high, no trades at all might occur. In less extreme cases individual trades may occur, but at a variety of prices. The ability of firms to enter and exit a market freely leads to a large number of firms in a market and promotes price taking. Suppose a firm could raise its price and make a higher profit. If other firms could not enter the market, this firm would not be a price taker. However, if other firms can quickly and easily enter the market, the higher profit will encourage entry until the price is driven back to the original level. In markets without these characteristics, firms may not be price takers. For example, if there is only one seller of a good or service—a monopoly—that seller is a price setter and can affect the market price. Because demand curves slope downward, a monopoly can increase the price it receives by reducing the amount of a good it supplies. Firms are also price setters in an oligopoly—a market with only a small number of firms. In markets with price setters, the market price is usually higher than that predicted by the supply-and-demand model. That does not make the model wrong. It means only that the supply-and-demand model might not be the right tool to analyze markets with a small number of buyers and/or sellers. In such markets, we use other models. As a practical matter, it is rare that we would find a market that fully and completely satisfies all the conditions needed for perfect competition. The practical issue concerns whether the market is “competitive enough” for the supply-and-demand model to be useful in the sense that it accurately describes the market and can be used to predict the effects of changes to the equilibrium. Experience has shown that the supply-and-demand model is reliable in a wide range of markets, such as those for agriculture, financial products, labor, construction, many services, real estate, wholesale trade, and retail trade. 36 CHAPTER 2 Ma nagerial So l ution (a) Long-Run Gasoline Market (b) Short-Run Gasoline Market p, ¢ per gallon We conclude our analysis of the supply-and-demand model by returning to the managerial problem posed in the introduction of this chapter: What will be the effect of imposing a carbon tax on the price of gasoline? The primary targets of carbon taxes are fossil fuels such as oil, natural gas, and coal. These fuels release carbon-based pollutants—including greenhouse gases that contribute to global warming—into the environment. Typically, a carbon tax is a specific tax on the amount of carbon produced by consuming fuels or other products. Currently, the carbon tax in Sweden is $150 per ton of carbon. Because the amount of carbon in a gallon or liter of gasoline is fixed, effectively, a carbon tax is a specific tax on gasoline. Consequently, we can analyze the impact of a carbon tax on gasoline in the same way that we analyzed the effect of a specific tax on avocados. A good manager considers the short-run and long-run price effects of a tax, which are likely to differ. As we’ve already seen, the degree to which a tax is passed through to consumers depends on the shapes of the demand and supply curves. Typically, short-run supply and demand curves differ from the long-run curves. In particular, the long-run supply curve of gasoline differs substantially from the short-run curve. In the long-run, the supply curve is upward sloping, as in our typical figure. However, the U.S. short-run supply curve of gasoline is very close to vertical. The U.S. refinery capacity has fallen over the last quarter century. Currently the 149 U.S. refineries can process a maximum of only 17.3 million barrels of crude oil per day, compared to 1981 when 324 refineries could process 18.6 million barrels per day. Refineries operate at almost full capacity during the summer, when the gasoline demand curve shifts to the right because families take long car trips during their vacations. Consequently, refineries cannot increase their output in the short run, and the supply curve for gasoline is nearly vertical at the maximum capacity, Q. That is, even if the price of gasoline rises, producers sell no more gasoline than Q. From empirical studies, we know that the U.S. federal gasoline specific tax of t = 18.4¢ per gallon is shared roughly equally between gasoline companies and p, ¢ per gallon Carbon Taxes Supply and Demand S LR S SR S LR p2 + t = p1 p2 + t p1 e1 e1 e2 p2 p2 e2 D1 D1 D2 Q Q, Gallons of gasoline per day D2 Q Q, Gallons of gasoline per day Summary 37 consumers in the long run. However, based on what we learned from Q&A 2.3, we expect that most of the tax will fall on firms that sell gasoline in the short run. We contrast the long-run and short-run effects of a carbon tax in the figure. In both panels, the carbon tax is equivalent to a specific gasoline tax of t per gallon. If this tax is collected from consumers, the before-tax demand curve D1 shifts down by t to the after-tax demand curve D2. Also in both panels, the equilibrium shifts from e1—the intersection of D1 and the relevant supply curve—to e2—the intersection of D2 and the relevant supply curve (though these equilibrium points are not the same across the two panels). Panel a shows the effect of the tax in the long run, where the long-run supply curve is upward sloping. The price that firms receive falls from p1 to p2, and the price that consumers pay rises from p1 to p2 + t. As the figure illustrates, the tax is roughly equally shared by consumers and firms in the long run. In the short run in panel b, the upward-sloping short-run supply curve becomes vertical at full capacity, Q. The price that consumers pay, p1, is the same before the tax and after the tax. That is, the price that gasoline firms receive, p2, falls by the full amount of the tax. Manufacturing and other firms that ship goods are consumers of gasoline. They can expect to absorb relatively little of a carbon tax when it is first imposed, but half of the tax in the long run.11 11An alternative approach to using a carbon tax to control pollution is for the government to restrict emissions directly. Each firm is given a fixed number of emission permits, where each permit allows the owner to release a given quantity of emissions. A market-based variant allows firms to buy or sell these emission permits in a market. The resulting price of an emission permit acts much like a tax on emissions. See Chapter 16. S U M MARY 1. Demand. The quantity of a good or service de- 2. Supply. The quantity of a good or service supplied manded by consumers depends on the price of a good, the price of goods that are substitutes and complements, consumers’ incomes, the information they have about the good, their tastes, government regulations, and other factors. The Law of Demand—which is based on observation—says that demand curves slope downward: the higher the price, the less quantity of the good demanded, holding constant other factors that affect demand. A change in price causes a movement along the demand curve. A change in income, tastes, or another factor that affects demand other than price causes a shift of the demand curve. To get a total demand curve, we horizontally sum the demand curves of individuals or other subgroups of consumers. That is, we add the quantities demanded by each individual at a given price to get the total quantity demanded. by firms depends on the price, costs of inputs, the state of technology, government regulations, and other factors. The market supply curve usually but not always slopes upward. A change in price causes a movement along the supply curve. A change in the price of an input or in technology causes a shift of the supply curve. The total supply curve is the horizontal sum of the supply curves for individual firms. 3. Market Equilibrium. Equilibrium arises when no market participant has an incentive to change its behavior. In an unregulated supply-and-demand model, the market equilibrium is a point: a price and a quantity. The market equilibrium is determined by the intersection of the supply curve and demand curve. At the equilibrium price, the market for the good clears in the sense that the quantity of the good demanded by consumers exactly 38 CHAPTER 2 Supply and Demand equals the quantity of the good that suppliers supply to the market, which is the equilibrium quantity. The actions of buyers and sellers put pressure on price and quantity to move toward equilibrium levels if the market price is initially too low or too high. less than the quantity demanded, leading to persistent excesses or shortages. A specific tax, a type of sales tax, typically lowers the equilibrium quantity, raises the price paid by consumers, and lowers the price received by sellers, so firms are unable to pass the entire tax through to consumers. 4. Shocks to the Equilibrium. A change in an 6. When to Use the Supply-and-Demand Model. The supply-and-demand model is a pow- underlying factor other than a good’s own price causes a shift of the supply curve or the demand curve, which alters the equilibrium. For example, if the price of coffee rises, we would expect the demand for tea, a substitute, to shift outward, putting upward pressure on the price of tea and leading to an increase in the quantity of tea sold. 5. Effects of Government Interventions. Some government policies—such as restrictions on who can buy a product—cause a shift in the supply or demand curves, thereby altering the equilibrium. Other government policies, such as price controls, can cause the quantity supplied to be greater or erful tool used to explain what happens in a market and to make predictions about what will happen if an underlying factor changes. This model accurately predicts what occurs in some markets but not others. The supply-and-demand model performs best in explaining and predicting the behavior of markets with many buyers and sellers, with identical or at least very similar products provided by different producers, with free entry and exit by producers, with full information about price and other market characteristics, and with low transaction costs. Q U E S T ION S All exercises is available on MyEconLab; * = answer at the back of this book. 1. Demand *1.1. Does an increase in average income cause a shift of the demand curve for avocados or a movement along the demand curve? Explain briefly. 1.2. Given the estimated demand function Equation 2.2 for avocados, Q = 104 - 40p + 20pt + 0.01Y, use algebra (or calculus) to show how the demand curve shifts as per capita income, Y, increases by $1,000 a year. Illustrate this shift in a diagram. 1.3. Assume that both the U.S. and Canadian demand curves for lumber are linear. The Canadian demand curve lies inside the U.S. curve (the Canadian demand curve hits the axes at a lower price and a lower quantity than the U.S. curve). Draw the individual country demand curves and the aggregate demand curve for the two countries. Explain the relationship between the country and aggregate demand curves in words. *1.4. The demand curve for a truckload of firewood for college students in a small town is Qc = 400 - p. It is sometimes convenient to rewrite a demand curve equation with price on the left side. We refer to such a relationship as the inverse demand function. Therefore, the inverse demand curve for college students is p = 400 - Qc. The demand curve for other town residents is Qr = 400 - 2p. a. What is the inverse demand curve for other town residents? b. At a price of $300, will any firewood be sold to college students? What about other town residents? At what price is the quantity demanded by other town residents zero? c. Draw the total demand curve, which aggregates the demand curves for college students and other residents. 2. Supply 2.1. Use Equation 2.5, the estimated supply function for avocados, Q = 58 + 15p - 20pf , to determine how much the supply curve for avocados shifts if the price of fertilizer rises by $1.10 per lb. Illustrate this shift in a diagram. *2.2. Explain why a change in the price of fertilizer causes a shift in the supply curve for avocados rather than a movement along the supply curve for avocados. *2.3. Holding the price of fertilizer constant, by how much would the price of avocados need to rise to cause an increase of 60 million lbs per month in the quantity of avocados supplied? 2.4. The total U.S. supply curve for frozen orange juice is the sum of the supply curve from Florida and the imported supply curve from Brazil. In a diagram, Questions show the relationship between these three supply curves and explain it in words. 3. Market Equilibrium *3.1. A large number of firms are capable of producing chocolate-covered cockroaches. The linear, upwardsloping supply curve starts on the price axis at $6 per box. A few hardy consumers are willing to buy this product (possibly to use as gag gifts). Their linear, downward-sloping demand curve hits the price axis at $4 per box. Draw the supply and demand curves. Does an equilibrium occur at a positive price and quantity? Explain your answer. 3.2. The demand curve is Q = 100 - p, and the supply curve is Q = 20 + 3p. What are the equilibrium price and quantity? 3.3. Using the supply and demand functions for avocados in the chapter, derive the demand and supply curves if pt = $0.80, Y = $4,000, and pf = $0.95. What is the equilibrium price and quantity of avocados? 4. Shocks to the Equilibrium 4.1. Using supply-and-demand diagrams, illustrate and explain the effect of an outward shift in the demand curve on price and quantity if a. The supply curve is horizontal. b. The supply curve is vertical. c. The supply curve is upward sloping. 4.2. Use supply-and-demand diagrams to illustrate the qualitative effect of the following possible shocks on the U.S. avocado market. a. A new study shows significant health benefits from eating avocados. b. Trade barriers that restricted avocado imports from Mexico are eliminated (“Free Trade Party Dip,” Los Angeles Times, February 6, 2007). c. A recession causes a decline in per capita income. d. Genetically modified avocado plants that allow for much greater output or yield without increasing cost are introduced into the market. *4.3. The United States is increasingly outsourcing jobs to India: having the work done in India rather than in the United States. For example, the Indian firm Tata Consultancy Services, which provides information technology services, increased its work force by 70,000 workers in 2010 and expected to add 60,000 more in 2011 (“Outsourcing Firm Hiring 60,000 Workers in India,” San Francisco Chronicle, June 16, 2011). As a result of increased outsourcing, wages of some groups of Indian skilled workers have increased substantially over the years. Use a supplyand-demand diagram to explain this outcome. 39 4.4. In Q&A 2.1, if the price of tomatoes rises to $1.80 per lb, what are the new equilibrium price and quantity for avocados? 4.5. According to Borjas (2003), immigration into the United States increased the labor supply of working men by 11.0% from 1980 to 2000 and reduced the wage of the average native U.S. worker by 3.2%. Draw a supply-and-demand diagram and label the axes to illustrate what happened. 4.6. Given that the U.S. supply of frozen orange juice comes mainly from Florida and Brazil, what effect would a freeze that damages oranges in Florida have on the price and quantity of frozen orange juice sold in the United States? What effect would the freeze have on the price of grapefruit juice? Use supply-and-demand diagrams in your answer. 4.7. Ethanol, a fuel, is made from corn. Ethanol production increased 15.4 times from 1990 to 2011 (www .ethanolrfa.org, January 2013). What effect did this increased use of corn for producing ethanol have on the price of corn and the consumption of corn as food? Illustrate using a supply-and-demand diagram. 4.8. The major BP oil spill in the Gulf of Mexico substantially reduced the harvest of shrimp and other seafood in the Gulf, but had limited impact on the prices that U.S. consumers paid in 2010 (Emmeline Zhao, “Impact on Seafood Prices Is Limited,” Wall Street Journal, June 20, 2010). The reason was that the United States imports about 83% of its seafood and only 2% of domestic supplies come from the Gulf. Use a supply-and-demand diagram to illustrate what happened. 4.9. Increasingly, instead of advertising in newspapers, individuals and firms use Web sites that offer free or inexpensive classified ads, such as ClassifiedAds .com, Craigslist.org, Realtor.com, Jobs.com, Monster.com, and portals like Google and Yahoo. Using a supply-and-demand model, explain what will happen to the equilibrium levels of newspaper advertising as the use of the Internet grows. Will the growth of the Internet affect the supply curve, the demand curve, or both? Why? *4.10. Humans who consume beef products made from diseased animal parts can develop mad cow disease (bovine spongiform encephalopathy, or BSE, a new variant of Creutzfeldt-Jakob disease), a deadly affliction that slowly eats holes in sufferers’ brains. The first U.S. case, in a cow imported from Canada, was reported in December 2003. As soon as the United States revealed the discovery of the single mad cow, more than 40 countries slapped an embargo on U.S. beef, causing beef supply curves to shift to the left in those importing countries. At 40 CHAPTER 2 Supply and Demand least initially, a few U.S. consumers stopped eating beef, causing the demand curve in the United States to shift slightly to the left. (Schlenker and VillasBoas, 2009, found that U.S. consumers regained confidence and resumed their earlier levels of beef buying within three months.) In the first few weeks after the U.S. ban, the quantity of beef sold in Japan fell substantially, and the price rose. In contrast, in January 2004, three weeks after the first discovery, the U.S. price fell by about 15% and the quantity sold increased by 43% over the last week in October 2003. Use supply-and-demand diagrams to explain these events. 4.11. In the previous question, you were asked to illustrate why the mad cow disease announcement initially caused the U.S. equilibrium price of beef to fall and the quantity to rise. Show that if the supply and demand curves had shifted in the same directions as above but to greater or lesser degrees, the equilibrium quantity might have fallen. Could the equilibrium price have risen? (Hint: See Q&A 2.2.) *4.12. Increases in the price of petroleum affect the demand curve for aluminum. Petroleum-based chemicals (petrochemicals) are the main raw material used for plastic. Plastics are used to make many products, including beverage containers, auto parts, and construction materials. An alternative to plastic in these (and other) uses is aluminum. Thus, plastic and aluminum are substitutes. An increase in petroleum prices increases the cost of petrochemicals. Petroleum prices also affect the supply curve for aluminum. Increases in petroleum prices tend to raise energy prices, including electricity prices. Electricity is a very important input in producing aluminum. Therefore, increasing petroleum prices tend to increase the cost of electricity. In a supply-and-demand diagram, show how an increase in petroleum prices affects the demand curve and supply curve for aluminum. If the price of petroleum rises, would the price of aluminum rise, fall, remain unchanged, or is the result indeterminate? Would the quantity of aluminum sold rise, fall, remain unchanged, or is the result indeterminate? Explain your answers. 5. Effects of Government Interventions 5.1. Use a supply-and-demand diagram to show the effects of occupational licensing on the equilibrium wage and number of workers in an occupation as described in the Mini-Case “Occupational Licensing.” *5.2. After Katrina, a major hurricane, damaged many U.S. gasoline refineries in 2005, the price of gasoline shot up around the country. The Federal Trade Commission announced that it would investigate price gouging—charging “too much”—and several members of Congress called for price controls on gasoline. What would have been the likely effect of such a law had it been passed? 5.3. Usury laws place a ceiling on interest rates that lenders such as banks can charge borrowers. Why would we expect low-income households in states with usury laws to have significantly lower levels of consumer credit (loans) than comparable households in states without usury laws? (Hint: The interest rate is the price of a loan, and the amount of the loan is the quantity measure.) 5.4. Some cities impose rent control laws, which are price controls or limits on the price of rental accommodations (apartments, houses, and mobile homes). As of 2011, New York City alone had approximately one million apartments under rent control. Show the effect of a rent control law on the equilibrium rental price and the quantity of New York City apartments. Show the amount of excess demand on your supply-and-demand diagram. 5.5. If the minimum wage raises the market wage, w, but hours worked, L, fall as a result, total wage payments, wL, may rise or fall. Use supply and demand curves to show that either outcome is possible depending on the shapes (slopes) of the supply and demand curves. (Hint: With the wage on the vertical axis and hours worked, L, on the horizontal axis, wage payments equal the area of the box with a height of the equilibrium wage and length of the equilibrium hours worked.) 5.6. Use the demand function and the supply function for the avocado market to determine how the equilibrium price and quantity change when a 55¢ per lb specific tax is imposed on this market, as illustrated in Figure 2.9. 5.7. Worried about excessive drinking among young people, the British government increased the tax on beer by 42% from 2008 to 2012. Does a specific tax substantially reduce the equilibrium quantity of alcohol? Answer in terms of the slopes of the demand and supply curves. 5.8. If the government collects a $1 specific tax, what share of the tax is paid by consumers and firms in each of the following cases? Explain why. (Hint: See Q&A 2.3. Depending on the shape of the curves, it may be easier to assume that the tax is collected from consumers or from firms.) a. The demand curve is vertical at quantity Q and the supply curve is upward sloping. b. The demand curve is horizontal at price p and the supply curve is upward sloping. Questions c. The demand curve is downward sloping and the supply curve is horizontal at price p. 5.9. Quebec, Canada, offers a per-child subsidy on day care for young children that lowers the price to $7 per child as of 2011 (at a cost of about $10,000 per child per year). (Hint: A subsidy is a negative tax.) a. What is the effect of this subsidy on the equilibrium price and quantity? b. Show the incidence of the subsidy on day care providers and parents using a supply-anddemand diagram. 6. When to Use the Supply-and-Demand Model 6.1. List as many industries as you can for which the supply-and-demand model is likely to be appropriate. 7. Managerial Problem 7.1. During the spring and summer of 2008 when gasoline prices were rising quickly, politicians in several countries proposed a moratorium on some or all gasoline taxes to help consumers. In the United States, John McCain, the Republican candidate for president, proposed suspending the federal gasoline tax of 18.4¢ for the summer when demand tends to be high. (Hillary Clinton, while an active candidate for the Democratic nomination for the president, also pushed this plan.) In the United Kingdom, Prime Minister Gordon Brown proposed delaying a two pence per liter rise in a fuel tax until the fall. How would these short-run policies have affected the prices consumers pay in these countries if the policies had been enacted? 8. Spreadsheet Exercises12 8.1. Suppose that the market for video games is competitive with demand function Qd = 130 - 4p + 2Y + 3pm - 2pc, where Qd is the quantity demanded, p is the market price, Y is the monthly budget that an average consumer has available for entertainment, pm is the average price of a movie, and pc is the price of a controller that is required to play these games. 41 a. Given that Y = $100, pm = $30, and pc = $30, use Excel to calculate quantity demanded for p = $10 to p = $80 in $5 increments. Use Excel’s charting tool to draw the demand curve. b. Now, Y increases to $120. Recalculate the demand schedule in part a. Use Excel’s charting tool to draw the new demand curve in the same diagram. c. Let Y = $100 and pc = $30 again, but let pm increase to $40. Recalculate the demand schedule in part a. Use Excel’s charting tool to draw the graph of the new demand curve. d. Let Y = $100, pm = $30, and pc increases to $40. Recalculate the demand schedule in part a and use Excel to draw the new demand curve. 8.2. In Smalltown, Pennsylvania, the demand function for men’s haircuts is Qd = 500 - 30p + 0.08Y, where Qd is quantity demanded per month, p the price of a haircut, and Y the average monthly income in the town. The supply function for men’s haircuts is Qs = 100 + 20p - 20w, where Qs is the quantity supplied and w the average hourly wage of barbers. a. If Y = $5000 and w = $10, use Excel to calculate quantity demanded and quantity supplied for p = $5, 10, 15, 20, 25, and 30. Calculate excess demand for each price. (Note that an excess supply is negative excess demand). Determine the equilibrium price and quantity. Use Excel’s charting tool to draw the demand and supply curves. b. Assume that Y increases to $6,875 and w increases to $15. Use Excel to recalculate quantity demanded, quantity supplied, and excess demand for p = $5, 10, 15, 20, 25, and 30. Determine the new equilibrium price and quantity. Use Excel to draw the new demand and supply curves. How can you explain the change in equilibrium? 12The spreadsheet exercises, which appear at the end of each chapter from Chapter 2 on, are based on the work of Satyajit Ghosh in cooperation with the authors. The answers are available on MyEconLab. 3 Ma nagerial P ro blem Estimating the Effect of an iTunes Price Change Empirical Methods for Demand Analysis 98% of all statistics are made up. From the time Apple launched iTunes in mid-2003 through early 2009, it charged 99¢ for each song on its U.S. site. Despite having sold over nine billion songs by early 2009, Apple was under pressure from many sides to change the price. Music producers wanted Apple to charge more. In the United Kingdom, Amazon.com, iTunes’s chief rival, announced that it was launching a price war for MP3 music downloads. Should iTunes raise or lower its price? In April 2009, Apple changed to a new U.S. pricing scheme: 69¢ a song for the older catalog, 99¢ for most new songs, and $1.29 for the most popular tracks. Before the managers of iTunes changed the price, they wanted to predict the likely effect of the price change. Because Apple had always charged a single price, the managers could not use experience with past price variations to estimate the likely consumer response to a price hike. Rather than run a potentially costly experiment of trying different possible prices to see how the quantity demanded would change, iTunes managers could ask a focus group consisting of a random sample of music buyers how they would react to a price hike. After collecting their responses, the managers could analyze the data to predict the likely effects of a price change. How could the managers use the data to estimate the demand curve facing iTunes? How could the managers determine if a price increase would be likely to raise revenue, even though the quantity demanded would fall? M anagers commonly use data to estimate economic relationships, such as the relationship between price and quantity shown by a demand curve, or to examine whether a particular economic theory applies in their markets. Data-based analysis of economic relationships is often referred to as empirical analysis. This chapter discusses empirical methods that can be used to analyze economic relationships, focusing particularly on the empirical analysis of demand. In Chapter 2, we focused on market demand curves in highly competitive markets, such as most agricultural markets. In highly competitive markets with many firms selling identical products, each individual firm is a price taker. In such markets, no one firm can significantly influence the market price. Any firm that tried to raise 42 3.1 Elasticity 43 its price above the market equilibrium price would lose all of its sales. However, many firms, such as Apple, operate in markets that are not as competitive. Such firms are price setters that can raise their prices without losing all their sales. In the market for music downloads, Apple is a price setter. A price-setting firm is concerned about the demand curve facing the firm rather than a market demand curve. In particular, the manager of a price-setting firm often wants to know how responsive its quantity demanded is to changes in its price or in other variables that affect demand. For example, in deciding whether to raise the price of iTunes songs by 30¢, an Apple manager would want to know how the number of iTunes downloads would fall in response to a 30¢ increase in price. This responsiveness can be measured empirically using the price elasticity of demand. A manager might also wish to estimate the entire demand function to decide how to set the firm’s optimal price, plan an advertising campaign, or choose how large a plant to build. In Chapter 2, we used estimated demand (and supply) functions to determine the equilibrium price and to analyze the effects of government policies on the market. This chapter describes how to estimate demand functions using regression analysis, which is an empirical method used to estimate a mathematical relationship between a dependent variable, such as quantity demanded, and explanatory variables, such as price and income. Further, managers often wish to use data to forecast the future value of an important economic quantity such as future sales. This chapter describes major forecasting methods, focusing particularly on the role of regression analysis in forecasting. M a in Topics 1. Elasticity: An elasticity measures the responsiveness of one variable, such as quantity demanded, to a change in another variable, such as price. In this chapter, we examine five main topics 2. Regression Analysis: Regression analysis is a method used to estimate a mathematical relationship between a dependent variable, such as quantity demanded, and explanatory variables, such as price and income. 3. Properties and Statistical Significance of Estimated Coefficients: A regression analysis provides information that can be used to assess how much confidence can be placed in the coefficients of an estimated regression relationship, allowing us to infer whether one variable has a meaningful influence on another. 4. Regression Specification: For a regression analysis to be reliable, the specification— the number and identity of explanatory variables and the functional form of the mathematical relationship (such as linear or quadratic)—must be chosen appropriately. 5. Forecasting: Future values of important variables such as sales or revenues can be predicted using regression analysis. 3.1 Elasticity Managers commonly summarize the responsiveness of one variable—such as the quantity demanded—to a change in another—such as price—using a measure called an elasticity, which is the percentage change in one variable divided by the associated percentage change in the other variable. In particular, a manager can use the elasticity of demand to determine how the quantity demanded varies with price. 44 CHAPTER 3 Empirical Methods for Demand Analysis The Price Elasticity of Demand In making critical decisions about pricing, a manager needs to know how a change in price affects the quantity sold. The price elasticity of demand (or simply the elasticity of demand or the demand elasticity) is the percentage change in quantity demanded, Q, divided by the percentage change in price, p. That is, the price elasticity of demand (which we represent by ε, the Greek letter epsilon) is ε = percentage change in quantity demanded percentage change in price = ΔQ/Q . Δp/p (3.1) The symbol Δ (the Greek letter delta) indicates a change, so ΔQ is the change in the quantity demanded; ΔQ/Q is the percentage change in the quantity demanded; Δp is the change in price; and Δp/p is the percentage change in price. According to Equation 3.1, if a 1% increase in the price of a product results in a 3% decrease in the quantity demanded of that product, the elasticity of demand is ε = -3%/1% = -3. The elasticity of demand is a pure number: it is not measured in any particular units like dollars or pounds (lbs.). A useful way to think about elasticity is to consider the effect of a 1% change. If the price elasticity of demand is –2, a 1% decrease in price would cause quantity demanded to increase by 2%. Arc Elasticity. Very often, a manager has observed the quantity demanded at two different prices. The manager can use this information to calculate an arc price elasticity of demand, which is a price elasticity of demand calculated using two distinct pricequantity pairs. Suppose the manager observes that the quantity of avocados demanded was 76 million pounds per month at a price of $2.10 per pound, but rose to 84 million pounds when the price fell to $1.90. To use Equation 3.1, the manager needs to determine the percentage change in quantity, ΔQ/Q, and the percentage change in price, Δp/p. The change in the quantity demanded as the price falls is ΔQ = 84 - 76 = 8 million pounds. To determine the percentage change in quantity, we need to divide this change by a quantity, Q. Do we use the initial quantity, 76, the final quantity, 84, or something else? When calculating a percentage change, this choice of the base quantity makes a difference. If we use the initial quantity as the base, then the percentage change in quantity is 8/76 ≈ 10.5% (where ≈ means “approximately equal to”). If we use the final quantity as the base, the percentage change is 8/84 ≈ 9.5%. Another approach is to use the average quantity as the base. The average quantity is (76 + 84)/2 = 80, so the associated percentage change is 8/80 = 10%. Many analysts use the average quantity because the elasticity is the same regardless of whether we start at a quantity of 76 and move to 84 or start at 84 and move to 76. If, instead, the manager consistently uses the initial quantity as the base, or consistently uses the final quantity as the base, then the percentage change would vary depending on the direction of movement. The percentage change in price can also be calculated by using the average price as the base. The price change is $1.90 - $2.10 = -$0.20. The average price is ($1.90 + $2.10)/2 = $2.00. Thus, the percentage change in price is -$0.20/$2.00 = -10%. The elasticity is the percentage change in quantity divided by the percentage change in price or 10%/(-10%) = -1. 3.1 Elasticity 45 An arc price elasticity is an elasticity that uses the average price and average quantity as the denominator for percentage calculations. Using Equation 3.1, this arc price elasticity is ε = percentage change in quantity demanded percentage change in price = ΔQ/Q , Δp/p (3.2) where the bars over Q and p indicate average values. Ma nagerial I mplication Changing Prices to Calculate an Arc Elasticity Q& A 3.1 One of the easiest and most straightforward ways for a manager to determine the elasticity of demand for a firm’s product is to conduct an experiment. If the firm is a price setter and can vary the price of its product—as Apple, Toyota, Kraft Foods, and many other firms can—the manager can change the price and observe how the quantity sold varies. Armed with two observations—the quantity sold at the original price and the quantity sold at the new price—the manager can calculate an arc elasticity. Depending on the size of the calculated elasticity, the manager may continue to sell at the new price or revert back to the original price. It is often possible to obtain very useful information from an experiment in a few or even just one small submarket—in one country, in one city, or even in one supermarket. Managers of price-setting firms should consider using such experiments to assess the effect of price changes on quantity sold. In the first week after Apple’s iTunes raised its price on its most popular songs from 99¢ to $1.29, the quantity demanded of Akon’s “Beautiful” fell approximately 9.4% to 52,760 units from the 57,941 units sold in the previous week.1 What is the arc elasticity of demand for “Beautiful” based on the average price and quantity? Answer Use Equation 3.2 to calculate the arc elasticity. The change in the price is Δp = $0.30 = $1.29 - $0.99, and the change in quantity is ΔQ = -5,181 = 57,941 - 52,760. The average price is p = $1.14 = ($0.99 + $1.29)/2, and the average quantity is Q = 55,350.5 = (52,760 + 57,941)/2. Plugging these values into Equation 3.2, we find that the arc price elasticity of demand for this song is ε = ΔQ/Q -5,181/55,350.5 0.094 = ≈ ≈ -0.36. Δp/p 0.30/1.14 0.263 When price rose by 26.3%, the quantity demanded fell by 9.4%, so the arc elasticity of demand was ε = -0.36. Based on this elasticity, a 1% rise in price would cause the quantity demanded to fall by roughly one-third of a percent. Point Elasticity. An arc elasticity is based on a discrete change between two distinct price-quantity combinations on a demand curve. If we let the distance between these two points become infinitesimally small, we are effectively evaluating the elasticity at a single point. We call an elasticity evaluated at a specific price-quantity combination a point elasticity. 1Glenn Peoples, “iTunes Price Change: Sales Down, Revenue Up in Week 1,” Billboard, April 15, 2009. 46 CHAPTER 3 Empirical Methods for Demand Analysis If a manager knows only two specific price-quantity points on a demand curve, then the manager’s best summary of how quantity demanded responds to price changes is the arc elasticity of demand for the movement between these two points. If, on the other hand, the manager has information about the entire demand curve, it is possible to calculate the point elasticity of demand at any point on the demand curve. The point elasticity indicates the effect on the quantity demanded arising from a very small change in price. To calculate a point elasticity, we first rewrite the price elasticity formula, Equation 3.1, as ε = ΔQ/Q ΔQ p = Δp/p Δp Q (3.3) where we are evaluating the elasticity at the point (Q, p) and ΔQ/Δp is the ratio of the change in quantity to the change in price. Holding other variables that affect demand fixed, we can use Equation 3.3 to calculate the elasticity of demand for a general linear demand curve. The mathematical form of a linear demand curve is given by Q = a + bp (3.4) where a and b are parameters or coefficients. We assume that a is a positive constant and b is a negative constant. The parameter a is the quantity that is demanded if the price is zero. The parameter b shows how much the quantity demanded falls if the price is increased by one unit (such as a dollar). As we showed in Chapter 2, if the price changes from p1 to p2, then ΔQ = Q2 - Q1 = (a + bp2) - (a + bp1) = b(p2 - p1) = bΔp, (3.5) so if Δp = 1, the change in the quantity demanded, ΔQ = b, is negative. Rearranging Equation 3.5, we see that ΔQ/Δp = b. Thus, the elasticity of demand for a linear demand curve is ε = p ΔQ p = b . Δp Q Q (3.6) As we discussed in Chapter 2, our estimated linear demand curve for avocados is Q = 160 - 40p, where Q is the quantity of avocados in millions of pounds and p is the price in dollars per pound. For this specific linear demand equation, a = 160 and b = -40. Substituting these values into Equation 3.6, we find that the point elasticity of demand for avocados is p ε = -40 . (3.7) Q Equation 3.7 allows us to determine the elasticity of demand at any point (any price-quantity combination) on the demand curve. In particular, we can find the point elasticity of demand at p = $2.40, where the quantity demanded is Q = 160 - (40 * 2.40) = 64, by substituting these values into Equation 3.7: ε = b p Q = -40 2.40 = -1.5. 64 3.1 Elasticity 47 We previously used the estimated demand function for avocados to calculate the arc elasticity of demand for a price change from $1.90 to $2.10. That elasticity was -1, which is different from the point elasticity of -1.5 just calculated. Although these two elasticities are different, neither is incorrect. Both are appropriate measures— they are just measuring different elasticities. The arc elasticity correctly measures the elasticity associated with a discrete change from a price of $1.90 to a price of $2.10, while the point elasticity correctly measures the elasticity at a price of $2.40. Both elasticity measures are useful. To keep our discussion as short and clear as possible, the subsequent analysis will deal just with point elasticities unless explicitly stated otherwise. Using Calculus The Point Elasticity of Demand Q&A 3.2 As the change in price becomes very small, Δp S 0, the ratio ΔQ/Δp converges to the derivative dQ/dp. Thus, the point elasticity of demand in Equation 3.3 may be written as ε = dQ p . dp Q (3.8) Use calculus to show that the elasticity of demand is a constant ε at all prices if the demand function is exponential, Q = Apε . Given that the estimated demand function for broadband service for large firms is Q = 16p–0.296 (based on Duffy-Deno, 2003), what is the (constant) elasticity of demand? Answer 1. Differentiate the demand function with respect to price to determine dQ/dp, and substitute that expression into the definition of the elasticity of demand. Differentiating the demand function Q = Apε, we find that dQ/dp = εApε - 1. Substituting that expression into the point elasticity definition, Equation 3.8, we learn that the elasticity is p p dQ p = εApε - 1 = εApε - 1 ε = ε. dp Q Q Ap Because the elasticity is a constant that does not depend on a particular value of p or Q, it is the same at every point along the demand curve. 2. Use the rule just derived to determine the demand elasticity for broadband service—the elasticity is the exponent on price in the demand formula. The elasticity of demand, ε, for broadband services for large firms is –0.296 (the exponent on the price in the demand equation). Elasticity Along the Demand Curve Whether the elasticity of demand is the same at every price along the demand curve or varies depends on the shape of the demand curve. The only type of demand curve where the elasticity of demand is the same at every price has the functional form Q = Apε, which is called the constant-elasticity demand form. Along 48 CHAPTER 3 Empirical Methods for Demand Analysis a constant-elasticity demand curve, the elasticity of demand is the same at every price and is equal to the exponent ε, as Q&A 3.2 demonstrates. The constant A for a constant-elasticity demand curve varies with the type of units used to measure the quantity demanded. For example, A is 2,000 times bigger if quantity demanded is measured in pounds rather than in tons, because there are 2,000 pounds in a ton. We now turn to three types of linear demand curves: horizontal demand curves, vertical demand curves, and downward-sloping demand curves, which are neither horizontal nor vertical. Except for constant-elasticity demand curves, the elasticity of demand varies with price along downward-sloping demand curves. In particular, the elasticity of demand is different at every point along a downward-sloping linear demand curve. Horizontal and vertical demand curves are linear, but they have the same price elasticity at every point. Horizontal and vertical demand curves are therefore also special cases of the constant-elasticity demand curve. If the demand curve is horizontal, ε = - ∞ at every point; if the demand curve is vertical, ε = 0 at every point. Downward-Sloping Linear Demand Curves. We can show that the elasticity of demand is different at every point along a downward-sloping linear demand curve. According to Equation 3.6, the elasticity of demand on a linear demand curve is ε = b(p/Q). Although b is a constant, the price-quantity ratio, p/Q, varies as we move along the demand curve, so the elasticity must also vary. The elasticity of demand is a more negative number the higher the price and hence the smaller the quantity. A 1% increase in price causes a larger percentage fall in quantity near the top (left) of the demand curve than near the bottom (right). We use the linear avocado demand curve in Figure 3.1 to illustrate how the elasticity varies with price. At the lower right corner of Figure 3.1, where the avocado demand curve hits the quantity axis ( p = 0 and Q = 160), the elasticity of demand for avocados, Equation 3.7, is ε = -40(p/Q) = -40(0/160) = 0. Where the price is zero, a 1% increase in price does not raise the price—if zero changes by 1% it is still zero. As price does not change, quantity does not change either. At a point where the elasticity of demand is zero, the demand curve is said to be perfectly inelastic. With a linear demand curve, such as the avocado demand curve, the higher the price, the more elastic the demand curve (ε is larger in absolute value: it becomes a more negative number as we move up the demand curve). The demand curve is perfectly inelastic (ε = 0) where the demand curve hits the horizontal axis, is perfectly elastic where the demand curve hits the vertical axis, and has unitary elasticity at the midpoint of the demand curve. p, $ per lb F IG U RE 3. 1 The Elasticity of Demand Varies Along the Linear Avocado Demand Curve 4 Perfectly elastic Elastic: ε < –1 3 ε = –3 D 2 Unitary: ε = –1 Inelastic: 0 > ε > –1 1 0 ε = –1/3 40 80 Perfectly inelastic 120 160 Q, Million lbs of avocados per month 3.1 Elasticity 49 For quantities between the midpoint of the linear demand curve and the lower end where p = 0, the demand elasticity lies between zero and negative one: 0 7 ε 7 -1. A point along the demand curve where the elasticity is between 0 and -1 is inelastic (but not perfectly inelastic): A 1% increase in price leads to a fall in quantity of less than 1%. For example, when the avocado price is $1 so that the quantity demandedis 120, the elasticity of demand is ε = -40(1/120) = - 13, so a 1% increase in price causes quantity to fall by a third. Rearranging the elasticity formula in Equation 3.1, the percentage change in Q is ε times the percentage change in price: ΔQ/Q = ε(Δp/p). If the elasticity ε lies between 0 and -1, the percentage change in quantity is smaller than the percentage change in price. Thus, demand is inelastic in the sense that it changes little in response to a price change. As a physical analogy, if you try to stretch a rope, it stretches only slightly. The change in the price is the force pulling at demand, just as your effort provides the force pulling at the rope. If the quantity demanded does not change much in response to this force, the demand curve is called inelastic. At the midpoint of the linear demand curve, a 1% increase in price causes a 1% fall in quantity, so the elasticity equals –1, which is called unitary elasticity.2 At prices higher than at the midpoint of the demand curve ($2 on the avocado demand curve), the elasticity of demand is less than negative one, ε 6 -1. That is, the elasticity is a more negative number because it is larger in absolute value. In this range, the demand curve is called elastic. A physical analogy is a rubber band that stretches substantially when you pull on it. A 1% increase in price causes a more than 1% fall in quantity. Figure 3.1 shows that the avocado demand elasticity is –3 where the price is $3 and 40 million lbs are demanded: a 1% increase in price causes a 3% drop in quantity. Where the demand curve hits the price axis at p = $4 and Q = 0, the elasticity of demand is ε = -b(4/0). As Q approaches zero, the elasticity becomes a larger and larger negative number that approaches negative infinity, - ∞. The demand curve is perfectly elastic at the point where Q = 0. Because quantity is zero at p = 4, if we lower the price even slightly so that the quantity demanded becomes positive, there is an infinite percentage increase in the quantity demanded. Horizontal Demand Curves. Horizontal demand curves have constant elasticity (as do vertical demand curves). The demand curve that is horizontal at p* in panel a of Figure 3.2 shows that people are willing to buy as much as firms want to sell at any price less than or equal to p*. If the price increases even slightly above p*, however, demand falls to zero. Thus, a small increase in price causes an infinite drop in quantity, so the demand curve is perfectly elastic.3 A horizontal demand curve is an extreme case of a linear demand curve: it is the flattest possible linear demand curve. Unlike downward-sloping linear demand curves, a horizontal demand curve does not have the property that the elasticity = a/2 and p = -a/(2b), so, using Equation 3.6, ε = bp/Q = -b(a/[2b])/(a/2) = -1. 3Using the constant-elasticity demand function, as ε becomes a very large negative number, the demand curve becomes increasingly flat and approaches a horizontal line. 2At the midpoint of a general linear demand curve, Q 50 CHAPTER 3 Empirical Methods for Demand Analysis F IG U RE 3. 2 Vertical and Horizontal Demand Curves (a) Perfectly Elastic Demand (b) Perfectly Inelastic Demand (c) Individual’s Demand for Insulin p, Price per unit p, Price of insulin dose who is diabetic is perfectly inelastic below p* and perfectly elastic at p*, which is the maximum price the individual can afford to pay. p, Price per unit (a) A horizontal demand curve is perfectly elastic at p*. (b) A vertical demand curve is perfectly inelastic at every price. (c) The demand curve for insulin of an individual p* Q, Units per time period Q* Q, Units per time period p* Q * Q, Insulin doses per day changes along the demand curve. For a horizontal demand curve, the elasticity is negative infinity at every point. Why would a good’s demand curve be horizontal? One reason is that consumers view this good as identical to another good and do not care which one they buy. If consumers view Delicious apples grown in Washington and Delicious apples grown in Oregon as identical, they won’t buy Washington apples if these sell for more than apples from Oregon. Similarly, they won’t buy Oregon apples if their price is higher than that of Washington apples. If the two prices are equal, consumers do not care which type of Delicious apple they buy. Thus, the demand curve for Oregon apples is horizontal at the price of Washington apples. Vertical Demand Curves. A vertical demand curve, as in panel b in Figure 3.2, is perfectly inelastic everywhere. Such a demand curve is an extreme case of a linear demand curve—the opposite extreme from the horizontal demand curve. A vertical demand curve has an infinite (vertical) slope. A vertical demand function is also a special case of the constant-elasticity demand function. If ε takes on the value 0, then the demand function is Q = Ap0 = A, so the demand curve is a vertical line at quantity A. If the price goes up, the quantity demanded is unchanged, so ΔQ = 0. The elasticity of demand as given by Equation 3.1 must be zero: (ΔQ/Δp)(p/Q) = (0/Δp)(p/Q) = 0. A demand curve is vertical for essential goods—goods that people feel they must have and will pay anything to get. Because Jerry has diabetes, his demand curve for insulin could be vertical at a day’s dose, Q*. Panel c of Figure 3.2 assumes that there is a maximum feasible price of p* and illustrates that demand is unchanged at Q* for all possible prices less than p*. Other Demand Elasticities In addition to the price elasticity of demand, we can also use elasticities to summarize how quantity demanded changes in response to changes in variables other than the good’s price. Two such elasticities are the income elasticity of demand and the cross-price elasticity of demand. 3.1 Elasticity 51 The income elasticity of demand is the percentage change in the quantity demanded divided by the percentage change in income, Y: percentage change in quantity demanded percentage change in income = ΔQ/Q ΔQ Y . = ΔY/Y ΔY Q We say a good is normal if the quantity demanded increases as income rises. That is, a normal good has a positive income elasticity of demand. Goods like avocados or music downloads are normal goods: people buy more of them when their incomes rise. Conversely, a good is inferior if the quantity demanded falls as income rises. Inferior goods have negative income elasticities. For many college students, Kraft Macaroni & Cheese (food in a box) is an inferior good—they buy it when their incomes are low but switch to more appealing and expensive foods when their incomes rise. The cross-price elasticity of demand is the percentage change in the quantity demanded divided by the percentage change in the price of another good, po: percentage change in quantity demanded percentage change in other price = ΔQ po . ΔQ/Q = Δpo/po Δpo Q When the cross-price elasticity is negative, people buy less of the good if the price of the other good rises. Such goods are called complements. For example, if people insist on having cream in their coffee then, as the price of cream rises, they consume less coffee. The cross-price elasticity of coffee demanded with respect to the price of cream is negative. If, alternatively, the cross-price elasticity is positive, the goods are called substitutes. As the price of one good rises, people buy more of the substitute good. For example, as avocados and tomatoes are substitutes, the quantity of avocados demanded increases if the price of tomatoes rises (Chapter 2). Mini-Case Substitution May Save Endangered Species One reason that many species—including tigers, rhinoceroses, green turtles, geckos, sea horses, pipefish, and sea cucumbers—are endangered, threatened, or vulnerable to extinction is that certain of their body parts are used as aphrodisiacs in traditional Chinese medicine. Is it possible that consumers will switch from such potions to Viagra, a less expensive and almost certainly more effective alternative treatment, and thereby help save these endangered species? We cannot directly calculate the cross-price elasticity of demand between Viagra and the price of body parts of endangered species because their trade is illicit and not reported. However, harp seal and hooded seal genitalia, which are used as aphrodisiacs in Asia, may be legally traded. Before 1998, Viagra was unavailable (effectively, it had an infinite price—one could not pay a high enough price to obtain it). When it became available in Canada at about C$15 to C$20 per pill, the demand for seal sex organs fell and the demand curve shifted substantially to the left. According to von Hippel and von Hippel (2002, 2004), 30,000 to 50,000 seal organs were sold in the years just before 1998. In 1998, only 20,000 organs were sold. By 1999–2000 (and thereafter), virtually none were sold. A survey of older Chinese males confirms that, after the introduction of Viagra, they were much more likely to use a Western medicine than traditional Chinese medicines for erectile dysfunction, but not for other medical problems (von Hippel et al., 2005). 52 CHAPTER 3 Empirical Methods for Demand Analysis This evidence suggests a strong willingness to substitute Viagra for seal organs at current prices and, thus, that the cross-price elasticity between the price of seal organs and Viagra is positive. Thus, Viagra can perhaps save more than marriages. Demand Elasticities over Time The shape of a demand curve depends on the time period under consideration. Often one can substitute between products in the long run but not in the short run. When gasoline prices nearly doubled in 2008, most Western consumers did not greatly alter the amount of gasoline that they demanded in the short run. Someone who drove 27 miles to and from work every day in a recently purchased Ford Explorer could not easily reduce the amount of gasoline purchased. However, in the long run, this person could buy a smaller vehicle, get a job closer to home, join a car pool, or reduce the amount of gasoline purchased in other ways. A survey of hundreds of estimates of gasoline demand elasticities across many countries (Espey, 1998) found that the average estimate of the short-run elasticity was –0.26, and the long-run elasticity was –0.58. Thus, a 1% increase in price lowers the quantity demanded by only 0.26% in the short run but by more than twice as much, 0.58%, in the long run. Bento et al. (2009) estimated a long-run U.S. elasticity of only –0.35. Apparently, U.S. gasoline demand is less elastic than in Canada (Nicol, 2003) and a number of other countries. Other Elasticities The relationship between any two related variables can be summarized by an elasticity. In addition to the various demand elasticities that we’ve mentioned, other elasticities are also important. For example, just as we might measure the price elasticity of demand, we might also measure the price elasticity of supply—which indicates the percentage increase in quantity supplied arising from a 1% increase in price. A manager might be very interested in the elasticity of cost with respect to output, which shows the percentage increase in cost arising from a 1% increase in output. Or, during labor negotiations, a manager might cite the elasticity of output with respect to labor, which would show the percentage increase in output arising from a 1% increase in labor input, holding other inputs constant. Estimating Demand Elasticities Price, income, and cross-price demand elasticities are important managerial tools. Managers can use them to predict how the quantity demanded will respond to changes in consumer income, the product’s own price, or the price of a related good. Managers use this information to set prices, as in the iTunes example, and in many other ways. Managers use data to calculate or estimate elasticities. For example, Q&A 3.1 shows how a manager can observe the quantity effect of a change in price to determine the elasticity of demand for iTunes downloads of Akon’s “Beautiful.” Such a before-andafter price change calculation uses data from before the price change and after the price change to calculate an arc elasticity. By comparing quantities just before and just after a price change, managers can be reasonably sure that other variables that might affect the quantity demanded, such as income, have not changed appreciably. 3.2 Regression Analysis 53 Managers at iTunes could do such calculations for many songs and obtain an estimate of how the iTunes price change affected overall sales. Such information could then be used for further decision making within iTunes—such as decisions about how quickly to expand and upgrade server capacity or about whether to charge different prices for various songs. However, it may not always be feasible or desirable for a manager to calculate a before-and-after arc elasticity. A manager often wants an estimate of the demand elasticity before actually making a price change, so as to avoid a potentially expensive mistake. Similarly, a manager may fear a reaction by a rival firm in response to a pricing experiment. Also, a manager wants to know the effect on demand of many possible price changes rather than focusing on just one price change. The manager can use such information to select the best possible price rather than just choose between two particular prices. In effect, the manager would like an estimate of the entire demand curve. Regression analysis is an empirical technique that can be used to estimate an entire demand curve in addition to estimating other important economic relationships. Mini-Case Turning Off the Faucet 3.2 During droughts, consumers demand more water than the local water utility can supply. The managers of the water utility have to reduce consumption, which they usually do by imposing quotas on consumers. But, should managers consider the alternative of raising the price to reduce consumption? Is that approach feasible, or will households pay “virtually anything” for water? Many water utility managers and political leaders think that water usage is nearly perfectly inelastic (not sensitive to price). When water is plentiful, public water utilities typically supply water at a price below the cost of providing an extra unit of water to help the poor (and others), figuring that it doesn’t greatly affect usage. Nataraj (2007) used a natural experiment to determine the sensitivity of the quantity of water demanded to price. Like many cities, Santa Cruz, California, sells water using increasing block pricing. Initially, the city charged 65¢ per unit (100 cubic feet) for the first 8 units of water and $1.55 for each extra unit. However, after a drought, it raised its rates and added a third block, charging 69¢ per unit for the first 8 units, $1.64 per unit for units 9–39, and $3.14 per unit for 40 or more units. Nataraj concluded that the nearly 100% increase in price for 40 or more units led to a 15% to 25% decrease in consumption among heavy users. This result shows that the demand for water is inelastic, but not perfectly inelastic. By substantially raising prices, a government can cut water demand by heavy users significantly, but less than in proportion to the price change. Regression Analysis Regression analysis is a statistical technique used to estimate the mathematical relationship between a dependent variable, such as quantity demanded, and one or more explanatory variables, such as price and income. The dependent variable is the variable whose variation is to be explained. The explanatory variables are the factors that are thought to affect the value of the dependent variable. 54 CHAPTER 3 Empirical Methods for Demand Analysis We focus on using regression analysis to estimate demand functions. However, regression analysis is a powerful tool that is also used to estimate many other relationships of interest to managers. For example, it is possible to estimate the relationships between cost and output or between wages and productivity using regressions. The use of regression analysis and related statistical methods in economics and business is called econometrics. A Demand Function Example To illustrate the use of regression, we estimate a demand function, where the dependent variable is the quantity demanded. In general, a demand function may include a number of explanatory variables. However, we initially focus on the case in which there is only one explanatory variable, the price. We assume that other factors that might affect the quantity demanded, such as income and prices of related goods, remain constant during the relevant period. A demand function with price as the only explanatory variable defines a demand curve. We also assume initially that the demand function curve is linear. That is, the true relationship between the quantity demanded and the price is a straight line, as in Figure 3.1. The Demand Function and the Inverse Demand Function. There are two ways to write the relationship between the quantity demanded and the price. Quantity is a function of price in a demand function, while price is a function of quantity in an inverse demand function. An example of a linear demand function with only one explanatory variable is Equation 3.4: Q = a + bp. We can use algebra to rearrange this linear demand equation so that the price is on the left side and the quantity is on the right side. By subtracting a from both sides to obtain Q - a = bp, dividing both sides of the equation by b to obtain (1/b)Q - a/b = p, and rearranging the terms in the equation, we obtain p = - a 1 + Q = g + hQ, b b (3.9) where g = -a/b 7 0 and h = 1/b 6 0, because b is negative. This equation, with p on the left side, is called the inverse demand function. If a demand function is a linear function of p, as in Equation 3.4, then the inverse demand function, Equation 3.9, is a linear function of Q with constant coefficients g and h. The inverse demand function and the demand function contain exactly the same information. Both versions of the demand relationship yield the same straight line when plotted on a diagram and both versions are commonly used. Indeed, many people ignore the distinction between the inverse and direct forms and use the term demand function (or demand curve) to describe both. However, when doing regression analysis it is necessary to be clear about which version of the demand function we are estimating. In regression analysis, we put the dependent variable on the left side of the equation and the explanatory variable on the right side. For example, Bill, the manager of the only lawn care firm in town, surveys customers about how many lawn treatments they will buy at various prices. He views the price as the explanatory variable and the quantity as the dependent variable, so he uses the survey to estimate a demand curve. If instead his survey asked how 3.2 Regression Analysis 55 much customers were willing to pay for various numbers of lawn treatments, he would estimate the inverse demand equation. Random Errors. For illustrative purposes, we have so far treated the estimated avocado demand curve, Q = 160 - 40p, as if it is precisely correct. The demand curve tells us that if price is $2, then the quantity demanded is 80 (million pounds), and if price falls to $1.80, then quantity demanded must rise to 88. The real world is not that precise. When we look at actual data, we might see that in a month when price was $2, quantity demanded was slightly less than 80, while in a month when price was $1.80 quantity demanded was slightly more than 88. In practical terms, an estimated demand curve is only an estimate; it does not necessarily match actual data perfectly. The imperfection in our estimate arises because we can never hold constant all the possible nonprice factors that affect demand. For example, if New York experiences unusually warm weather in a particular month, New Yorkers might increase their demand for foods used in salads, including avocados. Many other factors, including random changes in consumer tastes, might also play a role. The data may contain errors. For instance, one month someone may have failed to record a large avocado shipment so that it never showed up in the official data. There are many reasons aside from price changes why the data might exhibit month to month changes in quantity demanded. If these other factors that affect demand are observed, such as consumers’ income, we can include these variables as explanatory variables when we estimate our demand function. However, there are many other factors that are not observed or measured and hence that we cannot include explicitly. When we estimate a demand curve using regression analysis, we capture the effect of these unobserved variables by adding a random error term, e, to the demand equation: Q = a + bp + e. (3.10) The random error term captures the effects of unobserved influences on the dependent variable that are not included as explanatory variables. The error is called random because these factors that might affect demand are unpredictable or even unknowable from the manager’s point of view. Regression analysis seeks to estimate the underlying straight line showing the true effect of price on the quantity demanded by estimating a and b in Equation 3.4 while taking account of the random error term. If we could somehow hold e constant at zero, we could obtain various combinations of Q and p and trace out the straight line given by Equation 3.4, Q = a + bp. However, if e does not equal zero, then the observed Q is not on this line. For example, if e takes on a positive value for one month, corresponding to some positive random effect on demand, then the actual Q is larger than the value implied by the linear demand curve Q = a + bp. M ini-Case The Portland Fish Exchange The Portland Fish Exchange of Portland, Maine, can be used to illustrate the application of regression analysis to demand estimation. At the Exchange, fishing boats unload thousands of pounds of cod and many other types of fish on a daily basis. The fish are weighed and put on display in the Exchange’s 22,000-square-foot refrigerated warehouse. Buyers inspect the quality of the day’s catch. At noon, an auction is held in a room overlooking the fish in the warehouse. Fleece-clad buyers representing fish dealers and restaurants sit facing a screen, an auctioneer, and representatives of the sellers. Bid information is posted on the screen at the 56 CHAPTER 3 Empirical Methods for Demand Analysis front of the room. Thousands of pounds of fish are sold rapidly. The quantity of fish delivered each day, Q, varies due to fluctuations in weather and other factors. Because fish spoils rapidly, all the fish must be sold immediately. Therefore, the daily auction price for cod adjusts to induce buyers to demand the amount of cod available on that particular day. Thus, the price-quantity combination for cod on any particular day represents a point on the cod demand curve. For each day it operates, the Portland Fish Exchange reports the quantity (in pounds) of each particular type of fish sold and the price for that type of fish. For example, on June 12, 2011, 5,913 pounds of cod were sold at $1.46 per pound. A collection of such observations provides a data set that can be used for demand analysis using regression. Here, quantity is the explanatory variable. Whatever quantity is brought to market is sold that day. Price adjusts to insure that the amount of fish available is demanded by the buyers. As price is “explained by” the quantity brought to market, we can estimate an inverse demand curve. Regression Analysis Using Microsoft Excel. We illustrate how to estimate a linear regression based on data from the Portland Fish Exchange using Microsoft Excel. Table 3.1 shows a data set (or sample) based on reports published online by the Portland Fish Exchange. Each data point is a pair of numbers: the price (dollars per pound) and the quantity of cod (thousands of pounds) bought on a particular day. Our analysis uses eight daily observations. We have ordered the data from the smallest quantity to the largest to make the table easy to read. Figure 3.3 shows the data points in this sample. Estimating this linear regression is equivalent to drawing a straight line through these data points such that the data points are as close as possible to the line. To fit this line through the quantity-price observations for cod, we estimate the linear inverse demand curve, Equation 3.9, with an error term attached: p = g + hQ + e. (3.11) TABLE 3.1 Data Used to Estimate the Portland Fish Exchange Cod Demand Curve Price, dollars per pound Quantity, thousand pounds per day 1.90 1.5 1.35 2.2 1.25 4.4 1.20 5.9 0.95 6.5 0.85 7.0 0.73 8.8 0.25 10.1 3.2 Regression Analysis 57 Each dot indicates a particular price and the quantity of cod demanded at that price on a particular day at the Portland Fish Exchange. p, $ per pound F IG U RE 3. 3 Observed Price-Quantity Data Points for the Portland Fish Exchange 1.90 1.63 1.35 1.00 0.25 0 2.2 4 6 8 10 Q, Thousand lbs of cod per day The error term, e, captures random fluctuations in factors other than quantity that affect the price on a given day, such as random variations in the number of buyers who show up from day to day.4 We expect that the error term averages zero in large samples.5 In Equation 3.11, g and h are the true coefficients, which describe the actual relationship between price and quantity along the cod inverse demand function. The regression provides us with estimates of these coefficients, gn and hn, which we can use to predict the expected price, pn , for a given quantity: pn = gn + hnQ. (3.12) One way to estimate gn and hn is to use the Microsoft Excel Trendline option for scatterplots.6 1. Enter the quantity data in column A and the price data in column B. 2. Select the data, click on the Insert tab, and select the Scatter option in the Chart area of the Toolbar. A menu of scatterplot types will appear, as the following screenshot shows. 4The cod supply curve each day is vertical at Q and is largely determined by weather and government regulations on fishing. Because the quantity is determined independent of the price, it is said to be exogenous. As a result, we can use quantity to help explain the movement of the dependent variable, price, in our regression equation. Where the supply curve intersects the demand curve determines the equilibrium price for that day. Thus, the fluctuations in the quantity—shifts in the vertical supply curve—trace out the demand curve. The dependent variable, price, is endogenous: it is determined inside the system by quantity and by the unobserved variables incorporated in the error term. If quantity and price are simultaneously determined—that is, both are endogenous variables—the demand curve should be estimated using different techniques than those we discuss here. 5We use a small data set in this and later examples to keep the presentation short and clear. In practice, regression analysis would normally involve many more observations. Although some studies use only 30 or 40 observations, most regression studies would normally involve hundreds or even thousands of observations, depending on the availability of data. 6The following screenshots and detailed instructions are for the Windows version of Excel, but the Macintosh version is similar. Helpful instructions can be found in the Excel Help facility. 58 CHAPTER 3 Empirical Methods for Demand Analysis 3. Select the first scatterplot type, which is “Scatter with markers only.” 4. Select the Layout option under the Chart Tools tab. 5. Click Trendline, then click More Trendline Options if nececessary. The Format Trendline dialog should display, as shown in the following screenshot. In this dialog select the options Linear, Automatic, Display Equation, and Display R-squared value, then click Close. The estimated regression line appears in the diagram. 3.2 Regression Analysis 59 By default, Excel refers to the variable on the vertical axis as y (which is our p) and the variable on the horizontal axis as x (which is our Q). Rounding the coefficient estimates to two decimal places, we obtain the estimated inverse demand curve pn = 1.96 - 0.15Q, (3.13) where gn = 1.96 and hn = -0.15 are the estimated coefficients. The estimated inverse demand curve hits the price axis at gn = 1.96, where the price is high enough to drive the quantity demanded to zero. The estimated coefficient hn = -0.15 is the slope of the inverse demand curve. As the quantity increases by one unit (that is, by 1,000 pounds), the estimated change in price needed to induce buyers to purchase this larger quantity is hn = -$0.15 = -15¢.7 Ordinary Least Squares Regression. How does the regression routine in Excel estimate the parameters gn and hn? The objective of the regression procedure is to select a regression line that fits the data well in the sense that the line is as close as possible to all the observed points. As Figure 3.4 shows, it would be impossible to draw a single straight line that fits the data perfectly by going through all eight points. Figure 3.4 shows that there are differences between the actual prices and the prices predicted by the regression line. The second data point from the left (p = $1.35 and Q = 2.2) has the largest gap between the actual and predicted prices. The predicted price, given by Equation 3.13, for Q = 2.2 is pn = 1.96 - 0.15Q = 1.96 - (0.15 * 2.2) = 1.63. The gap between the actual value of the dependent variable (price) and the predicted value is called a residual. For this observation, the residual is $1.35 - $1.63 = -$0.28, indicating that the actual price is 28¢ below the estimated price. The objective of a regression method is to fit the line to the data such that the residuals are collectively small in some sense. However, there are different criteria that might be used to measure the quality of the fit, leading to different regression methods. The most commonly used regression method is ordinary least squares (OLS). Excel uses this method in its scatterplot Trendline option. The OLS regression method fits the line to minimize the sum of the squared residuals. If ne1 is the residual for the first data point, ne2 is the residual for the second data point, and so on, then OLS minimizes the sum ne21 + ne22 + c + ne28.8 price is pn1 = gn + hnQ when quantity is Q and pn2 = gn + hn(Q + 1) when quantity is Q + 1. Thus, the change in price is p2 - p1 = (gn + hn[Q + 1]) - (gn + hnQ) = hn. Similarly, using calculus, dpn /dQ = hn. 7The we have a regression equation of the form Y = a + bX + e, the formulas used by spreadsheets and statistical programs to determine the OLS parameters are: 8If n bn = a (Xi - X)(Yi - Y) i=1 n , and an = Y - bn X, 2 a (Xi - X) i=1 where the observations are indexed by i, there are n observations, a bar above a variable indicates n the average value of that variable, and the symbol a indicates that the following expression should i=1 be summed from observation 1 through observation n. 60 CHAPTER 3 Empirical Methods for Demand Analysis The dots show the actual quantityprice pair data points. The line is the estimated regression line of the linear relationship between the price and the quantity: pn = gn + hnQ = 1.96 - 0.15Q. The gap between the actual price, p, at a given quantity and the estimated price, pn , is the residual for Day i, en i = pi - pn i. The figure shows the residual for the second day, where Q = 2.2, the observed price is p2 = $1.35, and the estimated price is pn 2 = $1.63, so the residual is en 2 = -$0.28 = $1.35 - $1.63. p, $ per pound F IG U RE 3. 4 An Estimated Demand Curve for Cod at the Portland Fish Exchange 1.90 1.63 e1 Estimated regression line, p = g + hQ e2 1.35 e4 1.00 e7 e8 0.25 0 2.2 6 4 8 10 Q, Thousand lbs of cod per day Multivariate Regression A regression with two or more explanatory variables is called a multivariate regression or multiple regression. In our cod example, if the price consumers are willing to pay for a given quantity increases with income, Y, then we would estimate an inverse demand function that incorporates both quantity and income as explanatory variables as p = g + hQ + iY + e, (3.14) where g, h, and i are coefficients to be estimated, and e is a random error. Using OLS, we would estimate the regression line: pn = gn + hnQ + ni Y, where gn , hn, and ni are the estimated coefficients and pn is the predicted value of p for any given levels of Q and Y. The objective of an OLS multivariate regression is to fit the data so that the sum of squared residuals is as small as possible, where the residual for any data point is the difference between actual price, p, and predicted price, pn . A multivariate regression is able to isolate the effects of each explanatory variable holding the other explanatory variables constant. If we use our estimated avocado demand function from Equation 2.2 and hold the price of tomatoes fixed at the base level of $0.80 per lb, the estimated industry demand function is n = 120 - 40p + 0.01Y, Q where quantity is measured in millions of lbs per month, price is measured in dollars per lb, and Y represents average monthly income in dollars. According to this estimated equation, if average income rises by $200 per month and the price of avocados stays constant, then the estimated quantity would rise by 0.01 * 200 = 2 million lbs per month. The regression equation allows us to estimate the effect of changing only one variable, like income, while holding other explanatory variables constant. 3.2 Regression Analysis 61 Similarly, if income remains constant and the price increases by 5¢ (=$0.05) per lb, then the estimated quantity demanded changes by 40 * 0.05 = 2 million lbs per month. Q& A 3.3 n = 120 - 40p + 0.01Y. Suppose the estimated demand function for avocados is given by Q The manager of a trucking company that specializes in avocado transport wishes to use this estimated demand curve to predict the quantity of avocados demanded at price of $2.70 and an income level of $6,000. What is the predicted quantity? If the actual quantity turns out to be 76 (million lbs) what is the residual? Why would the predicted quantity differ from the actual quantity? Answer Use the estimated demand function to determine the predicted quantity. The n = 120 - 40(2.70) + 0.01(6000)Y = 72. If the actual quanpredicted quantity is Q tity is 76, then the residual is 76 – 72 = 4. The actual quantity differs from the predicted quantity because of the random error reflecting other variables not explicitly included in the regression equation. Goodness of Fit and the R2 Statistic Because an estimated regression line rarely goes through all the data points, managers want some measure of how well the estimated regression line fits the data. One measure of the goodness of fit of the regression line to the data is the R2 (R-squared) statistic. The R2 statistic is the share of the dependent variable’s variation that is “explained by the regression”—that is, accounted for by the explanatory variables in the estimated regression equation. The highest possible value for R2 is 1, which indicates that 100% of the variation in the dependent variable is explained by the regression. Such an outcome occurs if the dependent variable lies on the regression line for every observation. If some observations do not lie on the regression line, as in Figure 3.4, then the R2 is less than 1. The variation in the dependent variable that is not explained by the regression line is due to the error term in the regression. Given that the regression includes a constant term, the lowest possible value for R2 is zero, where the estimated regression explains none of the variation in the dependent variable. The R2 is zero if we try to fit a line through a cloud of points with no obvious slope. Thus, the R2 statistic must lie between 0 and 1. For example, Mai owns bakeries in two different small towns, where she faces no competition. She wants to know how many fewer pies she will sell if she raises her price, so she runs experiments in each town. At each bakery, she sets a new price each week for 14 consecutive weeks, so that she observes 14 weekly price-quantity combinations for each town. She then runs a regression to estimate the weekly demand curve, Q = a + bp, Equation 3.4, in each town, where we expect that a is positive and b is negative. Figure 3.5 illustrates these two regressions based on different data sets. In panel a, all the data points are very close to the estimated demand curve. That is, almost all of the variation in the number of pies demanded is explained by the regression. The R2 statistic is 0.98, which is very close to 1, indicating that the regression line provides very good predictions of the amount demanded at any given price. (As the CHAPTER 3 62 Empirical Methods for Demand Analysis F IG U RE 3. 5 Two Estimated Apple Pie Demand Curves with Different R2 Statistics (a) R 2 = 0.98 (b) R 2 = 0.54 p, $ per pie where R2 = 0.98. In panel b, where R2 = 0.54, the data points are more widely scattered around the estimated demand curve. p, $ per pie Mai, a bakery owner, changes the price of apple pie every Friday for 14 weeks to determine the weekly demand curve for apple pie. The observed price-quantity data points lie close to the estimated demand curve in panel a 15 15 10 10 5 5 0 10 20 30 40 Q, Thousands of pies per month 0 10 20 30 40 Q, Thousands of pies per month Portland cod regression screenshot illustrates, Excel’s Trendline includes an option to calculate the R2.) In contrast, the regression line in panel b does not fit the data as well. There are some very large divergences between data points and the predicted values on the regression line due to large random errors, and the R2 statistic is only 0.54. Thus, Mai is more confident that she can predict the effect of a price change in the first town than in the second. Ma nagerial I mplication Focus Groups A recent survey of North American males found 42% were overweight, 34% were critically obese, and 8% ate the survey. —Banksy Managers interested in estimating market demand curves often can obtain data from published sources, as in our Portland Fish Exchange example. However, if Mai, the baker, wants to estimate the demand function for her firm, she must collect the relevant data herself. To estimate her firm’s demand curve, she needs information about how many units customers would demand at various prices. Mai can hire a specialized marketing firm to recruit and question a focus group, which consists of a number of her actual or potential consumers. Members of the group are asked how many pies per week they would want to buy at various prices. Alternatively, the marketing firm might conduct an online or written survey of potential customers designed to elicit similar information, which can be used to estimate a demand curve. Mai should use a focus group if it’s the least costly method of learning about the demand curve she faces. 3.3 Properties and Statistical Significance of Estimated Coefficients 3.3 63 Properties and Statistical Significance of Estimated Coefficients Mai is particularly concerned about how close the estimated coefficients of the demand Equation 3.4, an and bn, are to the true values. She cares because they determine how reliably she can predict the reduction in the number of pies she sells if she raises her price. We now discuss the properties of these estimated coefficients and describe statistics that indicate the degree of confidence we can place in these estimated coefficients. These statistics can be obtained using most regression software, including the regression tools in Excel. Repeated Samples The intuition underlying statistical measures of confidence and significance is based on repeated samples. For example, Mai could use another focus group to generate an additional sample of data. She could then run a new regression and compare the regression for the first sample to that from this new focus group. If the results from the second sample were similar to those from the first, she would be more confident in the results. If, on the other hand, the results of the second sample were very different from those of the first, she might have significant doubts about whether the estimated demand parameters an and bn from either focus group were close to the true values. Often it is costly, difficult, or impossible to gather repeated samples to assess the reliability of regression estimates. However, we can do something similar—we can divide a large data set into two subsamples and treat each subsample like a separate experiment. We can use each subsample to calculate regression parameter estimates. For that matter, we can take many random subsamples of the data set and generate estimates for each subsample. We can then assess whether the different parameter estimates for the different subsamples tend to be similar or widely dispersed. Although the process of running regressions on random subsets of the data and building up a set of parameter estimates is sometimes used, it may be unnecessary. Given certain (usually reasonable) assumptions, we can use statistical formulas to determine how much we would expect the parameter estimates to vary across samples. The nature of this potential variation allows us to assess how much confidence to place in particular regression results. Desirable Properties for Estimated Coefficients We would like our regression estimation method to have two properties. First, we would like the estimation technique to be unbiased in the sense that the estimated coefficients are not systematically lower or systematically higher than the true coefficients. An estimation method is unbiased if it produces an estimated coefficient, bn, that equals the true coefficient, b, on average. The ordinary least squares regression method is unbiased under mild conditions.9 9One important condition for OLS estimation to be unbiased is that the equation be properly speci- fied so that all relevant explanatory variables are included and the functional form is appropriate. 64 CHAPTER 3 Empirical Methods for Demand Analysis The second property we would like an estimation technique to have is that the estimates should not vary greatly if we repeat the analysis many times using other samples. If we have two proposed unbiased estimation methods, we prefer the method that yields estimates that are consistently closer to the true values rather than a method that produces widely dispersed estimates in repeated samples. An important theoretical result in statistics is that under a wide range of conditions, the ordinary least squares estimation method produces estimates that vary less than other relevant unbiased estimation methods. For each estimated coefficient, the regression program calculates a standard error. The standard error is a measure of how much each estimated coefficient would vary if we reestimated the same underlying true demand relation with many different random samples of observations. The smaller the standard error of an estimated coefficient, the smaller the expected variation in the estimates obtained from different samples. A small standard error means that the various estimated coefficients would be tightly bunched around the true coefficient. If the standard error is large, the estimated coefficients are imprecise indicators of the true values. A Focus Group Example Consumers are statistics. Customers are people. —Stanley Marcus (early president of Neiman Marcus) To illustrate these ideas, suppose that Toyota has asked us to conduct a focus group to predict how the number of Toyota Camry vehicles demanded would change if the price changes. We arrange a focus group of 50 prospective car buyers to illustrate how Toyota could answer this question. We ask members of the group if they would be willing to buy a Camry at various prices. As a result, for each of eight prices ranging from $5,000 to $40,000, we have information on how many Camry vehicles would be demanded by this group. We estimate a linear demand curve of the form Q = a + bp + e and obtain standard errors to assess the reliability of the estimated parameters. The Excel Trendline does not provide standard errors. However, they are provided by another tool available in Excel for running regressions, the LINEST (for line estimate) function.10 To use this tool: 1. Enter the data in an Excel spreadsheet as in the following screenshot on the left, putting the quantity in Column A and the price (in thousands of dollars) in Column B. 2. As the left screenshot shows, enter =LINEST(A2:A9,B2:B9,,TRUE) in cell A12. After pressing ENTER, you should see –1.4381 in cell A12. This number, the estimated value of b, is the estimated slope of the regression line. 3. Select cells A12 through B14. With Windows Excel, press F2, then CTRL+SHIFT +ENTER.11 With Mac Excel, press CTRL+U, then COMMAND +ENTER. 4. Format cells A12 through B14 to display three decimal places and right-align the numbers, yielding the output shown in the screenshot on the right. 10LINEST uses ordinary least squares to estimate the regression line. The Windows version of Excel also has a simpler method for running OLS regressions, which we describe in the appendix to this chapter. 11CTRL+SHIFT+ENTER means that you press the Ctrl, Shift, and Enter keys simultaneously. 3.3 Properties and Statistical Significance of Estimated Coefficients 65 The estimated value of a, rounded to three decimal places, is in cell B12. The n = 53.857 - 1.438p. The corresponding estiestimated demand curve is therefore Q mated standard errors are in the cells immediately underneath the coefficient estimates. The estimate of b is –1.438 (cell A12), and its estimated standard error is 0.090 (cell A13). The estimate for a is 53.857 (cell B12), and its estimated standard error is 2.260 (cell B13). Cell A14 shows that the R2 is 0.977, which is close to the maximum possible value. This high R2 indicates that the regression line explains almost all the variation in the observed quantity.12 This estimated demand curve can be used to estimate the quantity demanded for any price. According to our estimated demand function, if the price is 27 ($27,000), n = 53.857 - (1.438 * 27) = 15.031 we expect the focus group consumers to buy Q Camrys. We would round this estimate to 15 cars, given that cars are sold in discrete units. However, if this focus group represented a large group, perhaps a thousand times larger (50,000 consumers), the quantity demanded estimate would be 15,031 vehicles. Confidence Intervals We know that an estimated coefficient is not likely to exactly equal the true value. Therefore, it is useful to construct a confidence interval, which provides a range of likely values for the true value of a coefficient, centered on the estimated coefficient. For example, a 95% confidence interval is a range of coefficient values such that there is a 95% probability that the true value of the coefficient lies in the specified interval. The length of a confidence interval depends on the estimated standard error of the coefficient and the number of degrees of freedom, which is the number of observations minus the number of coefficients estimated. In our Camry example, there are eight observations and we estimate two coefficients, so there are six degrees of freedom. 12Cell B14 shows the standard error of the estimated dependent variable. 66 CHAPTER 3 Empirical Methods for Demand Analysis If the sample has more than 30 degrees of freedom, the lower end of a 95% confidence interval is (approximately) the estimated coefficient minus twice its estimated standard error, and the upper end of the interval is the estimated coefficient plus twice its estimated standard error. With smaller sample sizes, the confidence interval is larger.13 With the six degrees of freedom of the Camry demand curve regression, the confidence interval is the estimated coefficient plus or minus 2.447 times the standard error. In this regression, the slope coefficient, bn, on the price is -1.438 and its standard error is 0.090. Therefore, the 95% confidence interval for bn is centered on -1.438 and goes approximately from -1.658 (= -1.438 - [2.447 * 0.090]) to -1.218 (= -1.438 + [2.447 * 0.090]). If the confidence interval is small, then we are reasonably sure that the true parameter lies close to the estimated coefficient. If the confidence interval is large, then we believe that parameter is not very precisely estimated. Typically, the more observations we have, the smaller the estimated standard errors and the tighter the confidence interval. Thus, having a larger data set tends to increase our confidence in our results. Hypothesis Testing and Statistical Significance There are two possible outcomes: if the result confirms the hypothesis, then you’ve made a measurement. If the result is contrary to the hypothesis, then you’ve made a discovery. —Enrico Fermi A manager can use estimated coefficients and standard errors to test important hypotheses. Very often, the crucial issue for a manager is to determine whether a certain variable really influences another. For example, suppose a firm’s manager runs a regression where the demand for the firm’s product is a function of the product’s price and the prices charged by several possible rivals. If the true coefficient on a rival’s price is zero, then the potential rival’s product is not in the same market as the manager’s product, and the manager can ignore that firm when making decisions. Thus, the manager wants to formally test the null hypothesis that the rival’s coefficient is equal to zero. One approach is to determine whether the 95% confidence interval for that coefficient includes zero. If the entire confidence interval for the coefficient on a rival’s price contains only positive values, the manager can be 95% confident that the explanatory variable has a positive effect: the higher the rival’s prices, the greater the demand for the manager’s product. Equivalently, the manager can test the null hypothesis that the coefficient is zero using a t-statistic. The LINEST function does not report t-statistics automatically, but they are easily calculated. The t-statistic equals the estimated coefficient divided by its estimated standard error. That is, the t-statistic measures whether the estimated coefficient is large relative to the standard error. In the Camry example, the t-statistic for the constant or intercept coefficient is 53.857/2.260 ≈ 23.8, and the t-statistic on the price coefficient is -1.438/0.090 ≈ -16.0. If the absolute value of the t-statistic is larger than a critical value, then we know that the confidence interval does not include zero, so we reject the null hypothesis that the coefficient is zero. For samples with more than 30 observations, this critical value is about 2, while in our Camry example it is 2.447. That is, our rule is that we reject the null hypothesis at a 95% level of confidence if the absolute value of the t-statistic exceeds the critical value. An equivalent statement 13The relevant number can be found in a t-statistic distribution table. 3.4 Regression Specification 67 is that, given a t-statistic with a magnitude exceeding the critical value, we will be wrong less than 5% of the time if we reject the hypothesis that the explanatory variable has no effect. The chance that we are wrong when we use a test statistic to reject the null hypothesis is often referred to as the significance level of the hypothesis test. Thus in a large sample, if the t-statistic is greater than about 2, we reject the null hypothesis that the proposed explanatory variable has no effect at the 5% significance level or 95% confidence level. Rather than use this rather convoluted formal statement, many analysts say simply that the explanatory variable is “statistically significant” or “statistically significantly different from zero.” 3.4 Regression Specification An approximate answer to the right problem is worth a good deal more than an exact answer to an approximate problem. —John Tukey The first step in a regression analysis is to select a regression equation. We must determine the regression specification, which includes the choice of the dependent variable, the explanatory variables, and the functional relationship between them (such as linear, quadratic, or exponential). For example, in the Camry demand curve regression, the dependent variable is the quantity of Camrys demanded, the only explanatory variable is price, measured in thousands of dollars, and the functional relationship between the variables is linear: Q = a + bp + e. A regression analysis is valid only if the regression equation is correctly specified. In particular, the specification should include the appropriate explanatory variables, it must closely approximate the true functional form, and the underlying assumptions about the error term should be correct. Selecting Explanatory Variables When selecting variables to include in a regression, we must take care in choosing which explanatory variables to include. The explanatory variables should include all the observable variables that are likely to have a meaningful effect on the dependent variable. We use our understanding of causal relationships, including those that derive from economic theory, to select explanatory variables. In the Camry focus group example, we used our knowledge of demand theory to conclude that the price was likely to affect the quantity demanded. M ini-Case It is unfortunate we can’t buy many business executives for what they are worth and sell them for what they think they are worth. —Malcolm Forbes Determinants of CEO Compensation Human resources managers often use regression studies to determine if their employees are paid comparably with other firms.14 Similarly, during the major economic crisis of 2007–2009 the very high compensation that chief executive officers (CEOs) of major corporations received were a source of much controversy, and many large banks and other corporations were under pressure to provide evidence to justify their payments. We use multivariate regression to analyze the determinants of CEO compensation. We use economic theory and 14Another use is in union negotiations. One of us was retained by a large firm to perform a regression analysis to determine how their unionized employees’ wages compared to wages of comparable unionized and nonunionized workers in other firms. The firm used this study to bargain with its union. 68 CHAPTER 3 Empirical Methods for Demand Analysis previous studies to choose the variables that we believe are important determinants of CEO compensation. Then, we test whether these variables belong in the equation. In our regression analysis, we use data from Standard & Poor’s Compustat database on CEO compensation for the 1992–2010 period for corporations in the S&P 500, which is Standard & Poor’s list of the 500 largest publicly traded U.S. corporations. We have over 6,200 observations in our data set, where the dependent variable in each observation is the CEO’s annual compensation in a particular S&P 500 corporation in a particular year, along with the values of the proposed explanatory variables. Well over half of this compensation was in the form of stock options, which give the holder the right to buy stock in the company at an attractive price far below the market value. The rest consisted primarily of salary and bonuses. In our multivariate regression, the dependent variable, Y, is CEO compensation in thousands of dollars. We expect the compensation to be greater for CEOs who manage large firms because that requires more work and responsibility. We use two measures of firm size: assets, A (in $ billions), which are related to the firm’s capital input, and employees, L (thousands of workers). Presumably a CEO is paid more when the company does well. One measure of a company’s success is shareholders’ average return over the previous three years, S. This return includes dividends, which are direct payments to shareholders, and capital gains, which are increases in the value of the shares of the shareholders. A CEO may also be worth more to a firm as the CEO’s experience, X (the number of years that the CEO has held this job), rises. We use ordinary least squares to estimate a multivariable regression equation that relates a CEO’s salary to these explanatory variables: Y = a + bA + cL + dS + fX + e, where a is a constant and the other coefficients show how much a one unit increase in the corresponding explanatory variable affects CEO compensation. For example, one extra unit (thousand) of employees raises the CEO salary by c. The estimated compensation as a function of the explanatory variables is Yn = -377 + 3.86A + 2.27L + 4.51S + 36.1X, as the following table of regression results shows. CEO Compensation Regression Results Explanatory Variable Constant Coefficient Standard Error t-Statistic -377 462 - 0.82 Assets ($billions), A 3.87 0.70 5.52* Employees (000s), L 2.26 0.51 4.48* Shareholder return, S 4.51 1.42 3.17* Experience (years), X 36.10 8.49 4.25* * indicates that we can reject the null hypothesis that the coefficient is zero at the 5% significance level. Based on these t-statistics, we reject the null hypothesis that the coefficients on our four variables are zero at the 5% significance level. Each of these four 3.4 Regression Specification 69 t-statistics is larger than 2. For example, the t-statistic on the total assets coefficient is 5.52, which is substantially larger than 2. Thus, we conclude that these variables belong in our specification. The estimated effect of increasing total assets by $1 billion is to increase the CEO’s compensation by $3,870 ($3.87 thousand). If average annual shareholder return over three years increases by one percentage point (say, rising from 8% to 9% per year), a CEO’s compensation is higher by $4.51 thousand. Although these variables are statistically significantly different than zero, not all of them are economically significant. That is, they do not have a large impact on CEO compensation. For example, the effect of the company’s financial performance— shareholders’ average return—on CEO salary is relatively small. Most S&P 500 companies have equity values of several billion dollars or more. An increase in shareholder return of one percentage point would apply to the overall equity value and would therefore imply additional returns to shareholders of tens of millions of dollars. However, the difference in CEO salary would be only a small amount (from a CEO’s point of view) of less than $5,000 per year. Thus, although the shareholder return variable is statistically significant, it is not very important to a CEO’s compensation. Q& A 3.4 In the Mini-Case just considered, what is the estimated effect of more employees on CEO compensation? Is this effect statistically significant? Answer 1. Use the regression coefficient in the estimated CEO compensation function to identify the estimated effect of more employees. The regression table in the CEO compensation Mini-Case shows that if a firm’s workforce increases by 1,000 employees, the CEO’s compensation is estimated to rise by about $2.26 thousand per year. 2. Use the t-statistic shown in the regression table to assess statistical significance. The t-statistic for the employees is 4.48. The asterisk in the table indicates that this coefficient is significantly different from zero at the 5% significance level, which is the normal standard applied to infer that a coefficient is statistically significant. Thus, we can say that the number of employees is estimated to have a statistically significant effect on CEO compensation. Correlation and Causation. When selecting explanatory variables, it is important to distinguish between correlation and causation. Two variables, X and Y, are said to be correlated if they move together. The quantity demanded and price are negatively correlated: when price goes up, quantity goes down. This correlation is causal as changes in price directly affect the quantity demanded. However, correlation does not necessarily imply causation. For example, sales of gasoline and the incidence of sunburn have a strong positive correlation in U.S. data. Both are relatively high in the summer months of July and August and low in winter months. 70 CHAPTER 3 Empirical Methods for Demand Analysis Does this correlation mean that a sunburn somehow increases a consumer’s demand for gasoline? Should we use the incidence of sunburn as an explanatory variable for gasoline demand? The answer to both these questions is no. The correlation between gasoline sales and sunburn is caused mainly by a third variable, sunshine. During sunny summer months people drive more, in part because they take more vacations that involve driving. They also spend more time in the sun and are therefore more likely to get sunburned. If our gasoline demand regression equation included the incidence of sunburn as an explanatory variable, we would find a high R2 statistic and a statistically significant positive coefficient on sunburn. However, these results would be spurious. Any interpretation that getting sunburned increases the demand for gasoline would be incorrect. Thus, it is critical that we do not include explanatory variables that have only a spurious relationship to the dependent variable in a regression equation. In estimating gasoline demand we would include price and income as explanatory variables, and we might include sunshine hours or temperature, but we would not include sunburn incidence as an explanatory variable. If there is a causal relationship between two variables, it is important that we treat the causal variable as the explanatory variable. Suppose that a store selling umbrellas collects weekly data on rainfall and on umbrella sales. It would be incorrect to run a regression with umbrella sales as the explanatory variable and rainfall as the dependent variable. While such a regression would likely yield a statistically significant coefficient on umbrella sales, it makes no sense to think of umbrella sales as affecting rainfall.15 Because rainfall increases the demand for umbrellas, rainfall should be the explanatory variable and the demand for umbrellas should be the dependent variable. Omitted Variables. Often, a manager has an otherwise appropriately specified regression but lacks information about one or more potential explanatory variables. Because these variables are not included in the regression specification, they are called omitted variables. If a key explanatory variable is missing, then the resulting coefficient estimates and hypothesis tests may be unreliable. Suppose Jacob and Santiago are managers in the same firm. Jacob wants to estimate the effect of price on quantity demanded and therefore experiments with the price over some time interval, starting with a low price and trying successively higher prices as time proceeds. Santiago, on the other hand, is interested in the effect of advertising on demand and—without telling Jacob—varies the advertising level over the same time interval, starting with a low advertising level and moving to a high level as time passes. Because the higher prices offset the increased advertising activity, the quantity demanded stays fairly stable. 15Of course, many people believe that the failure to carry an umbrella causes rain. 3.4 Regression Specification 71 Because Jacob does not know about the advertising experiment, after he regresses quantity on price, he is amazed to discover that price increases have no effect on demand. Clearly a regression of quantity demanded on price alone would be highly misleading in this situation, leading Jacob to an incorrect conclusion about the firm’s demand curve. If only the price increase occurred, the quantity demanded would have fallen. In this example, it is important to include both price and advertising as explanatory variables. Functional Form So far, we have assumed that our regression equations were linear. However, we cannot assume that demand curves or other economic relationships are always linear. Choosing the correct functional form may be difficult. One useful step, especially if there is only one explanatory variable, is to plot the data and the estimated regression line for each functional form under consideration. We illustrate this approach with an advertising example. A large food manufacturing firm sells its products in many cities throughout the country. To determine the importance of advertising, it holds its price constant across cities but varies the number of commercials per week on local television in each city.16 Figure 3.6 shows the relationship between the quantity demanded and advertising, holding price and other relevant explanatory variables constant. Both panels contain the same data points. The vertical axis shows the quantity demanded per family per week, and the horizontal axis is the number of commercials per week on local television. The two panels have different estimated regression lines based on different functional form specifications. Panel a shows an estimated linear regression, which is based on the assumption that the relationship between the quantity demanded and advertising is linear: Q = a + bA + e, where Q is quantity demanded, A is a F IG U RE 3. 6 The Effect of Advertising on Demand (a) Linear regression line (b) Quadratic regression Q, Per week Q, Per week The linear regression line in panel a does not fit the data points as well as does the quadratic curve in panel b. 15 10 15 10 5 5 0 2 4 6 8 10 12 14 16 18 A, Commercials per week 0 2 4 6 8 10 12 14 16 18 A, Commercials per week 16For example, Campbell Soup Company has conducted these types of experiments (Eastlack and Rao, 1989). 72 CHAPTER 3 Empirical Methods for Demand Analysis measure of the amount of advertising, e is a random error term, and a and b are the parameters to be estimated. Panel b shows an estimate based on a quadratic regression specification: Q = a + bA + cA2 + e. The only difference between this specification and the linear specification is that we have added an extra term, the coefficient c times the advertising index squared: cA2. If c ≠ 0, the plot of the relationship between Q and A is a curve. If c = 0, this extra quadratic term drops out and the equation reverts to a linear form. Therefore, the test of whether c is statistically significantly different from zero can be used as a test of whether the quadratic form is better than the linear form. Table 3.2 shows OLS estimates of both the linear and quadratic specifications. The estimation of the linear specification does not look bad when considered by itself. The coefficient on advertising is statistically significantly different from zero, and the R2 is 0.85, which implies that the line “explains” most of the variation in quantity. However, the data points in panel a of Figure 3.6 are not randomly distributed around the regression line. Instead, they are first below the line, then above the line, and then below the line again. This pattern of residuals signals that the linear model is not the proper specification. The estimated quadratic specification fits the data much better than the linear model: R2 = 0.99. All the coefficients are statistically significantly different from zero. In particular, cn, the estimated coefficient on A2, is statistically significant, so we reject the linear specification. The data points appear randomly distributed around the quadratic regression curve in panel b of Figure 3.6. Because the quadratic functional form allows for a curved relationship between quantity and advertising, it captures two important phenomena that the linear specification misses. First, at high levels of advertising intensity, it becomes increasingly difficult to generate more demand, as virtually all potential consumers have purchased the product. The market becomes saturated: no more consumers can be convinced to buy the product. This saturation effect is captured by the declining slope of the regression line in panel b. The linear specification misses this effect. Second, the linear form overstates the amount of demand that would occur at very low levels of advertising. If advertising activity is very low, small increases have a large payoff—an effect that is captured by the quadratic functional form but not by the linear functional form. A manager using the linear form to assess what would happen at either very high levels or very low levels of advertising would make a serious mistake. And even at intermediate levels of advertising, the linear TA B L E 3. 2 Regressions of Quantity on Advertising Linear Specification Coefficient Quadratic Specification Standard Error t-Statistic Coefficient Standard Error t-Statistic Constant 5.43 0.54 10.05* 3.95 0.30 13.18* Advertising, A 0.53 0.06 8.47* 1.20 0.10 12.18* - 0.04 0.01 - 7.05* Advertising, A2 *indicates that we can reject the null hypothesis that the coefficient is zero at the 5% significance level. 3.4 Regression Specification 73 regression model would consistently understate demand, albeit by only a modest amount. Although we have focused on linear and quadratic functional forms, there are many other possible functional forms that might be relevant in some circumstances. Selecting among possible functional forms is an important part of regression analysis. In this example, we were able to formally test whether to use a quadratic functional form or a linear functional form in the regression specification. However, it is not always possible to compare functional forms in this way, and it may be necessary to use advanced statistical techniques covered in statistics or econometrics courses to assist in making decisions about functional form specification. Ma nagerial I mplication Experiments If your result needs a statistician then you should design a better experiment. —Ernest Rutherford (Nobel Prize-winning chemist and physicist) Given the challenges in obtaining data and producing a regression that is properly specified, many firms turn to controlled experiments. For example, a firm can vary its price and observe how consumers react. Unfortunately, firms cannot control all important elements of an experiment as is done in a chemistry or physics lab. As a result, firms often use regressions to hold constant some variables that they could not control explicitly and to analyze their results. In 1988, the credit card company Capital One was founded with the plan to apply experimental methods to all aspects of its business.17 For example, if the company wanted to know whether a credit card solicitation would be more successful if mailed in a blue envelope or in a white one, it ran an experiment. By 2000, Capital One was running more than 60,000 tests per year. Similarly, Harrah’s Entertainment relies on randomized tests of various hypotheses to design its marketing. It might send an attractive hotel offer for a Tuesday night to a randomly selected group of customers, and compare the response for that test group to other customers who serve as a control group. The Internet now allows many firms to run very low-cost experiments involving tens of thousands of customers. During the 2012 U.S. presidential election, the Obama campaign ran experiments on each type of e-mail fundraising solicitation it used. Google ran about 12,000 randomized experiments in 2009 alone. Google has posted on its website illustrations of how a firm can run randomized experiments on the effectiveness of advertising while controlling for geographic or other differences. In an associated article, Google illustrates one such experiment and the linear regression models they used to analyze it and the hypothesis tests they conducted.18 Managers should take advantage of the low cost of Internet experiments. 17The following examples are from Jim Manzi, “What Social Science Does—and Doesn’t—Know,” www.city-journal.org/2010/20_3_social-science.html, Manzi (2012), and Jon Vaver and Jim Koehler, “Measuring Ad Effectiveness Using Geo Experiments,” services.google.com/fh/files/blogs/geo_ experiments_final_version.pdf. 18See services.google.com/fh/files/blogs/geo_experiments_final_version.pdf. 74 CHAPTER 3 3.5 Empirical Methods for Demand Analysis Forecasting Predictions about the future are often referred to as forecasts. Managers frequently seek forecasts of important variables related to demand such as sales or revenues. Large banks and other financial institutions commonly make forecasts regarding macroeconomic variables such as interest rates, gross domestic product, unemployment, and inflation. Governments make forecasts of revenues, expenditures, and budget balances, among other things, and we are all familiar with weather forecasts. There are many different methods of forecasting. We concentrate on two commonly used regression-based methods of forecasting: extrapolation and theorybased econometric forecasting.19 Extrapolation Extrapolation seeks to forecast a variable of interest, like revenue or sales, as a function of time. Extrapolation starts with a series of observations collected over time, referred to as a time series. For example, a firm might have monthly sales data for a new product for several years and be interested in projecting future sales based on this historical data. In extrapolation, the time series is smoothed in some way to reveal the underlying pattern, and this pattern is then extended or extrapolated into the future to forecast future sales. This type of forecasting is called pure time-series analysis because it seeks to forecast future values of some variable, like sales, purely on the basis of past values of that variable and the passage of time. Trends. Most of us automatically use our eyes to fit a trend line when we look at a plot of data points over time. We now use a regression technique to plot such a trend line formally. Figure 3.7 shows the quarterly revenue ( = price times quantity) for Heinz, which is famous for its most important product, ketchup.20 The figure plots the quarterly data from the first quarter of 2005 through the fourth quarter of 2011. Heinz could estimate its revenue, R (in millions of dollars), as a linear function of time, t, which equals 1 in the first quarter of 2005, 2 in the second quarter, and follows this pattern through 28 in the last quarter. The linear regression equation is R = a + bt + e, where e is the error term and a and b are the coefficients to be estimated. The estimated trend line is R = 2,089 + 27.66t, where the coefficient on the time trend is statistically significant. This line is plotted in Figure 3.7. Based on this regression, Heinz could forecast its sales in the first quarter of 2014, which is quarter 19An alternative approach is to rely on subjective judgments. One judgment-based approach is the Delphi technique. A group of experts are asked to make initial forecasts, which are then made known to the group, and the reasoning behind them is discussed. The experts then make new forecasts, and the process is repeated until broad consensus is reached or until the differences in opinion have converged as much as reasonably possible. The resulting forecasts reflect the collective judgment of the group. 20The data are from Heinz’s annual reports. For financial reporting Heinz defines its quarters as the three-month periods ending in April, July, October, and January. We refer to the quarter ending in April as the first quarter, the quarter ending in July as the second quarter, and so forth. These data refer to worldwide revenues, about half of which come from North America. 3.5 Forecasting 75 F IG U RE 3. 7 Heinz’s Quarterly Revenue: 2005–2012 Revenue, $ millions Each point shows Heinz’s revenue in millions of dollars for a particular quarter. A regression is used to fit a trend line through these points. The dashed portion of the line indicates a forecast. The red point at the end of the trend line shows the forecast revenue for the first quarter of 2014. 3,200 2,700 1,700 2005 q1 q2 q3 q4 2006 q1 q2 q3 q4 2007 q1 q2 q3 q4 2008 q1 q2 q3 q4 2009 q1 q2 q3 q4 2010 q1 q2 q3 q4 2011 q1 q2 q3 q4 2012 q1 q2 q3 q4 2013 q1 q2 q3 q4 2014 q1 2,200 Quarter Source: Heinz’s Annual Reports. 37, as 2089 + (27.66 * 37) ≈ $3,112 million ($3.112 billion), which is the red point at the right end of the trend line. Of course, the further into the future we forecast, the less reliable is the forecast.21 Seasonal Variation. If we look at the trend line through the data in Figure 3.7, we notice a distinct pattern of the observations around the trend line. If this variation were purely random, there would not be much we can do about it except to note that our forecasts have potential random errors associated with them. However, because this pattern looks systematic, we may be able to adjust for it. The revenue in the first quarter (late winter and early spring) tends to be above the trend line, while the second quarter tends to be below the trend line, and so forth. It appears that there is a seasonal variation in demand for Heinz’s products. In making forecasts, we should adjust for these seasonal effects. We can add variables to our regression that capture the seasonal effects. These variables, often called seasonal dummy variables, are variables that equal one in the relevant season and zero otherwise. For example, the first quarter dummy variable is one in the first quarter of the year and zero in the other quarters. We include these indicator variables for 21Some academics argue that the managers of the U.S. Social Security Administration have made inaccurate forecasts, so that the system will go bankrupt (if nothing is done) earlier than the managers forecast: www.nytimes.com/2013/01/06/opinion/sunday/social-security-its-worse-than-youthink.html?_r=0. 76 CHAPTER 3 Empirical Methods for Demand Analysis only three quarters. The fourth quarter is then interpreted as the base case, and the coefficient on each of the other quarters shows us the difference between that quarter and the base case. We estimate R = a + bt + c1D1 + c2D2 + c3D3 + e, where D1, D2, and D3 are quarterly dummy variables for the first three quarters: those ending in April, July, and October. The new estimated equation is R = 2,094 + 27.97t + 93.8D1 - 125.3D2 - 8.60D3, where all the coefficients are statistically significant. Our failure to include the seasonal dummy variables in our original regression may have led to a biased estimate. Based on this new regression model, the forecast value for the quarter ending in January of 2014 is 2094 + (27.97 * 37) + (93.8 * 1) - (125.3 * 0) - (8.60 * 0) = $3,223 million. This adjusted forecast is about $111 million (about 3.5%) more than our previous forecast that ignored seasonal effects. Properly incorporating seasonal effects allows us to adjust for the fact that revenues tend to be higher in the first quarter than in other quarters. Nonlinear Trends. Although Heinz’s revenue follows a linear trend, not all time trends are linear. For example, the market penetration of new products is often nonlinear. After it is first introduced, a new product’s market share often grows slowly, as it takes a while for consumers to become familiar with the product. At some point, a successful product takes off and sales grow very rapidly. Then, when the product eventually approaches market saturation, sales grow slowly in line with underlying population or real income growth. Ultimately, if the product is displaced by other products, its sales will fall sharply. For example, sales of iPod units followed this pattern. Theory-Based Econometric Forecasting Revenue is determined in large part by the consumers’ demand curve. We know that the demand is affected by variables such as income, population, and advertising. Yet our forecast based on extrapolation (pure time-series analysis) ignored these structural (causal) variables. The role of such variables may be implicit in an extrapolation. For example, one reason why revenue may have grown smoothly over time is that population increased smoothly over this time period. As a first approximation, extrapolation is often useful, especially if seasonal effects are properly addressed. However, the problem with such forecasts is that they are not based on a causal understanding of how the variable of interest is actually determined. As a result, it is difficult for the forecaster to understand the underlying causal structure that determines revenue and to anticipate the effects of changes in causal variables such as income or population. If we are interested in underlying economic structure, a different approach is needed. An alternative forecasting approach uses economic theory, such as a demand framework, to derive the causal relationships between economic variables. For example, in forecasting Heinz’s sales or revenue, we could estimate the effect of changes in income on demand for Heinz’s products and then take the expected pattern of income growth into account in forecasting sales. Forecasts based on a regression specification that incorporates underlying causal factors is called causal econometric forecasting or theory-based econometric forecasting. Such forecasting methods incorporate both extrapolation and estimation of causal or explanatory economic relationships. Thus to forecast sales, we might use both previous values of sales and time as explanatory variables, and we would also use 3.5 Forecasting 77 causal variables such as income. That is, with theory-based (causal) econometric forecasting, we predict the dependent variable based on the underlying causal factors—not just on the time-series pattern of the dependent variable. We use these estimates to make conditional forecasts, where our forecast is based on specified values for the explanatory variables. For example, a manager might make one conditional forecast of sales based on the assumption that income will be 5% higher next quarter than this quarter and another conditional forecast based on the assumption that income next quarter will be the same as this quarter. In our extrapolation analysis, we assumed that Heinz’s revenue would grow steadily over time. However, there are underlying causal or structural factors that might affect its revenue. We would expect Heinz’s revenue to deviate from the trend line if a rival entered or exited the business, if Heinz added a new major product to its product line or acquired another large company, if the cost of transportation or ingredients changed dramatically, or if the country went into a major recession. Heinz could regress its revenue on these economic factors. It could then use that regression to make forecasts that are conditional on how it expects these other factors to evolve over time. Forecasting using theory-based econometric modeling is more difficult than employing extrapolation. However, it often provides a better chance of identifying sudden deviations from a simple trend line, and it may contribute more to a firm’s understanding of the underlying business interactions. Ma nagerial So l ution Estimating the Effect of an iTunes Price Change How could Apple use a focus group to estimate the demand curve for iTunes to determine if raising its price would raise or lower its revenue? To answer this question, we asked a focus group of 20 Canadian college students in 2008 how many popular tracks they downloaded from iTunes when the price was 99¢ and how many they would have downloaded at various other prices assuming that their incomes and the prices of other goods remained constant. The responses were: Price, $ per song Quantity, Songs per year 1.49 441 1.29 493 1.19 502 1.09 536 0.99 615 0.89 643 0.79 740 0.69 757 0.49 810 The iTunes managers would first estimate a linear demand curve of song downloads on price, obtaining demand coefficient estimates, the R2 statistic, and standard errors, and then calculate the t-statistics (dividing each coefficient by its standard error). n = 1,024 - 413p, Based on these results, the estimated linear demand curve is Q n where Q is the estimated number of downloads per year and price p is in dollars per song. The price coefficient is -413, which means that a $1 increase in price 78 CHAPTER 3 Empirical Methods for Demand Analysis would reduce estimated quantity demanded by 413 downloads. Converting this result to cents, a 1¢ increase in price would reduce estimated quantity demanded by 4.13 downloads per year. The t-statistic is -12.6, so this coefficient is significantly different from zero. The R2 statistic is 0.96, indicating that the regression line fits the data closely. Apple’s manager could use such an estimated demand curve to determine how revenue, R, which is price times quantity (R = p * Q), varies with price. Panel a of Figure 3.8 shows the estimated iTunes demand curve. At p = 99¢, 615 songs were downloaded by the focus group according to this estimated demand curve. The corresponding revenue is the rectangle consisting of areas A + B. The height of this rectangle is the price, p = 99¢. The length of the rectangle is the quantity of songs downloaded, Q = 615, so the area of the rectangle equals R = p * Q = $0.99 * 615 ≈ $609. If the price were increased to $1.24, the quantity demanded would drop to 512. The corresponding revenue would be the rectangle = A + C, where the height is $1.24 and the length is 512. According to the focus group’s responses, Apple would lose revenue equal to area B but gain area C. Area B shows how much Apple loses from selling 103 (= 615 - 512) fewer units at the original price. Area C is the extra amount it makes on the 512 units it does sell, because it sells each song by $0.25 (= $1.24 - $0.99) more than it did originally. An increase in price has two offsetting effects on revenue. Revenue tends to fall because the price increase causes fewer units to be sold. However, revenue tends to rise because a higher price is collected on every unit that is sold. Because these two effects have opposite effects on revenue, management would not know in general whether a particular price increase would raise or lower revenue. However, because we have estimated the demand curve, we can calculate the size of these two effects and determine the net effect of a price increase on iTunes’s revenue. The lost revenue from fewer sales is area B, which is $102. The revenue gain due to the higher price on the units sold is area C, which is $128. Therefore, revenue increases by $26 ( = $128 - $102). Panel b corresponds to panel a. Its horizontal axis measures quantity as in panel a, but its vertical axis measures revenue (rather than price as in panel a). Panel b shows the revenue curve, which relates revenue to the quantity sold.22 At the original price of 99¢, where Q = 615, the revenue curve shows that revenue is $609, consistent with panel a. This curve shows that the revenue curve reaches its maximum at $1.24. Given that the cost to Apple of selling an extra song is probably very close to zero, it seems that Apple would like to maximize its revenue. If the general population has similar tastes to the focus group, then Apple’s revenue would increase if it raised its price to $1.24 per song.23 the estimated demand curve is Q = 1,024 - 413p, the corresponding inverse demand curve is p ≈ 2.48 - 0.00242Q. Thus, the revenue function is R = p * Q ≈ 2.48Q - 0.00242Q2. 23See the Mini-Case “Available for a Song” in Chapter 10 for a larger-scale, more detailed study of Apple’s pricing. 22Because 3.5 Forecasting 79 F IG URE 3. 8 iTunes Focus Group Demand and Revenue Curves = $0.99* 615. At a price of $1.24, the songs demanded would fall to 512, and the revenue would be areas A + C = $507+ $128 = $635 = p * Q = $1.24 * 512. (b) According to the corresponding revenue curve, revenue is greatest for this focus group at p = $1.24, where R = $635. Based on a focus group’s responses, we estimate the iTunes demand curve and calculate a revenue (= price * quantity) curve. (a) According to the estimated demand curve, if the price were 99¢, the focus group would download 615 songs per year and revenue would be areas A + B = $507 + $102 = $609 = p * Q p, $ per song (a) Demand Curve Demand e2 1.24 C = $128 e1 0.99 A = $507 0 B= $102 512 615 512 615 1,024 Q, Songs per year R, Revenue, $ per year (b) Revenue Curve 635 609 Revenue 0 1,024 Q, Songs per year 80 CHAPTER 3 Empirical Methods for Demand Analysis S U MMARY 1. Elasticity. An elasticity shows how responsive one variable is to changes in another variable. The price elasticity of demand, ε, summarizes how much the quantity demanded changes when the price changes. The responsiveness of quantity is related to the shape of a demand curve at a particular point or over a particular interval. Specifically, the price elasticity of demand is the percentage change in the quantity demanded divided by an associated percentage change in price. For example, a 1% increase in price causes the quantity demanded to fall by ε%. Downward-sloping demand curves have a negative elasticity. The demand curve is perfectly inelastic if ε = 0, is inelastic if ε is between 0 and -1, has unitary elasticity if ε = - 1, is elastic if ε 6 - 1, and becomes perfectly elastic as ε approaches negative infinity. The quantity demanded varies less than in proportion to a 1% change in the price if the demand curve is inelastic, but varies more than in proportion if the demand curve is elastic. The elasticity of demand varies along a downward-sloping linear demand curve. A vertical demand curve is perfectly inelastic and a horizontal demand curve is perfectly elastic. 2. Regression Analysis. Regression analysis fits an economic relationship to data. It explains variations in a dependent variable, such as the quantity demanded, using explanatory variables, such as price and income. A linear regression with just one explanatory variable corresponds to putting the dependent variable on the vertical axis, the explanatory variable on the horizontal axis, plotting the data points, and drawing the “best possible” straight line through these points. One method used to find a suitable estimated relationship is ordinary least squares (OLS), which chooses parameter estimates or “draws the regression line” such that the sum of squared deviations of the data points from the regression line is as small as possible. To help assess the fit of the regression line to the data, statistical packages report the R2 statistic, which is the fraction of the actual variation in the dependent variable explained by the estimated regression equation. 3. Properties and Statistical Significance of Estimated Coefficients. A good estimation method should yield coefficient estimates that are unbiased—that would average out to the true value in repeated samples. It is also desirable that an estimation method does not produce very different coefficient estimates in different random samples. Regression software produces statistics that can be used to assess how much confidence to place in regression coefficient estimates. Standard errors tell us how much we might expect coefficient estimates to differ from their true values. A t-statistic allows us to test whether an estimated regression coefficient is different from zero. We obtain a t-statistic for each coefficient by dividing the coefficient by its standard error. If the t-statistic exceeds a critical value that is approximately equal to 2, we can be confident that the coefficient differs from zero. 4. Regression Specification. Regression analysis is reliable only if the equation to be estimated is properly specified. One important aspect of specification is that all relevant explanatory variables should be included. A second specification issue is that a regression equation must have an appropriate functional form. Excluding relevant explanatory variables, including inappropriate explanatory variables, or using the wrong functional form can lead to misleading results. 5. Forecasting. One method of forecasting is to extrapolate a time series into the future. As a first step in extrapolation, a manager can regress the variable to be forecast, such as sales, on a timetrend variable. Next, using the estimated trend line, a manager can forecast the future value by substituting future times into the estimated regression equation. When extrapolating, it is often necessary to adjust for seasonal or other patterns. A second method of forecasting uses causal economic relationships, where economic variables are used as explanatory variables instead of or in addition to a time trend. Here, forecasting the dependent variable may require the manager to use expected values of the explanatory variables. Questions 81 Q U E S T ION S All exercises are available on MyEconLab; * = answer at the back of this book; C = use of calculus may be necessary. 1. Elasticity 1.1. The U.S. Tobacco Settlement between the major tobacco companies and 46 states caused the price of cigarettes to jump 45¢ (21%) in November 1998. Levy and Meara (2005) found only a 2.65% drop in prenatal smoking 15 months later. What is the elasticity of demand for this group? 1.2. When Apple raised the price of iTunes from 99¢ to $1.29, GS Boyz’s “Stanky Legg” sales dropped from 22,686 units to 19,692 units (Glenn Peoples, “iTunes Price Change: Sales Down, Revenue Up in Week 1,” Billboard, April 15, 2009). What was the song’s arc elasticity of demand? (Hint: See Q&A 3.1.) *1.3. The demand curve for a good is Q = 100 - 2p. What is the elasticity at the point p = 10 and Q = 80? 1.4. Luchansky and Monks (2009) estimated that the U.S. demand curve for ethanol is Q = p-0.504p1.269 v2.226, g where Q is the quantity of ethanol, p is the price of ethanol, pg is the price of gasoline, and v is the number of registered vehicles. What is the elasticity of demand for ethanol? (Hint: See Q&A 3.2.) C 1.5. The demand curve for a good is Q = 1,000 - 2p2. What is the elasticity at the point p = 10 and Q = 800? C 1.6. What section of a straight-line demand curve is elastic? *1.7. According to Duffy-Deno (2003), when the price of broadband access capacity (the amount of information one can send over an Internet connection) increases 10%, commercial customers buy about 3.8% less capacity. What is the elasticity of demand for broadband access capacity for these firms? Is demand at the current price inelastic? 1.8. Suppose that the demand curve for wheat in each country is inelastic up to some “choke” price p*—a price so high that nothing is bought—so that the demand curve is vertical at Q* at prices below p* and horizontal at p*. If p* and Q* vary across countries, what does the world’s demand curve look like? Discuss how the elasticity of demand varies with price along the world’s demand curve. *1.9. Calculate the price and cross-price elasticities of demand for coconut oil. The coconut oil demand function (Buschena and Perloff, 1991) is Q = 1,200 - 9.5p + 16.2pp + 0.2Y, where Q is the quantity of coconut oil demanded in thousands of metric tons per year, p is the price of coconut oil in cents per pound, pp is the price of palm oil in cents per pound, and Y is the income of consumers. Assume that p is initially 45¢ per pound, pp is 31¢ per pound, and Q is 1,275 thousand metric tons per year. 1.10. Using the coconut oil demand function from Question 1.9, calculate the income elasticity of demand for coconut oil. (If you do not have all the numbers necessary to calculate numerical answers, write your answers in terms of variables.) 1.11. The Mini-Case “Substitution May Save Endangered Species” describes how the equilibrium changed in the market for seal genitalia (used as an aphrodisiac in Asia) when Viagra was introduced. Use a supplyand-demand diagram to illustrate what happened. Is it possible for a positive quantity to be demanded at various prices, yet nothing is sold in the market? 1.12. Nataraj (2007) found that a 100% increase in the price of water for heavy users in Santa Cruz, California, caused the quantity of water they demanded to fall by an average of 20% (Mini-Case “Turning Off the Faucet”). Before the increase, heavy users initially paid $1.55 per unit, but afterward they paid $3.14 per unit. What can you say about the elasticity of demand? In percentage terms, how much did their water expenditure (price times quantity)—which is the water company’s revenue—change? 2. Regression Analysis 2.1. At the Portland Fish Exchange, each day some amount of cod is brought to market. Supply is perfectly inelastic at that amount. How much cod is caught and brought to market varies day to day. Assuming the demand curve does not vary over time, use the supply-demand framework to illustrate how the price is determined on different days. Explain how this process allows us to identify different points on the demand curve. 2.2. Suppose that a restaurant uses a focus group of regular customers to determine how many customers would buy a proposed new menu item at various prices. Can this information be used to estimate an inverse demand curve? A demand curve? Explain briefly. Would it be possible to use a focus group to generate data that could be used to estimate a 82 CHAPTER 3 Empirical Methods for Demand Analysis demand function including both price and income as explanatory variables? *2.3. The estimated demand curve for popsicles on a particular beach on a sunny summer day is given by Q = 130 - 3.5p, where p is measured in dollars. What is the predicted quantity if p = $2.00. If the actual quantity demanded is 129, what is the residual? Suggest at least two unobserved variables incorporated in the random error. (Hint: See Q&A 3.3.) 2.4. A producer of outdoor clothing used a focus group to obtain information about the demand for fleece jackets with built-in, battery-operated warming panels. At prices of $100, $90, $80, $70, $60, and $50, the focus group demanded 23, 31, 40, 44, 48, and 60 jackets, respectively. Use the Excel Trendline option to estimate a linear demand function and to determine the associated R2 statistic. (Hint: Put price in the first column. Price will appear on the horizontal axis in this case.) 3. Properties and Statistical Significance of Estimated Coefficients 3.1. Using the data in Table 3.1, estimate the cod demand function if we use only the first seven observations. 3.2. How sensitive are your regression results in Exercise 3.1 to small changes in the data? In particular, how do your regression results change if a. The quantity in the first row of Table 3.1 were 2.0 instead of 1.5? b. The quantity in the second row of Table 3.1 were 2.7 instead of 2.2? *3.3. In the Camry focus group analysis in this chapter, we used a regression to estimate the demand for Camrys. Using that equation, how many fewer Camrys would the focus group buy if the price were increased by $1,000? How many Camrys would we expect the focus group to purchase if the price is $20,000? What is the elasticity of demand if the price is $20,000? 3.4. Using the data in Question 2.4, determine the standard error and t-statistic for the price coefficient. Is price statistically significantly different from zero at the 0.05 level of significance? (Hint: Use Excel’s LINEST tool or, if you have the Windows version, the Regression tool.) 4. Regression Specification 4.1. According to the regression results for CEO compensation, is the effect of experience on CEO compensation statistically significant? Is it economically significant? Explain. (Hint: See Q&A 3.4.) 4.2. Suppose that you believe that the demand curve is a constant-elasticity demand curve: Q = Apε, where A is a positive constant and ε is the constant elasticity of demand. You have some data and want to estimate the constant-elasticity demand curve Q = Apεu, where A is a positive constant, ε is the constant elasticity of demand, and u is an error term. Take logarithms of both sides of this equation and show that you get an equation that is linear in logarithmic terms (called a log-linear equation). Explain how you can estimate this equation in Excel or other programs using the OLS techniques that we have discussed. *4.3. You work for a firm producing fitness equipment. You have been told that the demand curve for the firm’s main product—a multistation home gym— is linear. You have been provided with price and quantity data obtained from focus groups and have been asked to run a regression of revenue on price. Should you use a linear functional form—with revenue as a linear function of price—or something else? Explain. 5. Forecasting 5.1. Heinz makes most of its money from ketchup and prepared, packaged foods that are substitutes for fresh foods. From Figure 3.7, we see that its revenue tends to be low in the second quarter (May, June, and July). Can you provide a possible reason for this pattern? (Hint: Fresh fruits and vegetables are substitutes for many of Heinz’s prepared foods, and ketchup is commonly used on foods prepared at outdoor cookouts.) 5.2. As reported in the chapter, quarterly revenue for Heinz is estimated as R = 2,094 + 27.97t + 93.8D1 - 125.3D2 - 8.60D3. What does this estimation tell us about second quarter revenues for Heinz? If, as a consultant, you were asked to suggest ways of smoothing quarter-to-quarter revenues for Heinz, what would you suggest? 5.3. Some companies, such as Heinz, can reliably forecast revenues using pure time-series analysis (that is, by extrapolation of prior data, accounting for seasonal effects). Other companies, such as FedEx (which makes money by shipping packages), or Sony (which sells consumer electronics), find that they cannot rely on pure time-series analysis for reliable forecasting. They are strongly affected by recessions and need to use theory-based methods, including such explanatory variables as income in their forecasting models. Why are they different from Heinz? Questions 6. Managerial Problem 6.1. In the Managerial Solution, we estimated a focus group’s demand curve for iTunes downloads. The estimated coefficient on price was - 413, and the t-statistic was -12.8. a. Using these values, what is the standard error of this estimated coefficient? b. Suppose we had another focus group sample, ran a regression on that sample, and obtained the same coefficient on price but with a standard error 10 times as large. What can you say about the statistical significance of the price coefficient in this second sample? *6.2. Using Excel or another program, estimate the linear OLS demand regression for the iTunes focus group data in the Managerial Solution. What is the R2? What are the coefficient estimates, the standard errors, and the t-statistics for each coefficient? Using a 95% confidence criterion, would you reject the hypothesis that the price coefficient is zero? (You can compare most of your answers to those in the Managerial Solution.) 7. Spreadsheet Exercises 7.1. The marketing department of Acme Inc. has estimated the following demand function for its popular carpet deodorizer, Freshbreeze: Q = 100 - 5p, where Q is the quantity of an 8-ounce box (sold in thousand units) and p the price of an 8-ounce box. Using Excel, calculate the point price elasticity of demand, ε, for price, p = 1, 2, 3, c , 19. Describe 83 the pattern of price elasticity of demand that you have calculated along the demand curve. 7.2. The ice cream store Cool Stuff sells exotic ice creams, including Tropical Cream and Green Mango. Cool Stuff has been varying the prices of these two flavors over the past 12 weeks and has recorded the sales data. The table shows the quantity sold of Tropical Cream, Q, given the price of a half-gallon of Tropical Cream, p, and the price of the other flavor, Green Mango, po. Use these data to estimate the demand function for Tropical Cream. Are the coefficients on the two prices statistically significantly different from zero at the 5% significance level? What is the R2? Q p po 84 8.5 5.25 82 9 6 85 8.75 6 83 9.25 6.5 82 9.5 6.25 84 9.25 6.25 87 8.25 5.25 81 10 7 82 10 7.25 79 10.5 7.25 82 9.5 6.75 78 10.25 7.25 Appendix 3 The Excel Regression Tool The Regression tool available in the Windows version of Microsoft Excel is easier to use than the LINEST function.24 We demonstrate its use in Excel 2010 for the Camry focus group example analyzed in Section 3.3. 1. As shown in the screenshot, enter the data in an Excel spreadsheet. 2. Click on the Data tab, then on the Data Analysis icon at the upper right of the spreadsheet.25 The Data Analysis dialog displays as shown. Select the Regression tool and click OK. 3. In the Regression dialog that displays, fill in the Input Y Range field (the dependent variable) by selecting cells A1 through A9 or by typing A1:A9 into the box. 4. Fill in the Input X Range field (the explanatory variables) by selecting the cells containing the prices or by typing B1:B9. 5. Select the Labels box. Click the Output Range button, enter A12 in the associated box, and then click OK. Excel displays the regression results. This regression output includes the R2, which is (approximately) 0.98. It also shows that the estimated regression line is Q = 53.86 - 1.438p. Based on the associated t-statistics, we conclude that the coefficients on the constant term (the intercept) and on p are statistically significant at the 0.05 level. 24The Mac version of Excel (from 2008 onward) has LINEST but does not have the Regression tool. However, similar tools are available from third parties for use with Excel, such as StatPlus, which is available free of charge at www.analystsoft.com/en/products/statplusmacle. 84 25If you do not see the Data Analysis icon, the Analysis Toolpak is not installed in your version of Excel. See Excel Help for installation instructions. Consumer Choice 4 If this is coffee, please bring me some tea; but if this is tea, please bring me some coffee. —Abraham Lincoln Managerial P roblem Paying Employees to Relocate When Google wants to transfer an employee from its Washington, D.C., office to its London branch, it has to decide how much compensation to offer the worker to move. International firms are increasingly relocating workers throughout their home countries and internationally. For example, KPMG, an international accounting and consulting firm, has a goal of having 25% to 30% of its professional staff gain international experience at some point. In 2010, about 5,000 of its 120,000 global employees were on foreign assignment. As you might expect, workers are not always enthusiastic about being relocated. In a survey by Runzheimer International, 79% of relocation managers responded that they confronted resistance from employees who were asked to relocate to high-cost locations. A survey of some of their employees found that 81% objected to moving because of fear of a lowered standard of living. One possible approach to enticing employees to relocate is for the firm to assess the goods and services consumed by employees in the original location and then pay those employees enough to allow them to consume essentially the same items in the new location. According to a survey by Mercer, 79% of international firms reported that they provided their workers with enough income abroad to maintain their home lifestyle. However, economists who advise on compensation packages point out that such an approach will typically overcompensate employees by paying them more than they need to obtain the same level of economic well-being they have in the original city. How can a firm’s human resources (HR) manager use consumer theory to optimally compensate employees who are transferred to other cities? E conomists use the theory of consumer choice to analyze consumers’ decisions and to derive demand curves. To answer questions about individual consumer choice (or any kind of individual decision making) we need a model of individual behavior. The standard economic model of consumer behavior is based on the following premises or assumptions. ◗ Individual tastes or preferences determine the pleasure or satisfaction people derive from the goods and services they consume. 85 86 CHAPTER 4 Consumer Choice ◗ Consumers face constraints or limits on their choices, particularly because their budgets limit how much they can buy. ◗ Consumers seek to maximize the level of satisfaction they obtain from consumption, subject to the constraints they face. People seek to “do the best with what they have.” Consumers spend their money on the bundles of products that give them the most pleasure or satisfaction. Someone who likes music and does not have much of a sweet tooth might spend a lot of money on concerts and relatively little on sweet desserts. By contrast, a consumer who loves chocolate and has little interest in music might spend a significant amount on gourmet chocolate and never go to a concert. Consumers must make choices about which goods to buy. Limits on the amount they can spend (called “budget constraints”) prevent them from buying everything that catches their fancy. Other constraints such as legal restrictions on items such as alcohol and recreational drugs may also restrain their choices. Therefore, consumers buy the bundles of goods they like best subject to their budget constraints and subject to legal or other relevant constraints. In economic analysis designed to explain behavior, economists assume that the consumer is the boss (sometimes referred to as consumer sovereignty). If Jason gets pleasure from smoking, an economist does not confuse the economic analysis of Jason’s choices by interjecting his or her own personal judgment that smoking is undesirable. Economists accept the consumer’s tastes and seek to predict the resulting behavior. Accepting each consumer’s tastes is not the same as condoning the resulting behaviors. An economist might reasonably believe that smoking should be avoided. However, if the economist wants to know whether Jason will smoke more next year if the price of cigarettes decreases by 10%, any prediction is unlikely to be correct if the economist says, “He should not smoke; therefore, we predict he will stop smoking next year.” A prediction based on Jason’s actual tastes is more likely to be correct: “Given that Jason likes cigarettes, he is likely to smoke more next year if the price of cigarettes falls.” Ma in Topics 1. Consumer Preferences: We use three properties of preferences to predict which combinations or bundles of goods an individual prefers to other combinations. In this chapter, we examine six main topics 2. Utility: We summarize a consumer’s preferences using a utility function, which assigns to each possible bundle of goods a numerical value, utility, that reflects the consumer’s relative ranking of these bundles. 3. The Budget Constraint: Prices and consumers’ limited budgets constrain how much they can buy and determine the rate at which a consumer can substitute one good for another. 4. Constrained Consumer Choice: Consumers maximize their utility from consuming various possible bundles of goods given their available budgets. 5. Deriving Demand Curves: We use consumer theory to derive demand curves and show how a change in price causes a movement along a demand curve. 6. Behavioral Economics: Experiments indicate that people sometimes deviate from rational, maximizing behavior. 4.1 Consumer Preferences 4.1 87 Consumer Preferences I have forced myself to contradict myself in order to avoid conforming to my own taste. —Marcel Duchamp, Dada artist We start our analysis of consumer behavior by examining consumer preferences. Once we know about consumers’ preferences, we will combine that knowledge with information about the constraints consumers face to answer many questions of interest, such as the managerial problem posed at the beginning of this chapter. A consumer faces choices involving many goods. Would ice cream or cake make a better dessert? Is it better to rent a large apartment or rent a single room and use the savings to pay for trips and concerts? In short, a consumer must allocate his or her available budget to buy a bundle (also called a market basket or combination) of goods. How do consumers choose the bundles of goods they buy? One possibility is that consumers behave randomly and blindly choose one good or another without any thought. However, consumers appear to make systematic choices. For example, most consumers buy very similar items each time they visit a grocery store. A consumer typically ignores most items and buys a few particular items repeatedly. A consumer who likes apple juice and dislikes orange juice repeatedly buys apple juice and rarely if ever buys orange juice. In contrast, a consumer who chose randomly would be as likely to buy apple juice as orange juice. By observing a consumer’s consistent purchase of apple juice rather than orange juice, we can reject the hypothesis of random choices. To explain consumer behavior, economists assume that consumers have a set of tastes or preferences that they use to guide them in choosing between goods. These tastes differ substantially among individuals. For example, three out of four European men prefer colored underwear, while three out of four American men prefer white underwear.1 Let’s start by specifying the underlying assumptions in the economist’s model of consumer behavior. Properties of Consumer Preferences Do not do unto others as you would that they should do unto you. Their tastes may not be the same. —George Bernard Shaw Economists make three critical assumptions about the properties of consumers’ preferences. For brevity, these properties are referred to as completeness, transitivity, and more is better (or, alternatively, as nonsatiation). Completeness. The completeness property holds that, when facing a choice between any two bundles of goods, a consumer can rank them so that one and only one of the following three relationships is true. 1. The consumer prefers the first bundle to the second. 2. The consumer prefers the second bundle to the first. 3. The consumer likes the two bundles equally and therefore is indifferent between the two bundles. 1L. M. Boyd, “The Grab Bag,” San Francisco Examiner, September 11, 1994, p. 5. 88 CHAPTER 4 Consumer Choice This property rules out the possibility that the consumer cannot decide on his or her preferences. Indifference is allowed, but indecision is not. Transitivity. We assume that preferences are transitive. More specifically, we say that if a consumer weakly prefers Bundle a to Bundle b—likes a at least as much as b—and weakly prefers Bundle b to Bundle c, the consumer also weakly prefers Bundle a to Bundle c. Transitivity of weak preference implies that indifference is also transitive: If a consumer is indifferent between Bundle a and Bundle b, and is indifferent between Bundle b and Bundle c, then the consumer must also be indifferent between Bundle a and Bundle c. Strict preference must also be transitive: If a is strictly preferred to b and b is strictly preferred to c, it follows that a must be strictly preferred to c. Also, if a is preferred to b and the consumer is indifferent between b and c, then the consumer must also prefer a to c. Transitivity is a necessary condition for what most people view as rational behavior. Suppose Amy told you she would prefer a scoop of ice cream to a piece of cake but would prefer a piece of cake to a chocolate bar, and then added that she would prefer a chocolate bar to a scoop of ice cream. She might reasonably be accused of being irrational or inconsistent. At the very least, it would be difficult to know which dessert to serve her. More Is Better. The more-is-better property holds that, all else being the same, more of a good is better than less. This property is really just a statement of what we mean by a good: a commodity for which more is preferred to less, at least at some levels of consumption. In contrast, a bad is something for which less is preferred to more, as with pollution (which we study in Chapter 16). Because managers primarily care about goods, we will concentrate on them. The more-is-better property is not essential for the following analysis of consumer preferences—our most important results would hold even without this property. These results would, if properly interpreted, apply to bads and to items about which we do not care about one way or the other, as well as for goods. However, the moreis-better assumption greatly simplifies the analysis. M ini-Case You Can’t Have Too Much Money Not surprisingly, studies based on data from many nations find that richer people are happier on average than poorer people (Helliwell et al., 2012). But, do people become satiated? Can people be so rich that they can buy everything they want and additional income does not increase their feelings of well-being? Using recent data from many countries, Stevenson and Wolfers (2008) found no evidence of a satiation point beyond which wealthier countries or wealthier individuals have no further increases in subjective well-being. Moreover, they found a clear positive relationship between average levels of self-reported feelings of happiness or satisfaction and income per capita within and across countries. Less scientific, but perhaps more compelling, is a survey of wealthy U.S. citizens who were asked, “How much wealth do you need to live comfortably?” On average, those with a net worth of over $1 million said that they needed $2.4 million to live comfortably, those with at least $5 million in net worth said that they need $10.4 million, and those with at least $10 million wanted $18.1 million. Apparently, most people never have enough. 4.1 Consumer Preferences 89 Preference Maps Surprisingly, with just these three properties, we can say a lot about consumer preferences. One of the simplest ways to summarize information about a consumer’s preferences is to create a graphical interpretation—sometimes called a preference map. For graphical simplicity, we concentrate on choices between only two goods, but the model can be generalized algebraically to handle any number of goods. Each semester, Lisa, who lives for fast food, decides how many pizzas and burritos to eat. The various bundles of pizzas and burritos she might consume are shown in panel a of Figure 4.1, with (individual-size) pizzas per semester on the horizontal axis and burritos per semester on the vertical axis. F IG U RE 4. 1 Bundles of Pizzas and Burritos That Lisa Might Consume Pizzas per semester are on the horizontal axis, and burritos per semester are on the vertical axis. (a) Lisa prefers more to less, so she prefers Bundle e to any bundle in area B, including d. Similarly, she prefers any bundle in area A, including f, to e. (b) The indifference curve, (b) 25 C B, Burritos per semester B, Burritos per semester (a) A c f 20 15 e a d 10 15 25 30 Z, Pizzas per semester (c) c f 20 I3 e 15 10 c f 20 e 15 a d b I1 D B 25 25 10 b 5 B, Burritos per semester I1, shows a set of bundles (including c, e, and a) among which she is indifferent: She likes all three bundles on this curve equally. (c) The three indifference curves, I1, I2, and I3, are part of Lisa’s preference map, which summarizes her preferences. d I2 I1 15 25 30 Z, Pizzas per semester 15 25 30 Z, Pizzas per semester 90 CHAPTER 4 Consumer Choice At Bundle e, for example, Lisa consumes 25 pizzas and 15 burritos per semester. By the more-is-better property, Lisa prefers all the bundles that lie above and to the right (area A) to Bundle e because they contain at least as much or more of both pizzas and burritos as Bundle e. Thus, she prefers Bundle f (30 pizzas and 20 burritos) in that region. By using the more-is-better property, we know that Lisa prefers e to all the bundles that lie in area B, below and to the left of e, such as Bundle d (15 pizzas and 10 burritos). All the bundles in area B contain fewer pizzas or fewer burritos or fewer of both than does Bundle e. From panel a, we do not know whether Lisa prefers Bundle e to bundles such as b (30 pizzas and 10 burritos) in area D, which is the region below and to the right of e, or c (15 pizzas and 25 burritos) in area C, which is the region above and to the left of Bundle e. We can’t use the more-is-better property to determine which bundle is preferred because each of these bundles contains more of one good and less of the other than e does. To be able to state with certainty whether Lisa prefers particular bundles in areas C or D to Bundle e, we have to know more about her tastes for pizza and burritos. Preferences and Indifference Curves. Suppose we asked Lisa to identify all the bundles that give her the same amount of pleasure she gets from consuming Bundle e. In panel b of Figure 4.1, we use her answers to draw curve I 1 through all bundles she likes as much as she likes e. Curve I 1 is an indifference curve: the set of all bundles of goods that a consumer views as being equally desirable. Indifference curve I 1 includes Bundles c, e, and a, so Lisa is indifferent about consuming Bundles c, e, and a. From this indifference curve, we also know that Lisa prefers e (25 pizzas and 15 burritos) to b (30 pizzas and 10 burritos). How do we know that? Bundle b lies below and to the left of Bundle a, so Bundle a is preferred to Bundle b by the more-is-better property. Both Bundle a and Bundle e are on indifference curve I 1, so Lisa likes Bundle e as much as Bundle a. Because Lisa is indifferent between e and a and she prefers a to b, she must prefer e to b by transitivity. If we asked Lisa many, many questions, we could, in principle, draw an entire set of indifference curves through every possible bundle of burritos and pizzas. Lisa’s preferences are summarized in an indifference map or preference map, which is a complete set of indifference curves that summarize a consumer’s tastes. It is referred to as a map because it uses the same principle as a topographical or contour map, in which each line shows all points with the same height or elevation. With an indifference map, each line shows points (combinations of goods) with the same utility or well-being. Panel c of Figure 4.1 shows three of Lisa’s indifference curves: I 1, I 2, and I 3. In this figure, the indifference curves are parallel, but they need not be. We can demonstrate that all indifference curve maps must have the following four properties. 1. Bundles on indifference curves farther from the origin are preferred to those on indifference curves closer to the origin. 2. An indifference curve goes through every possible bundle. 3. Indifference curves cannot cross. 4. Indifference curves slope downward. First, we show that bundles on indifference curves farther from the origin are preferred to those on indifference curves closer to the origin. By the more-is-better property, Lisa prefers Bundle f to Bundle e in panel c of Figure 4.1. She is indifferent among all the bundles on indifference curve I 3 and Bundle f, just as she is indifferent 4.1 Consumer Preferences 91 among all the bundles, such as Bundle c, on indifference curve I 2, and Bundle e. By the move-is-better property, she prefers Bundle f to Bundle e, which she likes as much as Bundle c, so she also prefers Bundle f to Bundle c. By this type of reasoning, she prefers all bundles on I 3 to all bundles on I 2. Second, we show that an indifference curve goes through every possible bundle. This property is a consequence of the completeness assumption: The consumer can compare any bundle to another. Compared to a given bundle, some bundles are preferred to it, some are enjoyed equally, and some are inferior to it. Connecting the bundles that give the same well-being produces an indifference curve that includes the given bundle. Third, we show that indifference curves cannot cross. If two indifference curves did cross, the bundle at the point of intersection would be on both indifference curves. But a given bundle cannot be on two indifference curves. Suppose that two indifference curves crossed at Bundle e as in panel a of Figure 4.2. Because Bundles e and a lie on the same indifference curve I 1, Lisa is indifferent between e and a. Similarly, she is indifferent between e and b because both are on I 2. By transitivity, if Lisa is indifferent between e and a and she is indifferent between e and b, she must be indifferent between a and b. But that’s impossible! Bundle b is above and to the right of bundle a, which means it contains more of both goods. Thus, Lisa must prefer b to a by the more-is-better property. Because preferences are transitive and consumers prefer more to less, indifference curves cannot cross. Finally, we show that indifference curves must be downward sloping. Suppose to the contrary that an indifference curve sloped upward, as in panel b of Figure 4.2. The consumer is indifferent between Bundles a and b because both lie on the same indifference curve, I. But the consumer must prefer b to a by the more-is-better property: Bundle a lies below and to the left of Bundle b. Because of this contradiction—the consumer cannot both be indifferent between a and b and strictly prefer b to a— indifference curves cannot be upward sloping. For example, if Lisa views pizza and burritos as goods, she cannot be indifferent between a bundle of one pizza and one burrito and another bundle with two of each. (a) Crossing (b) Upward Sloping B, Burritos per semester (a) Suppose that the indifference curves cross at Bundle e. Lisa is indifferent between e and a on indifference curve I1 and between e and b on I2. If Lisa is indifferent between e and a and she is indifferent between e and b, she must be indifferent between a and b by transitivity. But b has more of both pizzas and burritos than a, so she must prefer a to b. Because of this contradiction, indifference curves cannot cross. (b) Suppose that indifference curve I slopes upward. The consumer is indifferent between b and a because they lie on I but prefers b to a by the more-is-better assumption. Because of this contradiction, indifference curves cannot be upward sloping. B, Burritos per semester F IG U RE 4. 2 Impossible Indifference Curves b a e b a I2 I I1 Z, Pizzas per semester Z, Pizzas per semester 92 CHAPTER 4 Consumer Choice Willingness to Substitute Between Goods. Lisa is willing to make some trade-offs between goods. The downward slope of her indifference curves shows that Lisa is willing to give up some burritos for more pizza or vice versa. She is indifferent between Bundles a and b on her indifference curve I in panel a of Figure 4.3. If she initially has Bundle a (eight burritos and three pizzas), she could get to Bundle b (five burritos and four pizzas) by trading three burritos for one more pizza. She is indifferent as to whether she makes this trade or not. Lisa’s willingness to trade one good for another is measured by her marginal rate of substitution (MRS). The MRS shows the rate at which a consumer can substitute one good for another while remaining on the same indifference curve. Graphically, the MRS is the slope of the indifference curve.2 If pizza is on the horizontal axis, Lisa’s marginal rate of substitution of burritos for pizza is ΔB MRS = ΔZ where ΔB is the number of burritos Lisa will give up to get ΔZ more pizzas while staying on the same indifference curve. Roughly speaking, we can say that the MRS is the amount of one good a consumer will sacrifice to obtain one more unit of F IG U RE 4. 3 Marginal Rate of Substitution (a) Indifference Curve Convex to the Origin (b) Indifference Curve Concave to the Origin B, Burritos per semester more burritos to get one more pizza, the fewer the burritos she has. Moving from Bundle c to b, she will trade one pizza for three burritos, whereas moving from b to a, she will trade one pizza for two burritos, even though she now has relatively more burritos to pizzas. B, Burritos per semester (a) At Bundle a, Lisa is willing to give up three burritos for one more pizza; at b, she is willing to give up only two burritos to obtain another pizza. That is, the relatively more burritos she has, the more she is willing to trade for another pizza. (b) An indifference curve of this shape is unlikely to be observed. Lisa would be willing to give up a 8 –3 5 b 1 –2 1 –1 2 0 4 2The 5 b 1 –3 d 1 3 –2 5 c 3 a 7 c 2 1 I 6 Z, Pizzas per semester I 0 3 4 5 6 Z, Pizzas per semester slope of a straight line is “the rise over the run”: how much we move along the vertical axis (rise) as we move along the horizontal axis (run). The slope of an indifference curve at a point is the limit of the rise over the run as the change along the horizontal axis (the “run”) gets very small. The slope of an indifference curve at a particular point is the same as the slope of a straight line that is tangent to the indifference curve at that point. 4.1 Consumer Preferences 93 another good while staying on the same indifference curve. If ΔZ is 1, then the associated value of ΔB is the MRS. Thus if Lisa is willing to give up 3 burritos (ΔB = -3) to get 1 more pizza (ΔZ = 1), then the MRS is - 31 = -3. We can illustrate why the MRS is negative by moving from Bundle a to Bundle b in panel a of Figure 4.3. The negative sign shows that Lisa is willing to give up some of one good to get more of the other: Her indifference curve slopes downward. In specifying the MRS, we must be clear about which good is on the horizontal axis. Because pizza is on the horizontal axis in our figure, the MRS of “burritos for pizza” is -3, which is the slope of the indifference curve. If we were to switch axes so that burritos were on the horizontal axis, we could calculate the MRS of “pizza for burritos,” which We are out of tickets for Swan Lake. measures how much pizza Lisa would give up to Do you want tickets for Wrestlemania? get one more burrito while staying on the same indifference curve. In this case, the MRS of pizza for burritos would be ΔZ/ΔB, which is - 13 . From Lisa’s point of view, one pizza is worth 3 burritos (the MRS of burritos for pizza is -3) or, equivalently, 1 burrito is worth about 13 of a pizza (the MRS of pizza for burritos is - 13 ). Curvature of Indifference Curves. The indifference curves we have used so far, such as I in panel a of Figure 4.3, are convex to the origin of the graph: That is, the indifference curves are “bowed in” toward the origin. Because the indifference curve in panel a is convex, when Lisa has a large amount of burritos, B, she is willing to give up more of that good to get one more pizza, Z, than she would if she had only a small number of burritos. Starting at point a in panel a of Figure 4.3, Lisa is willing to give up three burritos to obtain one more pizza. At b, she is willing to trade only two burritos for a pizza. At c, she is even less willing to trade; she will give up only one burrito for another pizza. This willingness to trade fewer burritos for one more pizza as we move down and to the right along the indifference curve reflects a diminishing marginal rate of substitution. An indifference curve doesn’t have to be convex, but casual observation suggests that most people’s indifference curves over most pairs of products are convex. It is unlikely, for example, that Lisa’s indifference curves would be concave, as in panel b of Figure 4.3. If her indifference curve were concave, Lisa would be willing to give up more burritos to get one more pizza when she has fewer burritos. In panel b, she trades one pizza for three burritos moving from Bundle c to b, and she trades one pizza for only two burritos moving from b to a, even though her ratio of burritos to pizza is greater. Two extreme types of indifference curves are plausible: straight-line indifference curves and right-angle indifference curves. Straight-line indifference curves reflect perfect substitutes, which are goods that are essentially equivalent from the consumer’s point of view. The consumer is completely indifferent between the two goods. For example, if Bill cannot taste any difference between Coca-Cola and Pepsi-Cola, he views them as perfect substitutes: He is indifferent between one CHAPTER 4 94 Consumer Choice F IG U RE 4. 4 Perfect Substitutes, Perfect Complements, Imperfect Substitutes (b) Perfect Complements 4 3 2 1 I1 0 1 I2 I3 I4 2 3 4 Pepsi, Cans per week c e 3 d 2 a 1 (c) Imperfect Substitutes b I3 I2 I1 B, Burritos per semester (a) Perfect Substitutes Ice cream, Scoops per week She will not substitute between the two; she consumes them only in equal quantities. (c) Lisa views burritos and pizza as imperfect substitutes. Her indifference curve lies between the extreme cases of perfect substitutes and perfect complements. Coke, Cans per week (a) Bill views Coke and Pepsi as perfect substitutes. His indifference curves are straight, parallel lines with a marginal rate of substitution (slope) of -1. Bill is willing to exchange one can of Coke for one can of Pepsi. (b) Cathy likes pie à la mode but does not like pie or ice cream by itself: She views ice cream and pie as perfect complements. I 0 1 2 3 Pie, Slices per week Z, Pizzas per semester additional can of Coke and one additional can of Pepsi. His indifference curves for these two goods are straight, parallel lines with a slope of -1 everywhere along the curve, as in panel a of Figure 4.4. Thus, Bill’s marginal rate of substitution is -1 at every point along these indifference curves. The slope of indifference curves of perfect substitutes need not always be -1; it can be any constant rate. For example, Helen knows from reading the labels that Clorox bleach is twice as strong as a generic brand, but otherwise no different. As a result, she is indifferent between one cup of Clorox and two cups of the generic bleach. If the generic bleach is on the vertical axis, the slope of her indifference curve is -2.3 The other extreme case is perfect complements: goods that an individual wants to consume only in fixed proportions. Cathy doesn’t like pie by itself or vanilla ice cream by itself, but she loves pie à la mode (a slice of pie with a scoop of vanilla ice cream on top). Her indifference curves have right angles in panel b of Figure 4.4. Bundle a consists of one piece of pie and one scoop of ice cream, combining to make one serving of pie à la mode. If she gets an additional scoop of ice cream but no pie to go with it (Bundle d) she remains on the same indifference curve: the extra scoop of ice cream by itself provides no additional benefit to Cathy. Adding a third scoop of ice cream (shown as Bundle e) is also a matter of indifference to Cathy. She gets no extra benefit and remains on the same indifference curve. Similarly, if Cathy has only one scoop of ice cream, additional pieces of pie beyond the first leave her on the same indifference curve. With preferences like this, Cathy consumes only bundles like a, b, and c, in which pie and ice cream are in equal proportions. She would never want to pay for any additional ice cream that was not matched by a piece of pie, and she would never 3Sometimes it is difficult to guess which goods are close substitutes. According to Harper’s Index 1994, flowers, perfume, and fire extinguishers rank 1, 2, and 3 among “appropriate” Mother’s Day gifts. Few would guess that perfume and fire extinguishers are substitutes. 4.2 Utility 95 want to pay for a piece of pie without a scoop of ice cream to go with it. She will only consume ice cream and pie in equal proportions. With a bundle like a, b, or c, she will not substitute a piece of pie for an extra scoop of ice cream. For example, if she were at b, she would be unwilling to give up an extra slice of pie to get, say, two extra scoops of ice cream, as at point e. Indeed, she wouldn’t give up the slice of pie even for a virtually unlimited amount of extra ice cream because the extra ice cream is worthless to her. The standard-shaped, convex indifference curve in panel c of Figure 4.4 lies between these two extreme examples. Convex indifference curves show that a consumer views two goods as imperfect substitutes. 4.2 Utility Underlying our model of consumer behavior is the belief that consumers can compare various bundles of goods and decide which gives them the greatest pleasure or satisfaction. It is possible to summarize a consumer’s preferences by assigning a numerical value to each possible bundle to reflect the consumer’s relative ranking of these bundles. Following Jeremy Bentham, John Stuart Mill, and other nineteenth-century British economist-philosophers, economists apply the term utility to this set of numerical values that reflect the relative rankings of various bundles of goods. The statement that “Lorna prefers Bundle x to Bundle y” is equivalent to the statement that “consuming Bundle x gives Lorna more utility than consuming Bundle y.” For example, Lorna prefers x to y if Bundle x gives Lorna a utility level of 10 and Bundle y gives her a utility level of 8. Utility Functions If we knew the utility function—the relationship between utility measures and every possible bundle of goods—we could summarize the information in indifference maps succinctly. Lisa’s utility function, U(B, Z), tells us how much utility she gets from B burritos and Z pizzas. Given that her utility function reflects her preferences, if Lisa prefers Bundle 1, (B1, Z1), to Bundle 2, (B2, Z2), then the utility she gets from the first bundle exceeds that from the second bundle: U(B1, Z1) 7 U(B2, Z2). For example, suppose that the utility, U, that Lisa gets from burritos and pizzas is U = 2BZ. From this function, we know that the more she consumes of either good, the greater the utility she receives. Using this function, we can determine whether Lisa would be happier if she had Bundle x with 9 burritos and 16 pizzas or Bundle y with 13 of each. The utility she gets from x is 12( = 29 * 16). The utility she gets from y is 13(= 213 * 13). Therefore, she prefers y to x. The utility function is a concept that economists use to help them think about consumer behavior; utility functions do not exist in any fundamental sense. If you asked your mother what her utility function is, she would be puzzled—unless, of course, she is an economist. But if you asked her enough questions about choices of bundles of goods, you could construct a function that accurately summarizes her preferences. For example, by questioning people, Rousseas and Hart (1951) constructed indifference curves between eggs and bacon, and MacCrimmon and Toda 96 CHAPTER 4 Consumer Choice (1969) constructed indifference curves between French pastries and money (which can be used to buy all other goods). Typically, consumers can easily answer questions about whether they prefer one bundle to another, such as “Do you prefer a bundle with one scoop of ice cream and two pieces of cake to another bundle with two scoops of ice cream and one piece of cake?” But they have difficulty answering questions about how much more they prefer one bundle to another because they don’t have a measure to describe how their pleasure from two goods or bundles differs. Therefore, we may know a consumer’s rank-ordering of bundles even if we do not have a good idea of how much that consumer prefers one bundle to another. Ordinal and Cardinal Utility The term ordinal is used to describe a measure that contains information only about rankings or orderings. For example, a movie critic might give a movie between one and four stars. However, a 4-star movie is not necessarily “twice as good” as a 2-star movie or four times as good as a 1-star movie. All we can say is that the critic likes the 4-star movie better than the 2-star movie, which in turn is preferred to the 1-star movie: We really know only the critic’s relative rankings. Thus, movie rankings are an ordinal measure, even though numbers (the number of stars) might be used to represent the rankings. With utility, if we know only a consumer’s relative rankings of bundles, our measure of utility is ordinal. A cardinal measure is based on absolute numerical comparisons, as with length or weight. Cardinal measures contain more information than ordinal measures. For example, money is a cardinal measure. If Sofia has $100 and Hu has $50, we know not only that Sofia has more money than Hu (an ordinal comparison), but that she has precisely twice as much as Hu (a cardinal comparison). Economists sometimes treat utility as a cardinal measure, allowing for statements like “Bundle A is twice as good as Bundle B,” instead of just saying that Bundle A is preferred to Bundle B. Most of our discussion of consumer choice in this chapter holds if utility has only ordinal properties. If utility is an ordinal measure, we should not put any weight on the absolute difference between the utility associated with one bundle and another. We care only about the relative utility or ranking of the two bundles. Marginal Utility Using Lisa’s utility function over burritos and pizza, we can show how her utility changes if she gets to consume more of one of the goods. Suppose that Lisa has the utility function in Figure 4.5. The curve in panel a shows how Lisa’s utility rises as she consumes more pizzas while we hold her consumption of burritos fixed at 10. Because pizza is a good, Lisa’s utility rises as she consumes more pizza. If her consumption of pizzas increases from Z = 4 to 5, ΔZ = 5 - 4 = 1, and her utility increases from U = 230 to 250, ΔU = 250 - 230 = 20. The extra utility (ΔU) that she gets from consuming one more unit of a good (ΔZ = 1) is the marginal utility from that good. Thus, marginal utility is the slope of the utility function as we hold the quantity of the other good constant. MUZ = ΔU . ΔZ 4.2 Utility 97 F IG U RE 4. 5 Utility and Marginal Utility (a) Utility U, Utils As Lisa consumes more pizza, holding her consumption of burritos constant at 10, her total utility, U, increases and her marginal utility of pizza, MUZ, decreases (though it remains positive). (a) If she increases her consumption of pizza from 4 to 5 per semester while holding her consumption of burritos fixed at 10, her utility increases from 230 to 250. Her marginal utility is the extra utility she gets, ΔU = 250 - 230 = 20 from an extra pizza, ΔZ = 1, which is MUZ = ΔU/ΔZ = 20/1 = 20. (b) At Z = 5, the height of Lisa’s marginal utility curve is 20. Utility function, U (10, Z ) 350 250 230 0 ΔZ = 1 1 2 3 4 ΔU = 20 5 6 MUZ , Marginal utility of pizza (b) Marginal Utility 7 8 9 10 Z, Pizzas per semester 130 Marginal utility of pizza, MUZ 20 0 1 2 3 4 5 6 7 8 9 10 Z, Pizzas per semester Lisa’s marginal utility from increasing her consumption of pizza from 4 to 5 is MUZ = ΔU 20 = = 20. ΔZ 1 Panel b in Figure 4.5 shows that Lisa’s marginal utility from consuming one more pizza varies with the number of pizzas she consumes, holding her consumption of burritos constant. Her marginal utility of pizza curve falls as her consumption of pizza increases, but the marginal utility remains positive: Each extra pizza gives Lisa pleasure, but it gives her less pleasure relative to other goods than did the previous pizza. Using Calculus Marginal Utility The marginal utility from a particular good is the partial derivative of the utility function with respect to that good, which measures how utility changes as we change one good while holding consumption of other goods constant. Thus, if Lisa’s utility function is U(B, Z), her marginal utility from Z is the partial derivative of U with respect to Z: MUZ = 0U(B, Z)/0Z. 98 CHAPTER 4 Consumer Choice Marginal Rates of Substitution Earlier we learned that the marginal rate of substitution (MRS) is the slope of the indifference curve. The marginal rate of substitution can also be expressed using marginal utilities. If Lisa has 10 burritos and 4 pizzas in a semester and gets one more pizza, her utility rises. That extra utility is the marginal utility from the last pizza, MUZ. Similarly, if she receives one extra burrito instead, her marginal utility from the last burrito is MUB. Suppose that Lisa trades from one bundle on an indifference curve to another by giving up some burritos to gain more pizza. She gains marginal utility from the extra pizza but loses marginal utility from fewer burritos. We can show that the marginal rate of substitution can be written in terms of the marginal utilities: MRS = MUZ ΔB . = ΔZ MUB (4.1) Equation 4.1 tells us that the MRS, which is the slope of the indifference curve at a particular bundle, depends on the negative of the ratio of the marginal utility of pizza to the marginal utility of burritos. (We derive Equation 4.1 using calculus in Appendix 4A.) An example illustrates the logic underlying Equation 4.1. Suppose that Lisa gains one unit of utility (one util) if she eats one more burrito, MUB = 1, and two utils if she has one more pizza, MUZ = 2. That is, one more pizza gives her as much extra pleasure as two burritos. Thus, her utility stays the same—she stays on the same indifference curve—if she exchanges two burritos for one pizza, so her MRS = -MUZ/MUB = -2. 4.3 The Budget Constraint Knowing an individual’s preferences is only the first step in analyzing that person’s consumption behavior. Consumers maximize their well-being subject to constraints. The most important constraint most of us face in deciding what to consume is our personal budget constraint. If we cannot save and borrow, our budget is the income we receive in a given period. If we can save and borrow, we can save money early in life to consume later, such as when we retire, or we can borrow money when we are young and repay those sums later in life. Savings are, in effect, a good that consumers can buy. For simplicity, we assume that each consumer has a fixed amount of money to spend now, so we can use the terms budget and income interchangeably. For graphical simplicity, we assume that consumers spend their money on only two goods. If Lisa spends all her budget, Y, on pizza and burritos, then her budget constraint is pBB + pZZ = Y, (4.2) where pBB is the amount she spends on burritos and pZZ is the amount she spends on pizzas. Equation 4.2 shows that her expenditures on burritos and pizza use up her entire budget. 4.3 The Budget Constraint 99 How many burritos can Lisa buy? Subtracting pZZ from both sides of Equation 4.2 and dividing both sides by pB, we determine the number of burritos she can purchase to be B = pZ Y Z. pB pB (4.3) According to Equation 4.3, Lisa can afford to buy more burritos only if ◗ her income (Y) increases, ◗ the price of burritos (pB) or pizza (pZ) falls, or ◗ she purchases fewer pizzas (Z). For example, if Lisa has one more dollar of income (Y), she can buy 1/pB more burritos. If pZ = $1, pB = $2, and Y = $50, Equation 4.3 is B = $1 $50 Z = 25 - 12 Z. $2 $2 (4.4) As Equation 4.4 shows, every two pizzas cost Lisa one burrito. How many burritos can she buy if she spends all her money on burritos? She can buy 25 burritos: By setting Z = 0 in Equation 4.3, we find that B = Y/pB = $50/$2 = 25. Similarly, if she spends all her money on pizza, she can buy 50 of them: Setting B = 0, we can solve for Z = Y/pZ = $50/$1 = 50. Instead of spending all her money on pizza or all on burritos, she can buy some of each. Table 4.1 shows four possible bundles she could buy. For example, she can buy 20 burritos and 10 pizzas with $50. Equation 4.4 is plotted in Figure 4.6. This line is called a budget line or budget constraint: the bundles of goods that can be bought if the entire budget is spent on those goods at given prices. This budget line shows the combinations of burritos and pizzas that Lisa can buy if she spends all of her $50 on these two goods. The four bundles in Table 4.1 are labeled on this line. Lisa could, of course, buy any bundle that cost less than $50. The opportunity set is all the bundles a consumer can buy, including all the bundles inside the budget constraint and on the budget constraint (all those bundles of positive Z and B such that pBB + pZZ … Y). Lisa’s opportunity set is the shaded area in Figure 4.6. She could buy 10 burritos and 15 pieces of pizza for $35, which falls inside the constraint. Unless she wants to spend the other $15 on some other good, though, she might as T A BLE 4 .1 Allocations of a $50 Budget Between Burritos and Pizza Bundle Burritos, $2 each Pizza, $1 each a 25 0 b 20 10 c 10 30 d 0 50 100 CHAPTER 4 Consumer Choice If Y = $50, pZ = $1, and pB = $2, Lisa can buy any bundle in the opportunity set, the shaded area, including points on the budget line, L1, B = Y/pB - (pZ /pB) Z = $50/$2- ($1/$2)Z. If Lisa buys one more unit of Z, she must reduce her consumption of B by - (pZ /pB) = - 12 to stay within her budget. Thus, the slope, ΔB/ΔZ, of her budget line, which is also called the marginal rate of transformation (MRT ), is - (pZ /pB) = - 12. B, Burritos per semester F IG U RE 4. 6 Budget Line 25 = Y/pB 20 a b c 10 Budget line, L1 Opportunity set d 0 10 30 50 = Y/pZ Z, Pizzas per semester well spend all of it on the food she loves and pick a bundle on the budget constraint rather than inside it.4 Slope of the Budget Line The slope of the budget line is determined by the relative prices of the two goods. According to the budget line, Equation 4.3, B = Y/pB - (pZ/pB)Z, so every extra unit of Z that Lisa purchases reduces B by -pZ/pB. That is, the slope of the budget line is ΔB/ΔZ = -pZ/pB. Thus, the slope of the budget line depends on only the relative prices. Lisa faces prices of pZ = $1 and pB = $2, so the slope of her budget line is -pZ/pB = -$1/$2 = - 12. For example, if we reduce the number of pizzas from 10 at point b in Figure 4.6 to 0 at point a, the number of burritos that Lisa can buy rises from 20 at point b to 25 at point a, so ΔB/ΔZ = (25 - 20)/(0 - 10) = 5/(-10) = - 12. The slope of the budget line is called the marginal rate of transformation (MRT): the trade-off the market imposes on the consumer in terms of the amount of one good the consumer must give up to purchase more of the other good: MRT = pZ ΔB = - . pB ΔZ (4.5) Because Lisa’s MRT = - 12, she can “trade” an extra pizza for half a burrito or, equivalently, she has to give up two pizzas to obtain an extra burrito. 4The budget line in Figure 4.6 is a smooth, continuous line, which implies that Lisa can buy fractional numbers of burritos and pizzas. Is that true? Will a restaurant sell you a half of a burrito? Maybe not. Why then don’t we draw the budget line and opportunity set as discrete points (bundles) of whole numbers of burritos and pizzas instead of a continuous line? One reason is that Lisa can buy a burrito at a rate of one-half per time period. If Lisa buys one burrito every other week, she buys an average of one-half burrito every week. Thus, it is plausible that she could purchase fractional amounts over a particular time period. 4.3 The Budget Constraint Using Calculus The Marginal Rate of Transformation 101 By differentiating the budget constraint, Equation 4.3, B = Y/pB - (pZ/pB)Z, with respect to Z, we confirm that the slope of the budget constraint, or marginal rate of transformation, is MRT = dB/dZ = -pZ/pB, as in Equation 4.5. Effects of a Change in Price on the Opportunity Set If the price of pizza doubles but the price of burritos remains unchanged, the budget line swings in toward the origin in panel a of Figure 4.7. If Lisa spends all her money on burritos, she can buy as many burritos as before, so the budget line still hits the burrito axis at 25. If she spends all her money on pizza, however, she can now buy only half as many pizzas as before, so the budget line intercepts the pizza axis at 25 instead of at 50. The new budget line is steeper and lies inside the original one. As the price of pizza increases, the slope of the budget line, MRT, changes. The original line, L1, at the original prices, MRT = - 12, shows that Lisa could trade half a burrito for one pizza or two pizzas for one burrito. The new line, L2, MRT = pZ/pB = -$2/$2 = -1, indicates that she can now trade one burrito for one pizza, due to the increase in the price of pizza. Unless Lisa only wants to eat burritos, she is unambiguously worse off due to this increase in the price of pizza because she can no longer afford the combinations of pizza and burritos in the shaded “Loss” area. A decrease in the price of pizza would have the opposite effect: The budget line would rotate outward, pivoting around the intercept on the burrito axis. As a result, Lisa’s opportunity set would increase. F IG U RE 4. 7 Changes in the Budget Line (a) Price of Pizza Doubles (b) Income Doubles B, Burritos per semester burritos that Lisa can no longer afford. (b) If Lisa’s budget doubles from $50 to $100 and prices don’t change, her new budget line moves from L1 to L3. This shift is parallel: Both budget lines have the same slope or MRT of - 12. The new opportunity set is larger by the shaded area. B, Burritos per semester (a) If the price of pizza increases from $1 to $2 a slice, Lisa’s budget line rotates from L1 to L2 around the intercept on the burrito axis. The slope or MRT of the original budget line, L1, is - 12, while the MRT of the new budget line L2 is - 1. The shaded area shows the combinations of pizza and 25 L1 (pZ = $1) pZ doubles L2 50 25 Income doubles (pZ = $2) L1 (Y = $50) Loss 0 L3 (Y = $100) 50 25 Z, Pizzas per semester 0 Gain 100 50 Z, Pizzas per semester 102 CHAPTER 4 Consumer Choice Effects of a Change in Income on the Opportunity Set If the consumer’s income increases, the consumer can buy more of all goods. Suppose that Lisa’s income increases by $50 per semester to Y = $100. Her budget line shifts outward—away from the origin—and is parallel to the original constraint in panel b of Figure 4.7. Why is the new constraint parallel to the original one? The intercept of the budget line on the burrito axis is Y/pB, and the intercept on the pizza axis is Y/pZ. Thus, holding prices constant, the intercepts shift outward in proportion to the change in income. Originally, if she spent all her money on pizza, Lisa could buy 50 = $50/$1 pizzas; now she can buy 100 = $100/$1. Similarly, the burrito axis intercept goes from 25 = $50/$2 to 50 = $100/$2. Initially, if she consumed 25 burritos, Lisa could not consume any pizza; now if she consumes 25 burritos she can also consume 50 pizzas. A change in income affects only the position and not the slope of the budget line, because the slope is determined solely by the relative prices of pizza and burritos. A decrease in the prices of both pizzas and burritos in the same proportion has the same effect as an increase in income, as the next Q&A shows. Q&A 4.1 Is Lisa better off if her income doubles or if the prices of both the goods she buys fall by half? Answer Show that Lisa’s budget line and her opportunity set are the same with either change. As panel b of Figure 4.7 shows, if her income doubles, her budget line has a parallel shift outward. The new intercepts at 50 = 2Y/pB = (2 * 50)/2 on the burrito axis and 100 = 2Y/pZ = (2 * 50)/1 on the pizza axis are double the original values. If the prices fall by half, her budget line is the same as if her income doubles. The intercept on the burrito axis is 50 = Y/(pB/2) = 50/(2/2), and the intercept on the pizza axis is 100 = Y/(pZ/2) = 50/(1/2). Therefore, Lisa is equally well off if her income doubles or if prices fall by half. Mini-Case Rationing Q& A 4.2 During emergencies, governments frequently ration food, gas, and other staples rather than let their prices rise, as the United States and the United Kingdom did during World War II. Cuban citizens receive a ration book that limits their purchases of staples such as rice, legumes, potatoes, bread, eggs, and meat. Water rationing is common during droughts. During 2010–2013, water quotas were imposed in areas of California, Egypt, Honduras, India, Kenya, New Zealand, Pakistan, Texas, the U.S. Midwest, and Venezuela. Rationing affects consumers’ opportunity sets because they cannot necessarily buy as much as they want at market prices. A government rations water, setting a quota on how much a consumer can purchase. If a consumer can afford to buy 12 thousand gallons a month but the government restricts purchases to no more than 10 thousand gallons a month, how does the consumer’s opportunity set change? Other goods per week 4.4 Constrained Consumer Choice Quota Budget line 4.4 Answer 1. Draw the original opportunity set using a budget line between water and all other goods. In the graph, the consumer can afford to buy up to 12 thousand gallons of water a week if not constrained. The opportunity set, areas A and B, is bounded by the axes and the budget line. 2. Add a line to the figure showing the quota, and determine the new opportunity set: A vertical line at 10 thousand on the water axis indicates the quota. A 0 103 B 10 12 Water, Thousand gallons per month The new opportunity set, area A, is bounded by the axes, the budget line, and the quota line. 3. Compare the two opportunity sets: Because of the rationing, the consumer loses part of the original opportunity set: the triangle B to the right of the 10 thousand gallons line. The consumer has fewer opportunities because of rationing. Constrained Consumer Choice My problem lies in reconciling my gross habits with my net income. —Errol Flynn Were it not for the budget constraint, consumers who prefer more to less would consume unlimited amounts of all goods. Well, they can’t have it all! Instead, consumers maximize their well-being subject to their budget constraints. Now, we have to determine the bundle of goods that maximizes well-being subject to the budget constraint. The Consumer’s Optimal Bundle Given information about Lisa’s preferences (as summarized by her indifference curves) and how much she can spend (as summarized by her budget line), we can determine Lisa’s optimal bundle. Her optimal bundle is the bundle out of all the bundles that she can afford that gives her the most pleasure. Here, we use graphical techniques to find her optimal bundle. We first show that Lisa’s optimal bundle must be on the budget line in Figure 4.8. Bundles that lie on indifference curves above the constraint, such as those on I 3, are not in her opportunity set. Although Lisa prefers Bundle f on indifference curve I 3 to e on I 2, she cannot afford to purchase f. Even though Lisa could buy a bundle inside the budget line, she does not want to do so, because more is better than less: For any bundle inside the constraint (such as d on I 1), another bundle on the constraint has more of at least one of the two goods, and hence she prefers that bundle. Therefore, the optimal bundle must lie on the budget line. We can also show that bundles that lie on indifference curves that cross the budget line (such as I 1, which crosses the constraint at a and c) are less desirable than certain other bundles on the constraint. Only some of the bundles on indifference curve I 1 104 CHAPTER 4 Consumer Choice Lisa’s optimal bundle is e (10 burritos and 30 pizzas) on indifference curve I2. Indifference curve I2 is tangent to her budget line at e. Bundle e is the bundle on the highest indifference curve (highest utility) that she can afford. Any bundle that is preferred to e (such as points on indifference curve I3) lies outside of the opportunity set so she cannot afford them. Bundles inside the opportunity set, such as d, are less desirable than e because they represent less of one or both goods. B, Burritos per semester F IG U RE 4. 8 Consumer Maximization, Interior Solution Budget line g 25 c 20 B 10 e d A 0 f 10 I3 I2 I1 a 30 50 Z, Pizzas per semester lie within the opportunity set: Bundles a and c and all the points on I 1 between them, such as d, can be purchased. Because I 1 crosses the budget line, the bundles between a and c on I 1 lie strictly inside the constraint, so bundles in the opportunity set (area A + B) are preferable to these bundles on I 1 and are affordable. By the more-is-better property, Lisa prefers e to d because e has more of both pizza and burritos than d. By transitivity, e is preferred to a, c, and all the other points on I 1—even those, like g, that Lisa can’t afford. Because indifference curve I 1 crosses the budget line, area B contains at least one bundle that is preferred to—lies above and to the right of—at least one bundle on the indifference curve. Thus, the optimal bundle—the consumer’s optimum—must lie on the budget line and be on an indifference curve that does not cross it. If Lisa is consuming this bundle, she has no incentive to change her behavior by substituting one good for another. So far, we’ve shown that the optimal bundle must lie on an indifference curve that touches the budget line but does not cross it. This condition can hold in two ways. The first is an interior solution, in which the optimal bundle has positive quantities of both goods and lies between the ends of the budget line. The other possibility, called a corner solution, occurs when the optimal bundle is at one end of the budget line, where the budget line forms a corner with one of the axes. Interior Solutions. In Figure 4.8, Bundle e on indifference curve I2 is the optimum bundle. It is in the interior of the budget line away from the corners. Lisa prefers consuming a balanced diet, e, of 10 burritos and 30 pizzas, to eating only one type of food or the other. For the indifference curve I 2 to touch the budget line but not cross it, it must be tangent to the budget line at point e. At the point of tangency, the budget line and the indifference curve have the same slope at the point e where they touch. The slope of the indifference curve, the marginal rate of substitution, measures the rate at which Lisa is willing to trade burritos for pizza: MRS = -MUZ/MUB, Equation 4.1. The slope of the budget line, the marginal rate of transformation, measures the rate at 4.4 Constrained Consumer Choice 105 which Lisa can trade her money for burritos or pizza in the market: MRT = -pZ/pB, Equation 4.5. Thus, Lisa’s utility is maximized at the bundle where the rate at which she is willing to trade burritos for pizza equals the rate at which she can trade: MRS = - pZ MUZ = = MRT. pB MUB (4.6) (Appendix 4B uses calculus to derive Equation 4.6.) Rearranging terms, this condition is equivalent to MUZ MUB . = pZ pB (4.7) Equation 4.7 says that the marginal utility of pizza divided by the price of a pizza (the amount of extra utility from pizza per dollar spent on pizza), MUZ/pZ, equals the marginal utility of burritos divided by the price of a burrito, MUB/pB. Thus, Lisa’s utility is maximized if the last dollar she spends on pizza gets her as much extra utility as the last dollar she spends on burritos. If the last dollar spent on pizza gave Lisa more extra utility than the last dollar spent on burritos, Lisa could increase her happiness by spending more on pizza and less on burritos. Her cousin Spenser is a different story. Q&A 4.3 Nate’s utility function over raspberry jelly, J, and peanut butter, N, is U = JN. Nate’s marginal utility from jelly is MUJ = N, and his marginal utility from peanut butter is MUN = J.5 The raspberry jelly Nate buys is $5 per jar and peanut butter is $10 per jar. Nate has a budget of $100 to allocate to these two items. If Nate maximizes his utility, how much of each good will he consume? Answer 1. Derive Nate’s budget line by setting his expenditure equal to his available budget. The expenditure on each item is its price times the amount consumed, so Nate’s budget, 100, equals the sum of the expenditures on these items two goods: 100 = 5J + 10N. 2. Use Equation 4.7 to find the relationship between N and J. Equation 4.7 states that Nate maximizes his utility if he equalizes his marginal utility per dollar across jelly and peanut butter: MUJ/5 = MUN/10. That is, N/5 = J/10 or N = J/2. 3. Substitute this utility-maximizing condition into the budget equation to determine J and N. Substituting this optimality condition into the budget constraint, we learn that 100 = 5J + 10N = 5J + 10(J/2) = 10J. Solving this expression for J, we find that J = 10. 4. Substitute the solution for J into the budget line to solve for N. Substituting J = 10 into the budget constraint, we learn that 100 = 5J + 10N = 50 + 10N, or 50 = 10N, or N = 5. Thus, Nate’s utility-maximizing bundle is J = 10 and N = 5. marginal utility with respect to J, MUJ, is 0U/0J = 0(JN)/0J = N. Similarly, MUN = 0(JN)/ 0N = J. 5The 106 CHAPTER 4 Consumer Choice Spenser’s indifference curves are flatter than Lisa’s indifference curves in Figure 4.8. That is, he is willing to give up more pizzas for one more burrito than is Lisa. Spenser’s optimal bundle occurs at a corner of the opportunity set at Bundle e: 25 burritos and 0 pizzas. B, Burritos per semester F IG U RE 4. 9 Consumer Maximization, Corner Solution 25 e I3 I2 Budget line I1 50 Z, Pizzas per semester Corner Solutions. Some consumers choose to buy only one of the two goods: a corner solution. They so prefer one good to another that they only purchase the preferred good. Spenser’s indifference curves in Figure 4.9 are flatter than Lisa’s in Figure 4.8. That is, he is willing to trade more pizza for an extra burrito than is Lisa. Spenser’s optimal Bundle e, where he buys 25 burritos and no pizza, lies on an indifference curve that touches the budget line only once, at the upper-left corner. It is on the highest indifference curve that touches the budget line. Mini-Case Why Americans Buy More E-Books Than Do Germans Are you reading this book electronically? E-books are appearing everywhere in the English-speaking world. Thanks to the popularity of the Kindle, iPad, and other e-book readers, in 2012, e-books accounted for 25% of trade books (and 33% of fiction books) sold in the United States and 13% in the United Kingdom. E-books sold well in Australia and Canada as well. In contrast, in Germany, only about 1% of books sold are e-books. Why are e-books more successful in the United States than in Germany? Jürgen Harth of the German Publishers and Booksellers Association attributed the difference to tastes or what he called a “cultural issue.” More than others, Germans love printed books—after all, the modern printing press was invented in Germany. As Harth said, “On just about every corner there’s a bookshop. That’s the big difference between Germany and the United States.” An alternative explanation concerns government regulations and taxes that affect prices in Germany. Even if Germans and Americans have the same tastes, Americans are more likely to buy e-books because they are less expensive than printed books in the United States but e-books are more expensive than printed books in Germany. 4.4 Constrained Consumer Choice 107 Unlike in the United States, where publishers and booksellers can choose what prices to set, Germany regulates book prices. To protect small booksellers, its fixedprice system requires all booksellers to charge the same price, for new printed books. In addition, although e-books can sell for slightly lower prices, they are subject to a 19% tax rather than to the 7% tax that applies to printed books.6 Printed books per year Q& A 4.4 Must we appeal to differences in tastes to explain why Germans and Americans read different types of books, or can taxes and price differences explain this difference? Suppose that Max, a German, and Bob, an American, are avid readers with identical incomes and tastes. Both are indifferent between reading a novel in a traditional book or using an e-reader. Therefore, traditional books and e-books are perfect substitutes and the indifference curves for both Max and Bob have a slope of –1. Assume that the pretax price of e-books is less than for printed books in both Germany and the United States, but that the after-tax price of e-books is higher than for printed books in Germany only. Use an indifference-curve/budget-line analysis to explain why Max would be less inclined to buy e-books than Bob. Answer 1. Describe their indifference curves. Both Max and Bob view e-books and printed books as substitutes, and both have an indifference curve for buying books that is a straight line with a slope of -1, as the figure shows. 2. Describe the slopes of their budget line. With printed books on the vertical axis, Max faces a budget line, LM, that is relatively steep—steeper than his indifference curve—because the German taxes make e-books relatively expensive. Bob has a budget line that is flatter than his indifference curve. 3. Use an indifference curve and a budget line to show why Max and Bob make different choices. As the figure shows, Bob maximizes his utility by spending his entire eM, Max’s optimal bundle book budget on e-books. He chooses the Bundle eB, where his indifference curve I hits his budget line LB on the e-book axis. In contrast, Max spends his entire book budget on printed books, at point eM. If Bob and Max viewed the two types M l L of books as imperfect substitutes and had the usual convex indifference curves, they would each buy a mix of e-books and printed books. However, because of the relatively lower price of e-books in eB, Bob’s optimal bundle LM the United States, Bob would buy relaE-books per year tively more e-books. 6The United Kingdom has a similar difference in tax rates. 108 CHAPTER 4 Consumer Choice Promotions Managers often use promotions to induce consumers to purchase more units. Two of the most frequently used promotions are buy one, get one free (BOGOF) and buy one, get the second one at half price. Such deals create kinks in the consumer’s budget line. Consequently, whether a consumer responds to such offers depends on their tastes (the shape of their indifference curves). Buy One, Get One Free Promotion. In a BOGOF promotion, a customer gets a free unit of the product after buying one unit (or some other number of units) at the regular price. For example, a supermarket might offer a fifth fruit drink for free if the customer buys four at the regular price. Promotions of this type are often used for items like CDs, restaurant meals, movie tickets, and other relatively inexpensive consumer products. A 2013 search of Google for “buy one get one free” found 10.8 million websites. Remarkably, even a realty company, Michael Crews Development, has tried to sell homes using a BOGOF promotion, providing a second $400,000 house to the buyer of a first house at $1.6 million or more. In 2013, the Four Seasons Resort in the Seychelles Islands offered one free night at its fivestar hotel to customers who pay for three nights at the normal rate. The effect of such promotions on purchasing behavior can be illustrated using indifference curves and budget lines. Before the promotion was announced, Angela and Betty were separately planning to stay at the hotel for two nights each this month. Each has the same income and allocates the same budget to her vacation. Figure 4.10 shows that Angela takes advantage of the promotion and Betty does not because their tastes differ. Both panels of the figure show the same budget lines. The horizontal axis shows the nights spent at the hotel per month and the vertical axis measures all other goods per month. Their initial budget line before the promotion, L1, is a standard downward sloping line, where the slope depends on the ratio of the full price of a hotel room to the price of other goods. The new BOGOF budget line, L2, is the same as the initial budget line for stays of fewer than three nights. However, if Angela or Betty pays for three nights, she gets an extra night for free. That is, she can get a fourth night with no reduction in her consumption of other goods. Therefore, her new budget line has a horizontal segment one night wide starting at three nights. For additional nights (beyond four) she would pay the regular price, so L2 resumes its same downward slope for stays exceeding four nights. In panel a, Angela’s indifference curve I 1 is tangent to L1 at point x, which is located at two nights on the horizontal axis. Because I 1 is the highest indifference curve that touches her pre-promotion budget line, she chooses to spend two nights at the resort. However, her indifference curve I 1 cuts the new budget line L2, so she can do better. A higher indifference curve, I 2, touches L2 at point y, where she chooses to stay four nights. That is, Angela would prefer to purchase three nights and get an extra night for free with the promotion than pay for and stay only two nights. Betty’s indifference curves in panel b differ from Angela’s. Again, we assume that initially Betty chooses to stay two nights at Bundle x where her indifference 4.4 Constrained Consumer Choice 109 F IG U RE 4. 10 BOGOF Promotion (a) Angela (b) Betty Other goods per month promotion than pay for and stay only two nights: Because her indifference curve I1 cuts the new budget line L2, there’s a higher indifference curve, I 2, that touches L2 at point y, where she chooses to stay four nights. (b) Without the promotion, Betty chooses to stay two nights at x where her indifference curve I3 is tangent to L1. Because I 3 does not cut the new budget line L2, no higher indifference curve can touch L2, so Betty stays only two nights, at x, and does not take advantage of the BOGOF promotion. Other goods per month Angela and Betty are separately deciding how many nights to stay at the resort. Without the promotion, Angela or Betty’s initial budget line is L1. With the BOGOF promotion where if either stays three nights, she gets the fourth night for free, the new budget line is L2. (a) Without the promotion, Angela’s indifference curve I1 is tangent to L1 at point x, so she chooses to spend two nights at the resort. With the BOGOF promotion, Angela prefers to purchase three nights and get an extra night for free with the I1 I2 x y L1 2 3 x I3 L1 L2 , BOGOF 4 Rooms, Nights per month 2 3 L2 , BOGOF 4 Rooms, Nights per month curve I 3 is tangent to L1. Because I 3 is flatter than Angela’s I 1 in panel a (Betty is willing to give up fewer other goods for another night at the resort than is Angela), I 3 does not cut the new budget line L2. Thus, no higher indifference curve can touch L2, so Betty stays only two nights, at x, and does not take advantage of the promotion BOGOF Versus a Half-Price Promotion. As we’ve just seen, whether the hotel’s BOGOF promotion induces consumers to buy extra units depends on the consumers’ tastes: Only a customer whose pre-promotion indifference curve crosses the new budget line will participate in the promotion. Consequently, another promotion may be more effective than BOGOF if a manager can design a promotion such that consumers’ indifference curves must cross the new budget line so that consumers will definitely participate. As an alternative to the BOGOF promotion (“the fourth night free if you pay for three nights”), the resort could offer a half-price promotion in which, after staying two nights at full price, the next two nights are half the usual price. The resort earns the same revenue from either promotion if someone stays four nights. Figure 4.11 reproduces the information in Betty’s panel b from the Figure 4.10 and adds a new half-price promotion constraint, L3. The original, no-promotion budget line, L1, is a light-blue line. The BOGOF budget line, L2, is a dark-blue dashed line. The half-price budget line, L3, is a dark-blue solid line. For stays of more than two nights up to four nights, the price of a room is cut in half, so the slope of L3 is half as steep as it is for the first two full-price nights. For stays of more than four nights, the full-price is charged, so the slope of L3 for more than four nights is the same as on L1 and L2. 110 CHAPTER 4 Consumer Choice The resort’s BOGOF promotion, which provides a fourth night free if one pays for three nights, creates a kink in the budget line L2. With the half-price promotion, budget line L3, the third and fourth nights are half price to a customer who pays full price for the first two nights, hence L3 is half as steep at L1 from two to four nights. Before either promotion is announced, Betty planned to stay two nights, Bundle x, where her indifference curve I3 is tangent to the original budget line L1. Because Betty’s original indifference curve, I3 does not cross L2, she will not take advantage of the BOGOF promotion. However, because I3 crosses the half-price promotion budget line L3, Betty takes advantage of the promotion. Betty’s optimal bundle is y, where she stays three nights, which is located where her indifference curve I4 is tangent to the half-price promotion line L3. Other goods per month F IG U RE 4. 11 Half-Price Versus BOGOF Promotions I3 I4 x y L2 L1 2 3 L3 4 Rooms, Nights per month Although Betty’s original indifference curve I 3 does not cross the BOGOF budget line L2, it must cross the L3 budget line of the half-price promotion. We know that I 3 crosses L2 because the original indifference curve I 3 is tangent to L1 at x, while L3 is half as steeply sloped as L1 at x, so it cannot be tangent to I 3 and must cut I 3. Because I 3 crosses L3, we know that Betty has a higher indifference curve that touches L3. Betty chooses to stay three nights, where her higher indifference curve I 4 is tangent to L3 at y. Ma nagerial I mplication Designing Promotions 4.5 When deciding whether to use either BOGOF or half-price promotions, a manager should take costs into account. For example, offering such a promotion is more likely to pay if a hotel has excess capacity so that the cost of providing a room for an extra night’s stay is very low. The manager also needs to determine whether its customers are more like Angela or more like Betty. To design an effective promotion, a manager should use experiments to learn about customers’ preferences. For example, a manager could offer each promotion for a short period of time and keep track of how many customers respond to each promotion, how many nights they choose to stay, and by how much the promotion increased the firm’s profit. Deriving Demand Curves We use consumer theory to show how much the quantity demanded of a good falls as its price rises. An individual chooses an optimal bundle of goods by picking the point on the highest indifference curve that touches the budget line. A change in a price causes the budget line to rotate, so that the consumer chooses a new optimal bundle. By varying one price and holding other prices and income constant, we determine how the quantity demanded changes as the price changes, which is the information we need to draw the demand curve. 4.5 Deriving Demand Curves 111 We derive a demand curve using the information about tastes from indifference curves. To illustrate how to construct a demand curve, we estimated a set of indifference curves between recorded music—primarily tracks or songs purchased from iTunes, Amazon, Rhapsody, or other similar sources—and live music (at clubs, concerts, and so forth) using data for British young people (ages 14–24). Of these young people, college students spend about £18 per quarter on live music and £12 per quarter on music tracks for a total budget of £30 for music.7 Panel a of Figure 4.12 shows three of the estimated indifference curves for a typical British college student, whom we call Jack.8 These indifference curves are convex to the origin: Jack views live music and tracks as imperfect substitutes. We can construct Jack’s demand curve for music tracks by holding his budget, his tastes, and the price of live music constant at their initial levels and varying the price of tracks. The vertical axis in panel a measures the amount of live music that Jack consumes each quarter, and the horizontal axis measures the number of tracks he buys per quarter. Jack spends Y = £30 per year on live music and tracks. We set the price of live music, pm, at £1 by choosing the units appropriately (so the units do not correspond to a concert or visit to a club). The price of tracks, pt, is £0.5 per track. Jack can buy 30 (= Y/pm = 30/1) units of live music if he spends all his money on that, or up to 60 (= Y/pt = 30/0.5) tracks if he buys only tracks. The slope of his budget line, L3, is -pt/pm = -0.5/1 = -0.5. Given budget line L3, Jack consumes 18 units of live music per quarter and 24 tracks per quarter, Bundle e3, which is determined by the tangency of indifference curve I 3 and budget line L3. Now suppose that the price of tracks doubles to £1 per track while the price of live music and his budget remain constant. If he were to spend all his money on live music, he could buy the same 30 units as before, so the intercept on the vertical axis of L2 is the same as for L3. However, if he were to spend all his money on tracks, he could buy only half as much as before (30 instead of 60 tracks), so L2 hits the horizontal axis half as far from the origin as L3. As a result, L2 has twice as steep a slope, -pt/pm = -1/1 = -1, as does L3. The slope is steeper because the price of tracks has fallen relative to the price of live music. Because tracks are now relatively more expensive, Jack buys relatively fewer of them. He chooses Bundle e2, where his indifference curve I 2 is tangent to L2. He now buys only 12 tracks per quarter (compared to 24 at e3.)9 If the price of a track doubles again to £2, Jack consumes Bundle e1, 6 tracks per quarter. The higher the price of tracks, the less happy Jack is because he consumes less music on the same budget: He is on indifference curve I 1, which is lower than I 2 or I 3. We can use the information in panel a to draw Jack’s demand curve for tracks, D1, in panel b. Corresponding to each possible price of a track on the vertical axis of panel b, we record on the horizontal axis the number of tracks that Jack chooses in panel a. 7Data on total expenditures are from The Student Experience Report, 2007, www.unite-students.com, while budget allocations between live and recorded music are from the 2008 survey into the Music Experience and Behaviour in Young People produced by the British Music Rights and the University of Hertfordshire. 8The estimated utility function is U = M 0.6T 0.4, where M is the units of live music and T is the number of tracks. figure shows that he buys the same amount of live music, 18 units, when the price of tracks rises. This property is due to the particular utility function (a Cobb-Douglas) that we use in this example. With most other utility functions, the quantity of live music would change. 9The 112 CHAPTER 4 Consumer Choice F IG U RE 4. 12 Deriving an Individual’s Demand Curve M, Live music per quarter If the price of recorded songs—tracks of music—rises, holding constant the price of live (a) music (at £1 per unit), the music budget (at £30 per quarter), and tastes, the typical British college student, Jack, buys fewer tracks. This figure is based on our estimate of the typical student’s utility function. (a) On budget line L3, the price of a track is £0.5. Jack’s indif30 ference curve I3 is tangent to L3 at Bundle e3, where he buys 18 units of live music and 24 tracks per quarter. If the price of a track doubles to £1, the new budget line is L2, and Jack reduces the number of tracks he demands to 12 per quarter. If the price doubles again, to 18 £2, Jack buys only 6 tracks. (b) By varying the price of a track, we trace out Jack’s demand curve, D1. The tracks price-quantity combinations E1, E2, and E3 on the demand curve for tracks in panel b correspond to optimal Bundles e1, e2, and e3 in panel a. e1 e3 e2 I3 I2 I1 L1 (pT = £2) 12 6 L2 (pT = £1) 30 24 60 T, Tracks per quarter pT, £ per track (b) L3 (pT = £0.5) E1 2 E2 1 E3 0.5 D 1, Demand for tracks 6 12 24 T, Tracks per quarter Points E1, E2, and E3 on the demand curve in panel b correspond to Bundles e1, e2, and e3 in panel a. Both e1 and E1 show that when the price of a track is £2, Jack demands 6 tracks per quarter. When the price falls to £1, Jack increases his consumption to 12 tracks, point E2. The demand curve, D1, is downward sloping as predicted by the Law of Demand. 4.6 Behavioral Economics 4.6 113 Behavioral Economics So far, we have assumed that consumers are rational, maximizing individuals. A new field of study, behavioral economics, adds insights from psychology and empirical research on human cognitive and emotional biases to the rational economic model to better predict economic decision making.10 We discuss three applications of behavioral economics in this section: tests of transitivity, the endowment effect, and salience. Later in this book, we examine the psychology of decision making in networks (Chapter 9), strategic interactions (Chapter 13), and under uncertainty (Chapter 14). Tests of Transitivity In our presentation of the basic consumer choice model at the beginning of this chapter, we assumed that consumers make transitive choices. But do consumers actually make transitive choices? A number of studies of both humans and animals show that preferences usually are transitive and hence consistent with our assumption. However, some situations can induce intransitive choices. Weinstein (1968) used an experiment to determine how frequently people give intransitive responses. None of the subjects knew the purpose of the experiment. They were given choices between ten goods, offered in pairs, in every possible combination, and were told that each good had a value of $3. Weinstein found that 93.5% of the responses of adults—people over 18 years old—were transitive. However, only 79.2% of children aged 9–12 gave transitive responses. Based on these results, one might conclude that it is appropriate to assume that adults exhibit transitivity for most economic decisions. On the other hand, one might modify the theory when applying it to children or when novel goods are introduced. Economists normally argue that rational people should be allowed to make their own consumption choices so as to maximize their well-being. However, some might conclude that children’s lack of transitivity or rationality provides one justification for political and economic restrictions and protections placed on young people. Endowment Effects Experiments show that people have a tendency to stick with the bundle of goods that they currently possess. One important reason for this tendency is called the endowment effect, which occurs when people place a higher value on a good if they own it than they do if they are considering buying it. We normally assume that an individual can buy or sell goods at the market price. Rather than rely on income to buy some mix of two goods, an individual who was endowed with several units of one good could sell some and use that money to buy units of another good. We assume that a consumer’s endowment does not affect the indifference curve map. In a classic buying and selling experiment, Kahneman et al. (1990) challenged this 10The introductory chapter of Camerer et al. (2004) and DellaVigna (2009) are excellent surveys of the major papers in this field and heavily influenced the following discussion. 114 CHAPTER 4 Consumer Choice assumption. In an undergraduate law and economics class at Cornell University, 44 students were divided randomly into two groups. Members of one group were given coffee mugs that were available at the student store for $6. Those students endowed with a mug were told that they could sell it and were asked the minimum price that they would accept for the mug. The subjects in the other group, who did not receive a mug, were asked how much they would pay to buy the mug. Given the standard assumptions of our model and that the subjects were chosen randomly, we would expect no difference between the selling and buying prices. However, the median selling price was $5.75 and the median buying price was $2.25. Sellers wanted more than twice what buyers would pay. This type of experiment has been repeated many times with many variations and consistently demonstrates an endowment effect. However, some economists believe that this result has to do with the experimental design. Plott and Zeiler (2005) argued that if you take adequate care to train the subjects in the procedures and make sure they understand them, we no longer find this result. List (2003) examined the actual behavior of sports memorabilia collectors and found that amateurs who do not trade frequently exhibited an endowment effect, unlike professionals or amateurs who traded a lot. Thus, experience may reduce or even eliminate the endowment effect, and people who buy goods for resale may be less likely to become attached to these goods. Others accept the results and have considered how to modify the standard model to reflect the endowment effect (Knetsch, 1992). One implication of these experimental results is that people will only trade away from their endowments if prices change substantially. This resistance to trade could be captured by having a kink in the indifference curve at the endowment bundle. (We showed indifference curves with a kink at a 90° angle in panel b of Figure 4.4.) These indifference curves could have an angle greater than 90°, and the indifference curve could be curved at points other than at the kink. If the indifference curve has a kink, the consumer does not shift to a new bundle in response to a small price change, but may shift if the price change is large. Mini-Case How You Ask the Question Matters One practical implication of the endowment effect is that consumers’ behavior may differ depending on how a choice is posed. Many workers are offered the choice of enrolling in their firm’s voluntary tax-deferred retirement (pension) plan, called a 401(k) plan. The firm can pose the choice in two ways: It can automatically sign up employees for the program and let them opt out if they want, or it can tell employees that to participate in the program they must sign up (opt in) to participate. These two approaches might seem identical, but the behaviors they lead to are not. Madrian and Shea (2001, 2002) found that well over twice as many workers participate if they are automatically enrolled (but may opt out) than if they must opt in: 86% versus 37%. In short, inertia matters. Because of this type of evidence, federal law was changed in 2006 and 2007 to make it easier for employers to enroll their employees in their 401(k) plans automatically. According to Aon Hewitt, the share of large firms that automatically enroll new hires in 401(k) plans was 67% in 2012, up from 58% in 2007. Participation in defined-contribution retirement plans in large companies rose from 67% in 2005 to 76% in 2010, due to the increased use of automatic enrollment. 4.6 Behavioral Economics 115 Salience We often use economic theories based on the assumption that decision makers are aware of all relevant information. In this chapter, we assume that consumers know their own income, relevant prices, and their own tastes, and hence they make informed decisions. Behavioral economists and psychologists have demonstrated that people are more likely to consider information if it is presented in a way that grabs their attention or if it takes relatively little thought or calculation to understand. Economists use the term salience, in the sense of striking or obvious, to describe this idea. For example, tax salience is awareness of a tax. If a store’s posted price includes the sales tax, consumers observe a change in the price as the tax rises. On the other hand, if a store posts the pretax price and collects the tax at the cash register, consumers are less likely to note that the post-tax price has increased when the tax rate increases. Chetty et al. (2007) compared consumers’ response to a rise in an ad valorem sales tax on beer (called an excise tax) that is included in the posted price to an increase in a general ad valorem sales tax, which is collected at the cash register but not reflected in the posted price. An increase in either tax has the same effect on the final price, so an increase in either tax should have the same effect on purchases if consumers pay attention to both taxes.11 However, a 10% increase in the posted price, which includes the excise tax, reduces beer consumption by 9%, whereas a 10% increase in the price due to a rise in the sales tax that is not posted reduces consumption by only 2%. Chetty et al., also conducted an experiment where they posted tax-inclusive prices for 750 products in a grocery store and found that demand for these products fell by about 8% relative to control products in that store and comparable products at nearby stores. One explanation for the lack of an effect of a tax on consumer behavior is consumer ignorance. For example, Furnham (2005) found that even at the age of 14 or 15, young people do not fully understand the nature and purpose of taxes. Similarly, unless the tax-inclusive price is posted, many consumers ignore or forget about taxes. An alternative explanation for ignoring taxes is bounded rationality: people have a limited capacity to anticipate, solve complex problems, or enumerate all options. To avoid having to perform hundreds of calculations when making purchasing decisions at a grocery store, many people chose not to calculate the taxinclusive price. However, when post-tax price information is made available to them without the need to do calculations, consumers make use of it. One way to modify the standard model to incorporate bounded rationality is to assume that people incur a cost to making calculations—such as the time taken or the mental strain—and that deciding whether to incur this cost is part of their rational decisionmaking process. People incur this calculation cost only if they think the gain from a better choice of goods exceeds the cost. More people pay attention to a tax when the tax rate is high or when their demand for the good is elastic (they are sensitive to price). Similarly, some people are more likely to pay attention to taxes when making large, one-time purchases—such as for a computer or car—rather than small, repeated purchases— such as for a bar of soap. p* = p(1 + β)(1 + α), where p is the pretax price, α is the general sales tax, and β is the excise tax on beer. 11The final price consumers pay is 116 CHAPTER 4 Consumer Choice Thus inattention due to bounded rationality is rational—consumers are doing the best they can in view of their limited powers of calculation. In contrast, inattention due to lack of salience is not rational. People would do better if they paid attention to less obvious information, but they just don’t bother. M a nagerial Implication Simplifying Consumer Choices Managerial Solution Paying Employees to Relocate Today’s consumers are often overwhelmed by choices. Cable TV subscribers must select from many possible channels, most of which the consumer has never seen. Because consumers have bounded rationality, most consumers dislike considering all the possibilities and making decisions. To avoid making decisions, many consumers do not buy these services and goods even though they would greatly benefit from making these purchases. To avoid this problem, good managers make decision-making easier for consumers. For example, they may offer default bundles so that consumers don’t have to make a large number of difficult decisions. Cable TV companies package groups of channels by content. Instead of choosing between possibly hundreds of individual channels, a consumer can opt for the sports package or the movie package. Instead of thinking through each option, the customer can make a much easier decision such as “I like sports” or “I like movies” and is more likely to make a purchase. We conclude our analysis of consumer theory by returning to the managerial problem posed in the introduction of this chapter: How can a firm’s human resources manager use consumer theory to optimally compensate employees who are transferred to other cities? Relocation managers collect information about the cost of living in various cities around the world from government sources (U.S. Defense Department, U.S. Government Services Administration, U.S. Office of Personnel Management, U.S. State Department), publications (Money Magazine, Monthly Labor Review), websites (bankrate.com, bestplaces.net, citymayors.com, homefair.com, moving.com), and data and human resources consulting firms (such as EIU Data Services, Mercer Consulting, and Runzheimer International).12 From this information, managers know that it is more expensive to buy the same bundle of goods in one city than another and that the relative prices of goods differ across cities. As we noted in the Managerial Problem, most firms say they pay their employees enough in their new city to buy the same bundle of goods as in their original city. We want to investigate whether such firms are paying employees more than they have to for them to relocate. We illustrate our reasoning using an employee who cares about only two goods. Alexx’s firm wants to transfer him from its Seattle office to its London office, where he will face different prices and cost of living. Alexx, who doesn’t care 12The University of Michigan’s library maintains an excellent list of cost-of-living sources, www .lib.umich.edu/govdocs/steccpi.html, for comparisons of both U.S. and international cities. See cgi.money.cnn.com/tools/costofliving/costofliving.html or www.bankrate.com/calculators/ mortgages/moving-cost-of-living-calculator.aspx?ec_id=m1025821 for calculators that compare U.S. cities’ cost of living. An international calculator is available at www.numbeo.com. Entertainment per year 4.6 Behavioral Economics LL L* l LS l* 117 whether he lives in Seattle or London, spends his money on housing and entertainment. Like most firms, his employer will pay him an after-tax salary in British pounds such that he can buy the same bundle of goods in London that he is currently buying in Seattle. Will Alexx benefit by moving to London? Could his employer have induced him to relocate for less money? Alexx’s optimal bundle, s, in Seattle is determined by the tangency of his indifference curve I 1 and his Seattle budget line LS in the figure. It cost 53% more to live in London than Seattle on average in 2011. If the prices of all goods are exactly 53% higher in London than in Seattle, the relative costs of housing and entertainment is the same in both cities. In that case, if his firm raises Alexx’s income by 53%, his budget line does not change and he buys the same bundle, s, and his level of utility is unchanged. However, relative prices are not the same in s both cities. Controlling for quality, housing is I2 relatively more expensive and entertainment— I1 concerts, theater, museums, zoos—is relatively less expensive in London than in Seattle. Thus, if Housing per year Alexx’s firm adjusts his income so that Alexx can buy the same bundle, s, in London as he did in Seattle, his new budget line in London, LL, must go through s but have a different slope. Because entertainment is relatively less expensive than housing in London compared to Seattle, if Alexx spends all his money on entertainment, he can buy more in London than in Seattle. Similarly, if he spends all his money on housing, he can buy less housing in London than in Seattle. As a result, LL hits the vertical axis at a higher point than the LS line and cuts the LS line at Bundle s. Alexx’s new optimal bundle, l, is determined by the tangency of I 2 and LL. Thus, because relative prices are different in London and Seattle, Alexx is better off with the transfer after receiving the firm’s 53% higher salary. He was on I 1 and is now on I 2. Alexx could buy his original bundle, s, but chooses to substitute toward entertainment, which is relatively inexpensive in London, thereby raising his utility. Consequently, his firm could have induced him to move with less compensation. If the firm lowers his income, the London budget line he faces will be closer to the origin but will have the same slope as LL. The firm can lower his income until his lower-income London budget line, L*, is tangent to his Seattle indifference curve, I 1, at Bundle l*. Alexx still substitutes toward the relatively less expensive entertainment in London, but he is only as well off as he was in Seattle (he remains on the same indifference curve as when he lived in Seattle). Thus, his firm can induce Alexx to transfer to London for less than what the firm would have to pay so that Alexx could buy his original Seattle consumption bundle in London. 118 CHAPTER 4 Consumer Choice S U MMARY Consumers maximize their utility (well-being) subject to constraints based on their income and the prices of goods. 1. Consumer Preferences. To predict consumers’ responses to changes in constraints, economists use a theory about individuals’ preferences. One way of summarizing a consumer’s preferences is with a family of indifference curves. An indifference curve consists of all bundles of goods that give the consumer a particular level of utility. On the basis of observations of consumers’ behavior, economists assume that consumers’ preferences have three properties: completeness, transitivity, and more is better (nonsatiation). Given these three assumptions, indifference curves have the following properties: ● Consumers get more utility or satisfaction from bundles on indifference curves that are farther from the origin. ● There is an indifference curve through any given bundle. ● Indifference curves cannot cross. ● Indifference curves slope downward. 2. Utility. Economists use the term utility to describe the set of numerical values that reflect the relative rankings of bundles of goods. By comparing the utility a consumer gets from each of two bundles, we know that the consumer prefers the bundle with the higher utility. The marginal utility, MU, from a good is the extra utility a person gets from consuming one more unit of that good, holding the consumption of all other goods constant. The rate at which a consumer is willing to substitute Good 1 for Good 2, the marginal rate of substitution, MRS, depends on the relative amounts of marginal utility the consumer gets from each of the two goods. 3. The Budget Constraint. The amount of goods consumers can buy at given prices is limited by their income. As a result, the greater a consumer’s income or the lower the prices of goods, the more the consumer can buy. The consumer has a larger opportunity set. The marginal rate of transformation (MRT) shows how much of one good the consumer must give up in trade for one more unit of another good. The MRT depends on the relative prices of the two goods. 4. Constrained Consumer Choice. Each person picks an affordable bundle of goods that maximizes his or her utility. If an individual consumes both Good 1 and Good 2 (an interior solution), the individual’s utility is maximized when the following four equivalent conditions hold: ● The indifference curve for Goods 1 and 2 is tangent to the budget line. ● The consumer buys the bundle of goods that is on the highest obtainable indifference curve. ● The consumer’s marginal rate of substitution (the slope of the indifference curve) equals the marginal rate of transformation (the slope of the budget line). ● The last dollar spent on Good 1 gives the consumer as much extra utility as the last dollar spent on Good 2. Sometimes, consumers choose to buy only one of the two goods (corner solutions). The last dollar spent on the good that is purchased gives more extra utility than would spending a dollar on the other good, which the consumer chooses not to buy. 5. Deriving Demand Curves. Individual demand curves can be derived by using the information about preferences contained in a consumer ’s indifference curve map. By varying the price of one good while holding other prices and income constant, we find how the quantity demanded varies as its own price changes, which is the information we need to draw the good’s demand curve. Consumers’ preferences, which are captured by the indifference curves, determine the shape of the demand curve. 6. Behavioral Economics. Using insights from psychology and empirical research on human cognition and emotional biases, economists are starting to modify the rational economic model to better predict economic decision making. Some decision makers, particularly children, fail to make transitive choices in certain circumstances. Some consumers exhibit an endowment effect: They place a higher value on a good if they own it than they do if they are considering buying it. Consequently, they are less sensitive to price changes and hence less likely to trade than would be predicted by the standard economic model. Consumers are more inclined to take into account information that is readily available to them (salient), while ignoring other information. Questions 119 Q U E S T ION S All exercises are available on MyEconLab; * = answer at the back of this book. 1. Consumer Preferences 1.1. Give as many reasons as you can why we believe that economists assume that the more-is-better property holds and explain how these explanations relate to the results in the Mini-Case “You Can’t Have Too Much Money.” *1.2. Arthur spends his income on bread and chocolate. He views chocolate as a good but is neutral about bread, in that he doesn’t care if he consumes it or not. Draw his indifference curve map. 1.3. Show that an indifference curve a. Cannot be thick (cannot have positive thickness, rather than being just a line). b. Cannot bend backward (forming a “hook” at the end). 1.4. Which of the following pairs of goods are complements and which are substitutes? Are the goods that are substitutes likely to be perfect substitutes for some or all consumers? a. b. c. d. A popular novel and a gossip magazine A camera and film A pair of sunglasses and a stick of butter A Panasonic Blu-ray player and a Samsung Blu-ray player 1.5. Give as many reasons as you can why we believe that indifference curves are convex to the origin. 2. Utility *2.1. William eats hot dogs only with mustard and consumes mustard only with hot dogs. He puts one unit of mustard on each hot dog he eats. Show his preference map. What is his utility function? 2.2. If Mia views two cups of tea as a perfect substitute for one cup of coffee and vice versa, what is her marginal rate of substitution between tea and coffee? 2.3. Lorna consumes cans of anchovies, A, and boxes of biscuits, B. Each of her indifference curves reflects strictly diminishing marginal rates of substitution. If A = 2 and B = 2, her marginal rate of substitution between cans of anchovies and boxes of biscuits equals - 1( = MUA/MUB). Will she prefer a bundle with three cans of anchovies and a box of biscuits to a bundle with two of each? Why? *2.4. Andy purchases only two goods, apples (a) and kumquats (k). He has an income of $40 and can buy apples at $2 per pound and kumquats at $4 per pound. His utility function is U(a, k) = 3a + 5k. That is, his constant marginal utility for apples is 3 and his constant marginal utility for kumquats is 5. What bundle of apples and kumquats should Andy purchase to maximize his utility? Why? 3. The Budget Constraint 3.1. Yuka consumes mangos and oranges. She is given four mangos and three oranges. She can buy or sell mangos for $2 each. Similarly, she can buy or sell an orange for $1. If Yuka has no other source of income, draw her budget line and write the equation. 3.2. If the budget line is Y = 500 = pBB + pZZ = 5B + 10Z, what is the marginal rate of transformation, MRT, between B (burritos) and Z (pizza)? 3.3. Change Q&A 4.1 so that Lisa’s budget and the price of pizza double, but the price of burritos remains constant. Show how her budget constraint and opportunity set changes. Is Lisa necessarily better off than before these changes? (Hint: What happens to the intercepts of the budget line?) *3.4. Dale goes to the opera and ice hockey games. Draw a budget line for Dale. If the government imposes a 25% income tax on her, what happens to her budget line and opportunity set? (Hint: See Q&A 4.2.) 3.5. Alexander spends all his money on chocolate bars and songs that he downloads. The price of a chocolate bar and of a song is $1 each. His parents give him an allowance of $50 and four chocolate bars each month. Draw his opportunity set, assuming that he cannot sell the chocolate bars to his friends. How does the oppurtunity set change if he can sell the chocolate bars at the market price? 4. Constrained Consumer Choice 4.1. Linda loves buying shoes and going out to dance. Her utility function for pairs of shoes, S, and the number of times she goes dancing per month, T, is U(S, T) = 2ST, so MUS = 2T and MUT = 2S. It costs Linda $50 to buy a new pair of shoes or to spend an evening out dancing. Assume that she has $500 to spend on clothing and dancing. (Hint: See Q&A 4.3.) a. What is the equation for her budget line? Draw it (with T on the vertical axis), and label the slope and intercepts. 120 CHAPTER 4 Consumer Choice b. What is Linda’s marginal rate of substitution? Explain. c. Use math to solve for her optimal bundle. Show how to determine this bundle in a diagram using indifference curves and a budget line. *4.2. Nadia likes spare ribs, R, and fried chicken, C. Her utility function is U = 10R2C. Her marginal utilities are MUR = 20RC and MUC = 10R2. Her weekly income is $90, which she spends on only ribs and chicken. a. If she pays $10 for a slab of ribs and $5 for a chicken, what is her optimal consumption bundle? Show her budget line, indifference curve, and optimal bundle, e1, in a diagram. b. Suppose the price of chicken doubles to $10. How does her optimal consumption of chicken and ribs change? Show her new budget line and optimal bundle, e2, in your diagram. 4.3. Lucas chooses between water and all other goods. If he spends all his money on water, he can buy 15 thousand gallons per week. At current prices, his optimal bundle is e1, where he buys both types of goods. Show e1 in a diagram. During a drought, the government limits the number of gallons per week that he may purchase to 10 thousand. Using diagrams, discuss under which conditions his new optimal bundle, e2, will be the same as e1. If the two bundles differ, can you state where e2 must be located relative to e1? *4.4. Gasoline is typically less expensive in the United States than across the border in Canada, but now suppose that U.S. gasoline price rises above that in Canada due to a change in taxes. How would the gasolinepurchasing behavior of a person who lives equally close to gas stations in both countries change? Answer using an indifference curve and budget line diagram. if the chain had a physical presence (a “brick” store as opposed to a “click” store) in those states. Thus, those states collected taxes on Best Buy’s online sales, because it had stores in each of those states, but they did not collect taxes from Amazon.com because it did not have physical locations in those states. Starting in 2012, Amazon had to pay taxes in these states. After the tax was imposed on Amazon, Best Buy had a 4% to 6% increase in its online sales in those states relative to the rest of the chain (www.bizjournals.com/twincities/ news/2013/01/11/best-buys-online-sales-up-in-states. html). Use an indifference-curve/budget-line diagram to show why Best Buy’s sales rose after taxes were imposed on Amazon. (Hint: Start by drawing a typical consumer’s indifference curve between buying a good from Amazon or from Best Buy.) 4.8. The local swimming pool charges nonmembers $10 per visit. If you join the pool, you can swim for $5 per visit but you have to pay an annual fee of F. Use an indifference curve diagram to find the value of F such that you are indifferent between joining and not joining. Suppose that the pool charged you exactly that value of F. Would you go to the pool more or fewer times than if you did not join? For simplicity, assume that the price of all other goods is $1. 4.9. Based on panel a in Figure 4.10, show that Angela would accept the BOGOF promotion or the halfprice promotion. Show that she may choose to stay either three or four nights with the half-price promotion depending on the exact shape of her indifference curves. 5. Deriving Demand Curves 4.6. Ralph usually buys one pizza and two colas from the local pizzeria. The pizzeria announces a special: All pizzas after the first one are half-price. Show the original and new budget line. What can you say about the bundle Ralph will choose when faced with the new constraint? 5.1. Some of the largest import tariffs (taxes on only imported goods) are on shoes. Strangely, the tariff is higher on cheaper shoes. The highest U.S. tariff, 67%, is on a pair of $3 canvas sneakers, while the tariff on $12 sneakers is 37%, and that on $300 Italian leather imports is 0%. (Adam Davidson, “U.S. Tariffs on Shoes Favor Well-Heeled Buyers,” National Public Radio, June 12, 2007, www.npr.org/templates/ story/story.php?storyId=10991519.) Laura buys either inexpensive, canvas sneakers ($3 before the tariff) or more expensive gym shoes ($12 before the tariff) for her many children. Use an indifference curve and budget line figure to show how imposing these unequal tariffs affects the bundle of shoes that she buys compared to what she would have bought in the absence of tariffs. Can you confidently predict whether she’ll buy relatively more expensive gym shoes after the tariff? Why or why not? 4.7. Until 2012, California, Texas, and Pennsylvania required firms to collect sales taxes for online sales 5.2. Draw diagrams similar to Figure 4.12 but with different shape indifference curves to show that as the 4.5. Suppose we change Q&A 4.4 so that Max and Bob have indifference curves that are convex to the origin. Use a figure to discuss how the different slopes of their budget lines affect the choices they make. Can you make any unambiguous statements about how many total books each can buy? Can you make an unambiguous statement if you know that Bob’s budget line goes through Max’s optimal bundle? Questions price of tracks rises, the amount of live music Jack will buy may rise or fall. 5.3. Derive and plot Olivia’s demand curve for pie if she eats pie only à la mode and does not eat either pie or ice cream alone (pie and ice cream are complements). 5.4. According to towerswatson.com, at large employers, 48% of employees earning between $10,000 and $24,999 a year participated in a voluntary retirement savings program, compared to 91% who earned more than $100,000. We can view savings as a good. In a figure, plot savings versus all other goods. Show why a person is more likely to “buy” some savings (put money in a retirement account) as the person’s income rises. 6. Behavioral Economics 6.1. Illustrate the logic of the endowment effect using a kinked indifference curve. Let the angle be greater than 90°. Suppose that the prices change, so the slope of the budget line through the endowment changes. Use the diagram to explain why an individual whose endowment point is at the kink will only trade from the endowment point if the price change is substantial. *6.2. Why would a consumer’s demand for a product change when the product price is quoted inclusive of taxes rather than before tax? Do you think fewer people would apply for a job if the salary were quoted after deducting income tax rather than in pretax form? 7. Managerial Problem 7.1. In the Managerial Problem, suppose that entertainment is relatively more expensive in London than in Seattle so that the LL budget line cuts the LS budget line from below rather than from above as in the figure in the Managerial Solution. Show that the conclusion that Alexx is better off after his move if his 121 new income allows him to buy bundle s still holds. Explain the logic behind the following statement: “The analysis holds as long as the relative prices differ in the two cities. Whether both prices, one price, or neither price in London is higher than in Seattle is irrelevant to the analysis.” 8. Spreadsheet Exercises 8.1. Lucy has just been promoted to a managerial position and given a new office. She is very fond of small Persian carpets and Native American paintings and wants to get some carpets and paintings for her office. Her utility function for carpets (x) and paintings (y) is given by U(x, y) = 2xy. Using Excel’s charting tool, draw an indifference curve for U = 4 and another one for U = 6, where both indifference curves contain 1, 2, 4, and 8 carpets on a graph with carpets on the horizontal axis and paintings on the vertical axis. 8.2. As described in Exercise 8.1, Lucy wants carpets and paintings for her office. Her company has given her a budget of $7,200 for this purpose. Persian carpets of the size that she wants can be purchased for $900 each and paintings from a local Native American artist cost $400 each. a. Using Excel’s charting tool, draw Lucy’s budget constraint if her budget is $5,000. Use 0, 1, 2, 3, 4, and 5 carpets as possible quantities. Put carpets on the horizontal axis and paintings on the vertical axis. b. Combining the information in the previous exercise with this exercise, use Excel to illustrate Lucy’s utility-maximizing solution given that her budget is $5,000, the price of a carpet is $1,000, and the price of a painting is $500. Appendix 4A The Marginal Rate of Substitution We can derive Equation 4.1 using calculus. Lisa’s utility function is U(B, Z). Along an indifference curve, we hold utility fixed at U = U(B, Z). If we increase Z, we would have to lower B to keep her on the same indifference curve. Let B(Z) be the implicit function that shows how much B it takes to keep Lisa’s utility at U given that she consumes Z. Thus, we can write her indifference curve as U = U(B(Z), Z), which is solely a function of Z. We want to know how much B must change if we increase Z, dB/dZ, given that we require her utility to remain constant by staying on the original indifference curve. To answer this question, we differentiate U = U(B(Z), Z) with respect to Z and set this derivative to zero because U is constant along an indifference curve. 0U(B(Z),Z) dB 0U(B(Z),Z) dU dB = 0 = + = MUB + MUZ. dZ 0B dZ 0Z dZ The partial derivatives show how utility changes as we change either B or Z holding the other constant. We know that dU/dZ = 0 because U is a constant along the indifference curve. Rearranging terms in this expression, we obtain Equation 4.1 (where dB/dZ replaces ΔB/ΔZ): MRS = dB/dZ = -MUZ/MUB. For example, the Cobb-Douglas utility function (named after its inventors) is U = BaZ1 - a. The marginal utilities are MUB = aBa - 1Z1 - a = aU/B and MUZ = (1 - a)BaZ -a = (1 - a)U/Z. Thus, MRS = - Appendix 4B (1 - a)U/Z (1 - a) B MUZ . = = a MUB aU/B Z (4A.1) The Consumer Optimum We can derive Equation 4.6 using calculus. Lisa’s objective is to maximize her utility, U(B, Z), subject to (s.t.) a budget constraint: max U(B,Z) B, Z s.t. Y = pBB + pZZ, (4B.1) where B is the number of burritos she buys at price pB, Z is the number of pizzas she buys at price pZ, Y is her income, and Y = pBB + pZZ is her budget constraint. This mathematical statement of her problem shows that her choice variables are B and Z, which appear under the “max” term in the equation. Because we cannot directly solve a constrained maximization problem, we want to convert Equation 4B.1 into an unconstrained problem by substituting the budget constraint into the utility function. Using algebra, we rearrange her budget constraint so that B is a function of Z: B(Z) = (Y - pZZ)/pB. Substituting this expression for B(Z) into the utility function, we rewrite her problem as 122 Appendix 4B The Consumer Optimum max U(B(Z), Z) = U ¢ Z Y - pzZ , Z≤. pB 123 (4B.2) Because Equation 4B.2 is unconstrained, we can use standard maximization techniques to solve it. We derive the first-order condition by setting the derivative of Lisa’s utility function with respect to Z equal to zero: pZ 0U pZ dU 0U dB 0U 0U = + = ¢- ≤ + = ¢ - ≤MUB + MUZ = 0, (4B.3) pB 0B pB dZ 0B dZ 0Z 0Z where MUB(B, Z) = 0U(B, Z)/0B. Rearranging the terms in Equation 4B.3, we obtain the condition in Equation 4.6 that her utility is maximized if the slope of the indifference curve, MRS, equals the slope of the budget line, MRT: MRS = - pZ MUZ = = MRT. pB MUB (4B.4) If the utility function is Cobb-Douglas, the MRS is given by Equation 4A.1, so Equation 4B.4 becomes MRS = or pZ (1 - a) B MUZ = - , = pB a MUB Z (1 - a)pZZ = apBB. (4B.5) Rearranging the budget constraint, pZZ = Y - pBB. Substituting Y - pBB for pZZ in Equation 4B.5, we obtain (1 - a)(Y - pBB) = apBB. Thus, B = aY/pB. Similarly, by substituting pBB = Y - pZZ in Equation 4B.5, we find that Z = (1 - a)/pZ. 5 M anagerial P roblem Labor Productivity During Recessions Production Hard work never killed anybody, but why take a chance? —Charlie McCarthy John Nelson, American Licorice Company’s Union City plant manager, invested $10 million in new labor-saving equipment, such as an automated drying machine. This new equipment allowed the company to cut its labor force from 450 to 240 workers. The factory produces 150,000 pounds of Red Vines licorice a day and about a tenth as much black licorice. The manufacturing process starts by combining flour and corn syrup (for red licorice) or molasses (for black licorice) to form a slurry in giant vats. The temperature is raised to 200° for several hours. Flavors are introduced and a dye is added for red licorice. Next the mixture is drained from the vats into barrels and cooled overnight, after which it is extruded through a machine to form long strands. Other machines punch an air hole through the center of the strands, after which the strands are twisted and cut. Then, the strands are dried in preparation for packaging. Food manufacturers are usually less affected by recessions than are firms in other industries. Nonetheless during major economic downturns, the demand curve for licorice may shift to the left, and Mr. Nelson must consider whether to reduce production by laying off some of his workers. He needs to decide how many workers to lay off. To make this decision, he faces a managerial problem: How much will the output produced per worker rise or fall with each additional layoff? T 124 his chapter looks at an important set of decisions that managers, such as those of American Licorice, have to face. First, the firm must decide how to produce licorice. American Licorice now uses relatively more machines and fewer workers than in the past. Second, if a firm wants to expand its output, it must decide how to do that in both the short run and the long run. In the short run, American Licorice can expand output by hiring extra workers or extending the workweek (more shifts per day or more workdays per week) and using extra materials. To expand output even more, American Licorice would have to install more equipment and eventually build a new plant, all of which take time. Third, given its ability to change its output 5.1 Production Functions 125 level, a firm must determine how large to grow. American Licorice determines how much to invest based on its expectations about future demand and costs. Firms and the managers who run them perform the fundamental economic function of producing output—the goods and services that consumers want. The main lesson of this chapter is that firms are not black boxes that mysteriously transform inputs (such as labor, capital, and materials) into outputs. Economic theory explains how firms make decisions about production processes, the types of inputs to use, and the volume of output to produce. M ain Topics 1. Production Functions: A production function summarizes how a firm converts inputs into outputs using one of possibly many available technologies. In this chapter, we examine five main topics 2. Short-Run Production: In the short run, only some inputs can be varied, so the firm changes its output by adjusting its variable inputs. 3. Long-Run Production: In the long run, all factors of production can be varied and the firm has more flexibility than in the short run in how it produces and how it changes its output level. 4. Returns to Scale: How the ratio of output to input varies with the size of the firm is an important factor in determining the size of a firm. 5. Productivity and Technological Change: Technological progress increases productivity: the amount of output that can be produced with a given amount of inputs. 5.1 Production Functions A firm uses a technology or production process to transform inputs or factors of production into outputs. Firms use many types of inputs. Most of these inputs can be grouped into three broad categories: ◗ Capital (K). Services provided by long-lived inputs such as land, buildings (such as factories and stores), and equipment (such as machines and trucks) ◗ Labor (L). Human services such as those provided by managers, skilled workers (such as architects, economists, engineers, and plumbers), and less-skilled workers (such as custodians, construction laborers, and assembly-line workers) ◗ Materials (M). Natural resources and raw goods (e.g., oil, water, and wheat) and processed products (e.g., aluminum, plastic, paper, and steel) The output can be a service, such as an automobile tune-up by a mechanic, or a physical product, such as a computer chip or a potato chip. Firms can transform inputs into outputs in many different ways. Companies that manufacture candy differ in the skills of their workforce and the amount of equipment they use. While all employ a chef, a manager, and some relatively unskilled workers, many candy firms also use skilled technicians and modern equipment. In small candy companies, the relatively unskilled workers shape the candy, decorate it, package it, and box it by hand. In slightly larger firms, relatively unskilled workers may use conveyor belts and other equipment that was invented decades ago. In modern, large-scale plants, the relatively unskilled laborers work with robots and other state-of-the-art machines, which are maintained by skilled technicians. Before deciding which production process to use, a firm needs to consider its various options. 126 CHAPTER 5 Production The various ways in which inputs can be transformed into output are summarized in the production function: the relationship between the quantities of inputs used and the maximum quantity of output that can be produced, given current knowledge about technology and organization. The production function for a firm that uses only labor and capital is q = f(L, K), (5.1) where q units of output (such as wrapped candy bars) are produced using L units of labor services (such as hours of work by assembly-line workers) and K units of capital (such as the number of conveyor belts). The production function shows only the maximum amount of output that can be produced from given levels of labor and capital, because the production function includes only efficient production processes. A firm engages in efficient production (achieves technological efficiency) if it cannot produce its current level of output with fewer inputs, given existing knowledge about technology and the organization of production. A profit-maximizing firm is not interested in production processes that are inefficient and waste inputs: Firms do not want to use two workers to do a job that can be done as well by one worker. A firm can more easily adjust its inputs in the long run than in the short run. Typically, a firm can vary the amount of materials and of relatively unskilled labor it uses comparatively quickly. However, it needs more time to find and hire skilled workers, order new equipment, or build a new manufacturing plant. The more time a firm has to adjust its inputs, the more factors of production it can alter. The short run is a period of time so brief that at least one factor of production cannot be varied practically. A factor that cannot be varied practically in the short run is called a fixed input. In contrast, a variable input is a factor of production whose quantity can be changed readily by the firm during the relevant time period. The long run is a lengthy enough period of time that all relevant inputs can be varied. In the long run, there are no fixed inputs—all factors of production are variable inputs. Suppose that a painting company’s customers all want the paint job on their homes to be finished by the end of the day. The firm could complete these projects on time if it had one fewer job. To complete all the jobs, it needs to use more inputs. Even if it wanted to do so, the firm does not have time to buy or rent an extra truck and buy another compressor to run a power sprayer; these inputs are fixed in the short run. To get the work done that afternoon, the firm uses the company’s one truck to pick up and drop off temporary workers, each equipped with only a brush and paint, at the last job. In the long run, however, the firm can adjust all its inputs. If the firm wants to paint more houses every day, it hires more full-time workers, gets a second truck, purchases more compressors to run the power sprayers, and uses a computer to keep track of all its projects. How long it takes for all inputs to be variable depends on the factors a firm uses. For a janitorial service whose only major input is workers, the short run is a brief period of time. In contrast, an automobile manufacturer may need several years to build a new manufacturing plant or to design and construct a new type of machine. A pistachio farmer needs the better part of a decade before newly planted trees yield a substantial crop of nuts. For many firms, materials and often labor are variable inputs over a month. However, labor is not always a variable input. Finding additional highly skilled workers may take substantial time. Similarly, capital may be a variable or fixed input. A firm can rent small capital assets (such as trucks or office furniture) quickly, but it may 5.2 Short-Run Production 127 take the firm years to obtain larger capital assets (buildings and large, specialized pieces of equipment). To illustrate the greater flexibility that a firm has in the long run than in the short run, we examine the production function in Equation 5.1, in which output is a function of only labor and capital. We look first at the short-run and then at the long-run production processes. 5.2 Short-Run Production The short run is a period in which there is at least one fixed input. Focusing on a production process in which capital and labor are the only inputs, we assume that capital is the fixed input and that labor is variable. The firm can therefore increase output only by increasing the amount of labor it uses. In the short run, the firm’s production function, Equation 5.1, becomes q = f(L, K), (5.2) where q is output, L is the amount of labor, and K is the firm’s fixed amount of capital. To illustrate the short-run production process, we consider a firm that assembles computers for a manufacturing firm that supplies it with the necessary parts, such as computer chips and disk drives. If the assembly firm wants to increase its output in the short run, it cannot do so by increasing its capital (eight workbenches fully equipped with tools, electronic probes, and other equipment for testing computers). However, it can increase output in the short run by hiring extra workers or paying current workers extra to work overtime. The Total Product Function The exact relationship between output or total product and labor can be illustrated by using a particular function, Equation 5.2, a table, or a figure. Table 5.1 shows the relationship between output and labor when a firm’s capital is fixed. The first column lists the fixed amount of capital: eight fully equipped workbenches. The second column shows how much of the variable input, labor, the firm uses. In this example, the labor input is measured by the number of workers, as all work the same number of hours. Total output—the number of computers assembled in a day—is listed in the third column. As the number of workers increases, total output first increases and then decreases. With zero workers, no computers are assembled. One worker with access to the firm’s equipment assembles five computers in a day. As the number of workers increases, so does output: 1 worker assembles 5 computers in a day, 2 workers assemble 18, 3 workers assemble 36, and so forth. The maximum number of computers that can be assembled with the capital on hand, however, is limited to 110 per day. That maximum can be produced with 10 or 11 workers. If the firm were to use 12 or more workers, the workers would get in each other’s way and production would be lower than with 11 workers. The dashed line in the table indicates that a firm would not use more than 11 workers, because it would be inefficient to do so. We can show how extra workers affect the total product by using two additional concepts: the marginal product of labor and the average product of labor. 128 CHAPTER 5 Production T A B L E 5 . 1 Total Product, Marginal Product, and Average Product of Labor with Fixed Capital Marginal Product of Labor, MPL = Δq/ΔL Labor, L Output, Total Product of Labor q 8 0 0 8 8 8 8 8 8 8 8 8 8 8 1 2 3 4 5 6 7 8 9 10 11 5 18 36 56 75 90 98 104 108 110 110 5 13 18 20 19 15 8 6 4 2 0 5 9 12 14 15 15 14 13 12 11 10 8 8 12 13 108 104 -2 -4 9 8 Capital, K Average Product of Labor, APL = q/L Labor is measured in workers per day. Capital is fixed at eight fully equipped workbenches. The Marginal Product of Labor Before deciding whether to employ more labor, a manager wants to determine how much an extra unit of labor, ΔL = 1, will increase output, Δq. That is, the manager wants to know the marginal product of labor (MPL): the change in total output resulting from using an extra unit of labor, holding other factors (capital) constant. If output changes by Δq when the amount of labor increases by ΔL, the change in output per unit of labor is MPL = Δq ΔL . As Table 5.1 shows, if the number of workers increases from 1 to 2, ΔL = 1, output rises by Δq = 13 = 18 - 5, so the marginal product of labor is 13. Using Calculus Calculating the Marginal Product of Labor The short-run production function, q = f(L, K ) can be written as solely a function of L because capital is fixed: q = g(L). The calculus definition of the marginal product of labor is the derivative of this production function with respect to labor: MPL = dg(L)/dL. In the long run, when both labor and capital are free to vary, the marginal product of labor is the partial derivative of the production function, Equation 5.1, q = f(L, K), with respect to labor: MPL = 0q 0L = 0 f(L,K) 0L . 5.2 Short-Run Production 129 We use the symbol 0q/0L instead of dq/dL to represent a partial derivative.1 We use partial derivatives when a function has more than one explanatory variable. Here, q is a function of both labor, L, and capital, K. To obtain a partial derivative with respect to one variable, say L, we differentiate as usual where we treat the other variables (here just K) as constants. Q&A 5.1 For a linear production function q = f(L, K) = 2L + K and a multiplicative production function q = LK, what are the short-run production functions given that capital is fixed at K = 100? What are the marginal products of labor for these short-run production functions? Answer 1. Obtain the short-run production functions by setting K = 100. The short-run linear production function is q = 2L + 100 and the short-run multiplicative function is q = L * 100 = 100L. 2. Determine the marginal products of labor by differentiating the short-run production functions with respect to labor. The marginal product of labor is MPL = d(2L + 100)/dL = 2 for the short-run linear production function and MPL = d(100L)/dL = 100 for the short-run multiplicative production function. The Average Product of Labor Before hiring extra workers, a manager may also want to know whether output will rise in proportion to this extra labor. To answer this question, the firm determines how extra labor affects the average product of labor (APL): the ratio of output to the amount of labor used to produce that output, APL = q L . Table 5.1 shows that 9 workers can assemble 108 computers a day, so the average product of labor for 9 workers is 12( = 108/9) computers a day. Ten workers can assemble 110 computers in a day, so the average product of labor for 10 workers is 11( = 110/10) computers. Thus, increasing the labor force from 9 to 10 workers lowers the average product per worker. Graphing the Product Curves Figure 5.1 and Table 5.1 show how output (total product), the average product of labor, and the marginal product of labor vary with the number of workers. (The figures are smooth curves because the firm can hire a “fraction of a worker” by 1Above, we defined the marginal product as the extra output due to a discrete change in labor, such as an additional worker or an extra hour of work. In contrast, the calculus definition of the marginal product—the partial derivative—is the rate of change of output with respect to the labor for a very small (infinitesimal) change in labor As a result, the numerical calculation of marginal products can differ slightly if derivatives rather than discrete changes are used. 130 CHAPTER 5 Production employing a worker for a fraction of a day.) The curve in panel a of Figure 5.1 shows how a change in labor affects the total product, which is the amount of output that can be produced by a given amount of labor. Output rises with labor until it reaches its maximum of 110 computers at 11 workers, point B; with extra workers, the number of computers assembled falls. Panel b of the figure shows how the average product of labor and marginal product of labor vary with the number of workers. We can line up the figures in panels a and b vertically because the units along the horizontal axes of both figures, F IG U RE 5. 1 Production Relationships with Variable Labor (a) The total product of labor curve shows how many computers, q, can be assembled with eight fully equipped workbenches and a varying number of workers, L, who work eight-hour days (see columns 2 and 3 in Table 5.1). Where extra workers reduce the number of computers assembled (beyond point B), the total product curve is a dashed line, which indicates that such production is inefficient and is thus not part of the production function. The slope of the line from the origin to point A is the average product of labor for six workers. (b) Where the marginal product of labor (MPL = Δq/ΔL, column 4 of Table 5.1) curve is above the average product of labor (APL = q/L, column 5 of Table 5.1) curve, the APL must rise. Similarly, if the MPL curve is below the APL curve, the APL must fall. Thus, the MPL curve intersects the APL curve at the peak of the APL curve, point b, where the firm uses 6 workers. Output, q, Units per day (a) B 110 90 A Slope of this line = 90/6 = 15 0 6 11 L, Workers per day (b) APL, MPL Total product 20 a 15 Average product, APL Marginal product, MPL 0 4 6 b 11 L, Workers per day 5.2 Short-Run Production 131 the number of workers per day, are the same. The vertical axes differ, however. The vertical axis is total product in panel a and the average or marginal product of labor—a measure of output per unit of labor—in panel b. The Effect of Extra Labor. In most production processes, the average product of labor first rises and then falls as labor increases. One reason the APL curve initially rises in Figure 5.1 is that it helps to have more than two hands when assembling a computer. One worker holds a part in place while another one bolts it down. As a result, output increases more than in proportion to labor, so the average product of labor rises. Doubling the number of workers from one to two more than doubles the output from 5 to 18 and causes the average product of labor to rise from 5 to 9, as Table 5.1 shows. Similarly, output may initially rise more than in proportion to labor because of greater specialization of activities. With greater specialization, workers are assigned to tasks at which they are particularly adept, and time is saved by not having workers move from task to task. As the number of workers rises further, however, output may not increase by as much per worker because workers might have to wait to use a particular piece of equipment or get in each other’s way. In Figure 5.1, as the number of workers exceeds 6, total output increases less than in proportion to labor, so the average product falls. If more than 11 workers are used, the total product curve falls with each extra worker as the crowding of workers gets worse. Because that much labor is not efficient, that section of the curve is drawn with a dashed line to indicate that it is not part of the production function, which includes only efficient combinations of labor and capital. Similarly, the dashed portions of the average and marginal product curves are irrelevant because no firm would hire additional workers if doing so meant that output would fall. Relationships Among Product Curves. The three curves are geometrically related. First we use panel b to illustrate the relationship between the average and marginal product of labor curves. Then we use panels a and b to show the relationship between the total product of labor curve and the other two curves. An extra hour of work increases the average product of labor if the marginal product of labor exceeds the average product. Similarly, if an extra hour of work generates less extra output than the average, the average product falls. Therefore, the average product rises with extra labor if the marginal product curve is above the average product curve, and the average product falls if the marginal product is below the average product curve. Consequently, the average product curve reaches its peak, point a in panel b of Figure 5.1, where the marginal product and average product are equal: where the curves cross. The geometric relationship between the total product curve and the average and marginal product curves is illustrated in panels a and b of Figure 5.1. We can determine the average product of labor using the total product of labor curve. The average product of labor for L workers equals the slope of a straight line from the origin to a point on the total product of labor curve for L workers in panel a. The slope of this line equals output divided by the number of workers, which is the definition of the average product of labor. For example, the slope of the straight line drawn from the origin to point A (L = 6, q = 90) is 15, which equals the “rise” of q = 90 divided by 132 CHAPTER 5 Production the “run” of L = 6. As panel b shows, the average product of labor for 6 workers at point a is 15. The marginal product of labor also has a geometric relationship to the total product curve. The slope of the total product curve at a given point equals the marginal product of labor. That is, the marginal product of labor equals the slope of a straight line that is tangent to the total output curve at a given point. For example, at point B in panel a where there are 11 workers, the line tangent to the total product curve is flat so the marginal product of labor is zero (point b in panel b): A little extra labor has no effect on output. The total product curve is upward sloping when there are fewer than 11 workers, so the marginal product of labor is positive. If the firm is foolish enough to hire more than 11 workers, the total product curve slopes downward (dashed line), so the MPL is negative: Extra workers lower output. When there are 6 workers, the average product of labor equals the marginal product of labor. The reason is that the line from the origin to point A in panel a is tangent to the total product curve, so the slope of that line, 15, is the marginal product of labor and the average product of labor at point a in panel b, which is the peak of the APL curve. The Law of Diminishing Marginal Returns Next to supply equals demand, the most commonly used economic phrase claims that there are diminishing marginal returns: If a firm keeps increasing an input, holding all other inputs and technology constant, the corresponding increases in output will eventually become smaller (diminish). As most observed production functions have this property, this pattern is often called the law of diminishing marginal returns. This law determines the shape of the marginal product of labor curves: if only one input is increased, the marginal product of that input will diminish eventually. In Table 5.1, if the firm goes from 1 to 2 workers, the marginal product of labor of the second worker is 13. If 1 or 2 more workers are used, the marginal product rises: The marginal product for the third worker is 18, and the marginal product for the fourth worker is 20. However, if the firm increases the number of workers beyond 4, the marginal product falls: The marginal product of a fifth worker is 19, and that of the sixth worker is 15. Beyond 4 workers, each extra worker adds less and less extra output, so the total product of labor curve rises by smaller increments. At 11 workers, the marginal product is zero. This diminishing return to extra labor might be due to crowding, as workers get in each other’s way. As the amount of labor used grows large enough, the marginal product curve approaches zero and the total product curve becomes nearly flat. Instead of referring to the law of diminishing marginal returns, some people talk about the law of diminishing returns—leaving out the word marginal. Making this change invites confusion as it is not clear if the phrase refers to marginal returns or total returns. If as labor increases the marginal returns fall but remain positive, the total return rises. In panel b of Figure 5.1, marginal returns start to diminish when the labor input exceeds 4 but total returns rise, as panel 1 shows, until the labor input exceeds 11, where the marginal returns become negative. A second common misinterpretation of this law is to claim that marginal products must fall as we increase an input without requiring that technology and other inputs stay constant. If we increase labor while simultaneously increasing other factors or adopting superior technologies, the marginal product of labor can continue to rise. 5.2 Short-Run Production Mini-Case Malthus and the Green Revolution 133 In 1798, Thomas Malthus—a clergyman and professor of political economy— predicted that (unchecked) population would grow more rapidly than food production because the quantity of land was fixed. The problem, he believed, was that the fixed amount of land would lead to a diminishing marginal product of labor, so output would rise less than in proportion to the increase in farm workers, possibly leading to widespread starvation and other “natural” checks on population such as disease and violent conflict. Brander and Taylor (1998) argue that such a disaster might have occurred on Easter Island about 500 years ago. Today the earth supports a population about seven times as large as when Malthus made his predictions. Why haven’t most of us starved to death? The answer is that a typical agricultural worker produces vastly more food today than was possible when Malthus was alive. The output of a U.S. farm worker today is more than double that of an average worker just 50 years ago. We do not see diminishing marginal returns to labor because the production function has changed due to substantial technological progress in agriculture and because farmers make greater use of other inputs such as fertilizers and capital. Two hundred years ago, most of the world’s population had to work in agriculture to feed themselves. Today, less than 2% of the U.S. population works in agriculture. Over the last century, food production grew substantially faster than the population in most developed countries. For example, since World War II, the U.S. population doubled but U.S. food production tripled. Of course, the risk of starvation is more severe in low-income countries than in the United States. Fortunately, agricultural production in these nations increased dramatically during the second half of the twentieth century, saving an estimated billion lives. This increased production was due to a set of innovations called the Green Revolution, which included development of drought- and insect-resistant crop varieties, improved irrigation, better use of fertilizer and pesticides, and improved equipment. Perhaps the most important single contributor to the Green Revolution was U.S. agronomist Norman Borlaug, who won the Nobel Peace Prize in 1970. However, as he noted in his Nobel Prize speech, superior science is not the complete answer to preventing starvation. A sound economic system and a stable political environment are also needed. Economic and political failures such as the breakdown of economic production and distribution systems due to wars have caused per capita food production to fall, resulting in widespread starvation and malnutrition in sub-Saharan Africa. According to the United Nations Food and Agriculture Organization, about 27% of the population of sub-Saharan Africa suffer from significant undernourishment along with more than 17% of the population in South Asia (India, Pakistan, Bangladesh, and nearby countries)—harming over 500 million people in these two regions alone. 134 CHAPTER 5 5.3 Production Long-Run Production We started our analysis of production functions by looking at a short-run production function in which one input, capital, was fixed, and the other, labor, was variable. In the long run, however, both of these inputs are variable. With both factors variable, a firm can usually produce a given level of output by using a great deal of labor and very little capital, a great deal of capital and very little labor, or moderate amounts of both. That is, the firm can substitute one input for another while continuing to produce the same level of output, in much the same way that a consumer can maintain a given level of utility by substituting one good for another. Typically, a firm can produce in a number of different ways, some of which require more labor than others. For example, a lumberyard can produce 200 planks an hour with 10 workers using hand saws, with 4 workers using handheld power saws, or with 2 workers using bench power saws. We illustrate a firm’s ability to substitute between inputs in Table 5.2, which shows the amount of output per day the firm produces with various combinations of labor per day and capital per day. The labor inputs are along the top of the table, and the capital inputs are in the first column. The table shows four combinations of labor and capital that the firm can use to produce 24 units of output (in bold numbers): The firm may employ (a) 1 worker and 6 units of capital, (b) 2 workers and 3 units of capital, (c) 3 workers and 2 units of capital, or (d) 6 workers and 1 unit of capital. Isoquants These four combinations of labor and capital are labeled a, b, c, and d on the “q = 24” curve in Figure 5.2. We call such a curve an isoquant, which is a curve that shows the efficient combinations of labor and capital that can produce the same (iso) level of output (quantity). The isoquant shows the smallest amounts of inputs that will produce a given amount of output. That is, if a firm reduced either input, it could not produce as much output. If the production function is q = f(L, K), then the equation for an isoquant where output is held constant at q is q = f(L, K). An isoquant shows the flexibility that a firm has in producing a given level of output. Figure 5.2 shows three isoquants corresponding to three levels of output. These isoquants are smooth curves because the firm can use fractional units of each input. T A BLE 5 .2 Output Produced with Two Variable Inputs Labor, L Capital, K 1 2 3 4 5 6 1 10 14 17 20 22 24 2 3 4 5 6 14 17 20 22 24 20 24 28 32 35 24 30 35 39 42 28 35 40 45 49 32 39 45 50 55 35 42 49 55 60 5.3 Long-Run Production 135 These isoquants show the combinations of labor and capital that produce 14, 24, or 35 units of output, q. Isoquants farther from the origin correspond to higher levels of output. Points a, b, c, and d are various combinations of labor and capital the firm can use to produce q = 24 units of output. If the firm holds capital constant at 2 and increases labor from 1 (point e on the q = 14 isoquant) to 3 (c), its output increases to q = 24 isoquant. If the firm then increases labor to 6 (f ), its output rises to q = 35. K, Units of capital per day F IG U RE 5. 2 A Family of Isoquants a 6 b 3 2 c e f q = 35 d 1 q = 24 q = 14 0 1 2 3 6 L, Workers per day We can use these isoquants to illustrate what happens in the short run when capital is fixed and only labor varies. As Table 5.2 shows, if capital is constant at 2 units, 1 worker produces 14 units of output (point e in Figure 5.2), 3 workers produce 24 units (point c), and 6 workers produce 35 units (point f ). Thus, if the firm holds one factor constant and varies another factor, it moves from one isoquant to another. In contrast, if the firm increases one input while lowering the other appropriately, the firm stays on a single isoquant. Properties of Isoquants. Isoquants have most of the same properties as indifference curves. The biggest difference between indifference curves and isoquants is that an isoquant holds quantity constant, whereas an indifference curve holds utility constant. We now discuss three major properties of isoquants. Most of these properties result from firms producing efficiently. First, the farther an isoquant is from the origin, the greater the level of output. That is, the more inputs a firm uses, the more output it gets if it produces efficiently. At point e in Figure 5.2, the firm is producing 14 units of output with 1 worker and 2 units of capital. If the firm holds capital constant and adds 2 more workers, it produces at point c. Point c must be on an isoquant with a higher level of output—here, 24 units—if the firm is producing efficiently and not wasting the extra labor. Second, isoquants do not cross. Such intersections are inconsistent with the requirement that the firm always produces efficiently. For example, if the q = 15 and q = 20 isoquants crossed, the firm could produce at either output level with the same combination of labor and capital. The firm must be producing inefficiently if it produces q = 15 when it could produce q = 20. So that labor-capital combination should not lie on the q = 15 isoquant, which should include only efficient combinations of inputs. Thus, efficiency requires that isoquants do not cross. Third, isoquants slope downward. If an isoquant sloped upward, the firm could produce the same level of output with relatively few inputs or relatively many CHAPTER 5 136 Production inputs. Producing with relatively many inputs would be inefficient. Consequently, because isoquants show only efficient production, an upward-sloping isoquant is impossible. Virtually the same argument can be used to show that isoquants must be thin. Shapes of Isoquants. The curvature of an isoquant shows how readily a firm can substitute one input for another. The two extreme cases are production processes in which inputs are perfect substitutes or in which they cannot be substituted for each other. If the inputs are perfect substitutes, each isoquant is a straight line. Suppose either potatoes from Maine, x, or potatoes from Idaho, y, both of which are measured in pounds per day, can be used to produce potato salad, q, measured in pounds. The production function is q = x + y. One pound of potato salad can be produced by using 1 pound of Idaho potatoes and no Maine potatoes, 1 pound of Maine potatoes and no Idaho potatoes, or any combination that adds up to 1 pound in total. Panel a of Figure 5.3 shows the q = 1, 2, and 3 isoquants. These isoquants are straight lines with a slope of -1 because we need to use an extra pound of Maine potatoes for every pound fewer of Idaho potatoes used.2 Sometimes it is impossible to substitute one input for the other: Inputs must be used in fixed proportions. Such a production function is called a fixed-proportions production function. For example, the inputs needed to produce 12-ounce boxes of F IG U RE 5. 3 Substitutability of Inputs (a) If inputs are perfect substitutes, each isoquant is a straight line. (b) If the inputs cannot be substituted at all, the isoquants are right angles (the dashed lines show that the isoquants would be right angles if we included (b) q=3 q=3 q=2 q=2 q=1 q=1 K, Capital per unit of time (c) Boxes per day y, Idaho potatoes per day (a) inefficient production). (c) Typical isoquants lie between the extreme cases of straight lines and right angles. Along a curved isoquant, the ability to substitute one input for another varies. q=1 45° line x, Maine potatoes per day Cereal per day L, Labor per unit of time 2The isoquant for q = 1 pound of potato salad is 1 = x + y, or y = 1 - x. This equation shows that the isoquant is a straight line with a slope of -1. 5.3 Long-Run Production 137 cereal are cereal (in 12-ounce units per day) and cardboard boxes (boxes per day). If the firm has one unit of cereal and one box, it can produce one box of cereal. If it has one unit of cereal and two boxes, it can still make only one box of cereal. Thus, in panel b, the only efficient points of production are the large dots along the 45° line.3 Dashed lines show that the isoquants would be right angles if isoquants could include inefficient production processes. Other production processes allow imperfect substitution between inputs. These processes have isoquants that are convex to the origin (so the middle of the isoquant is closer to the origin than it would be if the isoquant were a straight line). They do not have the same slope at every point, unlike the straight-line isoquants. Most isoquants are smooth, slope downward, curve away from the origin, and lie between the extreme cases of straight lines (perfect substitutes) and right angles (fixed proportions), as panel c illustrates. Mini-Case A Semiconductor Isoquant We can show why isoquants curve away from the origin by deriving an isoquant for semiconductor integrated circuits (ICs, or “chips”)—the “brains” of computers and other electronic devices. Semiconductor manufacturers buy silicon wafers and then use labor and capital to produce the chips. A chip consists of multiple layers of silicon wafers. A key step in the production process is to line up these layers. Three alternative alignment technologies are available, using different combinations of labor and capital. In the least capitalintensive technology, employees use machines called aligners, which require workers to look through microscopes and line up the layers by hand. A worker using an aligner can produce 25 ten-layer chips per day. A second, more capital-intensive technology uses machines called steppers. The stepper aligns the layers automatically. This technology requires less labor: A single worker can produce 50 ten-layer chips per day. A third, even more capital-intensive technology combines steppers with wafer-handling equipment, which further reduces the amount of labor needed. A single worker can produce 100 ten-layer chips per day. In the diagram the vertical axis measures the amount of capital used. An aligner represents less capital than a basic stepper, which in turn is less capital than a stepper with wafer-handling capabilities. All three technologies use labor and capital in fixed proportions. To produce 200 chips takes 8 workers and 8 aligners, 3 workers and 6 basic steppers, or 1 worker and 4 steppers with wafer-handling capabilities. The accompanying graph shows the three right-angle isoquants corresponding to each of these three technologies. Some plants employ a combination of these technologies, so that some workers use one type of machine while others use different types. By doing so, the plant can produce using intermediate combinations of labor and capital, as the solidline, kinked isoquant illustrates. The firm does not use a combination of the aligner and the wafer-handling stepper technologies because those combinations fixed-proportions production function is the minimum of g and b, q = min(g, b), where g is the number of 12-ounce measures of cereal, b is the number of boxes used in a day, and the min function means “the minimum number of g or b.” For example, if g is 4 and b is 3, q is 3. 3This K, Units of capital per day 138 CHAPTER 5 Production Wafer-handling stepper Stepper Aligner 200 ten-layer chips per day isoquant 0 1 3 8 L, Workers per day are less efficient than using the basic stepper: The line connecting the aligner and wafer-handling stepper technologies is farther from the origin than the lines between those technologies and the basic stepper technology. New processes are constantly being invented. As they are introduced, the isoquant will have more and more kinks (one for each new process) and will begin to resemble the smooth, convex isoquants we’ve been drawing. Substituting Inputs The slope of an isoquant shows the ability of a firm to replace one input with another while holding output constant. Figure 5.4 illustrates this substitution using an estimated isoquant for a U.S. printing firm, which uses labor, L, and capital, K, to print its output, q.4 The isoquant shows various combinations of L and K that the firm can use to produce 10 units of output. The firm can produce 10 units of output using the combination of inputs at a or b. At point a, the firm uses 2 workers and 16 units of capital. The firm could produce the same amount of output using ΔK = -6 fewer units of capital if it used one more worker, ΔL = 1, point b. If we drew a straight line from a to b, its slope would be ΔK/ΔL = -6. Thus, this slope tells us how many fewer units of capital (6) the firm can use if it hires one more worker.5 The slope of an isoquant is called the marginal rate of technical substitution (MRTS): MRTS = change in capital change in labor = ΔK . ΔL The marginal rate of technical substitution tells us how many units of capital the firm can replace with an extra unit of labor while holding output constant. Because isoquants slope downward, the MRTS is negative. That is, the firm can produce a given level of output by substituting more capital for less labor (or vice versa). isoquant for q = 10 is based on the estimated production function q = 2.35L0.5K0.4 (Hsieh, 1995), where the unit of labor, L, is a worker-day. Because capital, K, includes various types of machines, and output, q, reflects different types of printed matter, their units cannot be described by any common terms. This production function is an example of a Cobb-Douglas production function. 4This 5The slope of the isoquant at a point equals the slope of a straight line that is tangent to the isoquant at that point. Thus, the straight line between two nearby points on an isoquant has nearly the same slope as that of the isoquant. 5.3 Long-Run Production 139 Moving from point a to b, a U.S. printing firm (Hsieh, 1995) can produce the same amount of output, q = 10, using six fewer units of capital, ΔK = - 6, if it uses one more worker, ΔL = 1. Thus, its MRTS = ΔK/ΔL = - 6. Moving from point b to c, its MRTS is - 3. If it adds yet another worker, moving from c to d, its MRTS is - 2. Finally, if it moves from d to e, its MRTS is - 1. Thus, because the isoquant is convex to the origin, it exhibits a diminishing marginal rate of technical substitution. That is, each extra worker allows the firm to reduce capital by a smaller amount as the ratio of capital to labor falls. K, Units of capital per day FIGURE 5.4 How the Marginal Rate of Technical Substitution Varies Along an Isoquant a 16 ΔK = –6 b 10 ΔL = 1 –3 c 1 –2 1 7 5 4 d e –1 q = 10 1 0 1 2 3 4 5 6 7 8 9 10 L, Workers per day Substitutability of Inputs Varies Along an Isoquant. The MRTS varies along a curved isoquant, as in Figure 5.4. If the firm is initially at point a and it hires one more worker, the firm can give up 6 units of capital and yet remain on the same isoquant (at point b), so the MRTS is -6. If the firm hires another worker, the firm can reduce its capital by 3 units and stay on the same isoquant, moving from point b to c, so the MRTS is -3. This decline in the MRTS (in absolute value) along an isoquant as the firm increases labor illustrates a diminishing MRTS. The more labor and less capital the firm has, the harder it is to replace remaining capital with labor and the flatter the isoquant becomes. In the special case in which isoquants are straight lines, isoquants do not exhibit diminishing marginal rates of technical substitution because neither input becomes more valuable in the production process: The inputs remain perfect substitutes. Q&A 5.2 illustrates this result. Q& A 5.2 A manufacturer produces a container of potato salad using one pound of Idaho potatoes, one pound of Maine potatoes, or one pound of a mixture of the two types of potatoes. Does the marginal rate of technical substitution vary along the isoquant? What is the MRTS at each point along the isoquant? Answer 1. Determine the shape of the isoquant. As panel a of Figure 5.3 illustrates, the potato salad isoquants are straight lines because the two types of potatoes are perfect substitutes. 2. On the basis of the shape, conclude whether the MRTS is constant along the isoquant. Because the isoquant is a straight line, the slope is the same at every point, so the MRTS is constant. 3. Determine the MRTS at each point. Earlier, we showed that the slope of this isoquant was –1, so the MRTS is -1 at each point along the isoquant. That is, because the two inputs are perfect substitutes, 1 pound of Idaho potatoes can be replaced by 1 pound of Maine potatoes. 140 CHAPTER 5 Production Substitutability of Inputs and Marginal Products. The marginal rate of technical substitution is equal to the ratio of marginal products. Because the marginal product of labor, MPL = Δq/ΔL, is the increase in output per extra unit of labor, if the firm hires ΔL more workers, its output increases by MPL * ΔL. For example, if the MPL is 2 and the firm hires one extra worker, its output rises by 2 units. A decrease in capital alone causes output to fall by MPK * ΔK, where MPK = Δq/ΔK is the marginal product of capital—the output the firm loses from decreasing capital by one unit, holding all other factors fixed. To keep output constant, Δq = 0, this fall in output from reducing capital must exactly equal the increase in output from increasing labor: (MPL * ΔL) + (MPK * ΔK) = 0. Rearranging these terms, we find that - MPL ΔK = = MRTS. MPK ΔL (5.3) Thus the ratio of marginal products equals the MRTS (in absolute value). We can use Equation 5.3 to explain why marginal rates of technical substitution diminish as we move to the right along the isoquant in Figure 5.4. As we replace capital with labor (move down and to the right along the isoquant), the marginal product of capital increases—when there are few pieces of equipment per worker, each remaining piece is more useful—and the marginal product of labor falls, so the MRTS = -MPL/MPK falls in absolute value. Cobb-Douglas Production Functions. We can illustrate how to determine the MRTS for a particular production function, the Cobb-Douglas production function. It is named after its inventors, Charles W. Cobb, a mathematician, and Paul H. Douglas, an economist and U.S. Senator. Through empirical studies, economists have found that the production processes in a very large number of industries can be accurately summarized by the Cobb-Douglas production function, which is q = ALαKβ, (5.4) where A, α, and β are all positive constants. We used regression analysis to estimate the production function for the BlackBerry smartphone, which was the first major smartphone. 6 The estimated Cobb-Douglas production function is Q = 2.83L1.52K0.82. That is, A = 2.83, α = 1.52, and β = 0.82. The constants α and β determine the relationships between the marginal and average products of labor and capital (as we show in the following section, Using Calculus). The marginal product of labor is α times the average product of labor, APL = q/L. That is, MPL = αq/L = αAPL. By dividing both sides of the expression by APL, we find that α equals the ratio of the marginal product of labor to the average product of labor: α = MPL/APL. Similarly, the marginal product of capital is MPK = βq/K = βAPK, and β = MPK/APK. 6The data are from the annual and quarterly reports from 1999 through 2009 of Research In Motion (renamed BlackBerry in 2013), the company that manufactures BlackBerry phones. 5.4 Returns to Scale 141 The marginal rate of technical substitution along an isoquant that holds output fixed at q is MRTS = - αq/L MPL α K. = = MPK βq/K β L (5.5) For example, given the BlackBerry’s production function, Q = 2.83L1.52K0.82, its MPL = αAPL = 1.52APL, and its MRTS = -(1.52/0.82)K/L ≈ -1.85K/L. The MRTS tells the firm’s managers the rate at which they can substitute capital for labor without reducing output. Using Calculus Cobb-Douglas Marginal Products To obtain the marginal product of labor for the Cobb-Douglas production function, Equation 5.4, q = ALαKβ, we partially differentiate the production function with respect to labor, holding capital fixed: MPL = 0q 0L = αALα - 1Kβ = α q ALαKβ = α . L L We obtain the last equality by substituting q = ALαKβ. Similarly, we can derive the marginal product of capital by partially differentiating the production function with respect to K: MPK = 5.4 0q 0K = βALαKβ - 1 = β q ALαKβ = β . K K Returns to Scale So far, we have examined the effects of increasing one input while holding the other input constant (shifting from one isoquant to another) or decreasing the other input by an offsetting amount (moving along an isoquant). We now turn to the question of how much output changes if a firm increases all its inputs proportionately. The answer helps a firm determine its scale or size in the long run. In the long run, a firm can increase its output by building a second plant and staffing it with the same number of workers as in the first one. Whether the firm chooses to do so depends in part on whether its output increases less than in proportion, in proportion, or more than in proportion to its inputs. Constant, Increasing, and Decreasing Returns to Scale If, when all inputs are increased by a certain proportion, output increases by that same proportion, the production function is said to exhibit constant returns to scale (CRS). A firm’s production process, q = f(L, K), has constant returns to scale if, when 142 CHAPTER 5 Production the firm doubles its inputs—by, for example, building an identical second plant and using the same amount of labor and equipment as in the first plant—it doubles its output: f(2L, 2K) = 2f(L, K) = 2q. We can check whether the potato salad production function has constant returns to scale. If a firm uses x1 pounds of Idaho potatoes and y1 pounds of Maine potatoes, it produces q1 = x1 + y1 pounds of potato salad. If it doubles both inputs, using x2 = 2x1 Idaho and y2 = 2y1 Maine potatoes, it doubles its output: q2 = x2 + y2 = 2x1 + 2y1 = 2(x1 + y1) = 2q1. Thus, the potato salad production function exhibits constant returns to scale. If output rises more than in proportion to an equal proportional increase in all inputs, the production function is said to exhibit increasing returns to scale (IRS). A technology exhibits increasing returns to scale if doubling inputs more than doubles the output: f(2L, 2K) 7 2f(L, K) = 2q. Why might a production function have increasing returns to scale? One reason is that, although it could build a copy of its original small factory and double its output, the firm might be able to more than double its output by building a single large plant, thereby allowing for greater specialization of labor or capital. In the two smaller plants, workers have to perform many unrelated tasks such as operating, maintaining, and fixing the machines they use. In the large plant, some workers may specialize in maintaining and fixing machines, thereby increasing efficiency. Similarly, a firm may use specialized equipment in a large plant but not in a small one. If output rises less than in proportion to an equal proportional increase in all inputs, the production function exhibits decreasing returns to scale (DRS). A technology exhibits decreasing returns to scale if doubling inputs causes output to rise less than in proportion: f(2L, 2K) 6 2f(L, K) = 2q. One reason for decreasing returns to scale is that the difficulty of organizing, coordinating, and integrating activities increases with firm size. An owner may be able to manage one plant well but may have trouble running two plants. In some sense, the decreasing returns to scale stemming from the owner’s difficulties in running a larger firm may reflect our failure to take into account some factor such as management skills in our production function. If a firm increases various inputs but does not increase the management input in proportion, the “decreasing returns to scale” may occur because one of the inputs to production, management skills, is fixed. Another reason is that large teams of workers may not function as well as small teams, in which each individual takes greater personal responsibility. 5.4 Returns to Scale Q&A 5.3 143 Under what conditions does a Cobb-Douglas production function, Equation 5.4, q = ALαK β, exhibit decreasing, constant, or increasing returns to scale? Answer 1. Show how output changes if both inputs are doubled. If the firm initially uses L and K amounts of inputs it produces q1 = ALαKβ. After the firm doubles the amount of both labor and capital it uses, it produces q2 = A(2L)α(2K)β = 2α + βALαKβ = 2α + βq1. (5.6) That is, q2 is 2α + β times q1. If we define γ = α + β, then Equation 5.6 tells us that q2 = 2γq1. (5.7) Thus, if the inputs double, output increases by 2γ. 2. Give a rule for determining the returns to scale. If γ = 1, we know from Equation 5.7 that q2 = 21q1 = 2q1. That is, output doubles when the inputs double, so the Cobb-Douglas production function has constant returns to scale. If γ 6 1, then q2 = 2γq1 6 2q1 because 2γ 6 2 if γ 6 1. That is, when input doubles, output increases less than in proportion, so this Cobb-Douglas production function exhibits decreasing returns to scale. Finally, the Cobb-Douglas production function has increasing returns to scale if γ 7 1 so that q2 7 2q1. Thus, the rule for determining returns to scale for a Cobb-Douglas production function is that the returns to scale are decreasing if γ 6 1, constant if γ = 1, and increasing if γ 7 1. Comment: One interpretation of γ is that, as all inputs increase by 1%, output increases by γ%. Thus, for example, if γ = 1, a 1% increase in all inputs increases output by 1%. M ini-Case Returns to Scale in U.S. Manufacturing Increasing, constant, and decreasing returns to scale are commonly observed. The table shows estimates of Cobb-Douglas production functions and returns to scale for various U.S. manufacturing industries (based on Hsieh, 1995). Labor, α Capital, β Returns to Scale, γ=α + β Tobacco products 0.18 0.33 0.51 Food and kindred products 0.43 0.48 0.91 Transportation equipment 0.44 0.48 0.92 Apparel and other textile products 0.70 0.31 1.01 Furniture and fixtures 0.62 0.40 1.02 Electronics and other electric equipment 0.49 0.53 1.02 0.44 0.30 0.51 0.65 0.88 0.73 1.09 1.18 1.24 Decreasing Returns to Scale Constant Returns to Scale Increasing Returns to Scale Paper and allied products Petroleum and coal products Primary metal CHAPTER 5 144 Production K, Units of capital per year The table shows that the estimated returns to scale measure γ for a tobacco firm is γ = 0.51: A 1% increase in the inputs causes output to rise by 0.51%. Because output rises less than in proportion to the inputs, the tobacco production function exhibits decreasing returns to scale. In contrast, firms that manufacture primary metals have increasing returns to scale production functions, in which a 1% increase in all inputs causes output to rise by 1.24%. The accompanying graphs use isoquants to illustrate the returns to scale for the electronics, tobacco, and primary metal firms. We measure the units of labor, capital, and output so that, for all three firms, 100 units of labor and 100 units of capital produce 100 units of output on the q = 100 isoquant in the three panels. For the constant returns to scale electronics firm, panel a, if both labor and capital are doubled from 100 to 200 units, (a) Electronics and Equipment: Constant Returns to Scale output doubles to 200 ( = 100 * 21, multiplying 500 the original output by the rate of increase using Equation 5.7). 400 That same doubling of inputs causes output to rise to only 142 (≈ 100 * 20.51) for the tobacco firm, panel b. Because output rises less than in 300 proportion to inputs, the production function has decreasing returns to scale. If the primary 200 metal firm doubles its inputs, panel c, its output more than doubles, to 236 (≈ 100 * 21.24), q = 200 so the production function has increasing 100 returns to scale. q = 100 These graphs illustrate that the spacing of the isoquant determines the returns to scale. 0 100 200 300 400 500 The closer together the q = 100 and q = 200 L, Units of labor per year isoquants, the greater the returns to scale. (c) Primary Metal: Increasing Returns to Scale 500 400 q = 200 300 200 K, Units of capital per year K, Units of capital per year (b) Tobacco: Decreasing Returns to Scale 500 400 300 200 q = 142 100 q = 236 100 q = 200 q = 100 0 100 200 300 400 500 L, Units of labor per year 0 100 200 q = 100 300 400 500 L, Units of labor per year 5.4 Returns to Scale 145 Varying Returns to Scale When the production function is Cobb-Douglas, the returns to scale are the same at all levels of output. However, in other industries, a production function’s returns to scale may vary as the output level changes. A firm might, for example, have increasing returns to scale at low levels of output, constant returns to scale for some range of output, and decreasing returns to scale at higher levels of output. Many production functions have increasing returns to scale for small amounts of output, constant returns for moderate amounts of output, and decreasing returns for large amounts of output. When a firm is small, increasing labor and capital allows for gains from cooperation between workers and greater specialization of workers and equipment—returns to specialization—so there are increasing returns to scale. As the firm grows, returns to scale are eventually exhausted. There are no more returns to specialization, so the production process has constant returns to scale. If the firm continues to grow, the owner starts having difficulty managing everyone, so the firm suffers from decreasing returns to scale. We show such a pattern in Figure 5.5. Again, the spacing of the isoquants reflects the returns to scale. Initially, the firm has one worker and one piece of equipment, point a, and produces 1 unit of output on the q = 1 isoquant. If the firm doubles its inputs, it produces at b, where L = 2 and K = 2, which lies on the dashed line through the origin and point a. Output more than doubles to q = 3, so the production function exhibits increasing returns to scale in this range. Another doubling of inputs to c causes output to double to 6 units, so the production function has constant returns to scale in this range. Another doubling of inputs to d causes output to increase by only a third, to q = 8, so the production function has decreasing returns to scale in this range. The production function that corresponds to these isoquants exhibits varying returns to scale. Initially, the firm uses one worker and one unit of capital, point a. Point b has double the amount of labor and capital as does a. Similarly, c has double the inputs of b, and d has double the inputs of c. All these points lie along the dashed 45° line. The first time the inputs are doubled, a to b, output more than doubles from q = 1 to q = 3, so the production function has increasing returns to scale. The next doubling, b to c, causes a proportionate increase in output, constant returns to scale. At the last doubling, from c to d, the production function exhibits decreasing returns to scale. K, Units of capital per year F IG U RE 5. 5 Varying Scale Economies d 8 q=8 c → d: Decreasing returns to scale c 4 q=6 b 2 b → c: Constant returns to scale a 1 q=3 a → b: Increasing returns to scale q=1 0 1 2 4 8 L, Work hours per year 146 CHAPTER 5 Ma nagerial I mplication Small Is Beautiful 5.5 Production The industrial revolution of the late eighteenth century took advantage of economies of scale to revolutionize production. Since then, the pursuit of scale economies has driven firms to become larger and larger in most industries. However, a number of recent inventions may cause savvy managers to reverse this trend. Entrepreneurs and managers should consider whether new technologies make small-scale production economically attractive. One of the most striking of these inventions is three-dimensional (3D) printing, which may greatly reduce the advantages of long production runs. An employee gives instructions (essentially a blueprint) to a 3D printer, presses Print, and the machine builds the object from the ground up, either by depositing material from a nozzle, or by selectively solidifying a thin layer of plastic or metal dust using drops of glue or a tightly focused beam. The final product can be a machine part, a bicycle frame, or a work of art. This technology changes the relative positions of isoquants, potentially reducing dramatically the extent of increasing returns to scale and allowing small entrepreneurs to compete effectively with larger firms. It may also allow greater customization at little additional cost. Currently these machines work only with certain plastics, resins, and metals, and have a precision of around a tenth of a millimeter. Costs have fallen to the point where manufacturing using 3D printers is cost effective, and new uses seem virtually unlimited. For example, in 2012, scientists at the University of Glasgow demonstrated that 3D printing can be used to create existing and new chemical compounds and, in 2013, a Dutch architect announced plans for the first 3D printed building. Moreover, 3D printing may lead to increased innovation and specialization. Any shape that you can design on a computer can be printed. Managers should use this technology to experiment. Managers can produce small initial runs to determine the size of the market and consumers’ acceptance of the product. Based on information from early adopters, managers can determine if the market warrants further production and quickly modify designs to meet end-users’ desires. Productivity and Technological Change Progress was all right. Only it went on too long. —James Thurber Because firms may use different technologies and different methods of organizing production, the amount of output that one firm produces from a given amount of inputs may differ from that produced by another firm. Further, after a positive technological or managerial innovation, a firm can produce more from a given amount of inputs than it could previously. Relative Productivity Firms are not necessarily equally productive, in the sense that one firm might be able to produce more than another from a given amount of inputs. A firm may be more productive than others if its manager knows a better way to organize production or if it is the only firm with access to a new invention. Union-mandated work rules, government regulations, or other institutional restrictions that affect only some firms might also lower the relative productivity of those firms. 5.5 Productivity and Technological Change 147 Differences in productivity across markets may be due to differences in the degree of competition. In competitive markets, in which many firms can enter and exit the market easily, less productive firms lose money and are driven out of business, so the firms that are actually producing are equally productive. In a less competitive oligopoly market, with few firms and no possibility of entry by new firms, a less productive firm may be able to survive, so firms with varying levels of productivity are observed. Mini-Case U.S. Electric Generation Efficiency Prior to the mid-1990s, over 90% of the electricity was produced and sold to consumers by investor-owned utility monopolies that were subject to government regulation of the prices they charged. Beginning in the mid-1990s, some states mandated that electric production be restructured. In such a state, the utility monopoly was forced to sell its electric generation plants to several other firms. These new firms sell the electricity they generate to the utility monopoly, which delivers the electricity to final consumers. Because they expected these new electric generator firms to compete with each other, state legislators hoped that this increased competition would result in greater production efficiency. Fabrizio, Rose, and Wolfram (2007) found that, in anticipation of greater competition, the generation plant operators in states that had restructured had reduced their labor and nonfuel expenses by 3% to 5% (holding output constant) relative to investor-owned utility monopoly plants in states that did not restructure. When compared to plants run by government-owned or cooperatively owned utility monopolies that were not exposed to restructuring incentives, these gains were even greater: 6% in labor and 13% in nonfuel expenses. Innovation In its production process, a firm tries to use the best available technological and managerial knowledge. An advance in knowledge that allows more output to be produced with the same level of inputs is called technological progress. The invention of new products is a form of technological innovation. The use of robotic arms increases the number of automobiles produced with a given amount of labor and raw materials. Better management or organization of the production process similarly allows the firm to produce more output from given levels of inputs. Technological Progress. A technological innovation changes the production process. Last year a firm produced q1 = f(L, K) units of output using L units of labor services and K units of capital service. Due to a new invention that the firm uses, this year’s production function differs from last year’s, so the firm produces 10% more output with the same inputs: q2 = 1.1f(L, K). Flath (2011) estimated the annual rate of technical innovation in Japanese manufacturing firms to be 0.91% for electric copper, 0.87% for medicine, 0.33% for steel pipes and tubes, 0.19% for cement, and 0.08% for beer. 148 CHAPTER 5 Production This type of technological progress reflects neutral technical change, in which more output is produced using the same ratio of inputs. However, technological progress may be nonneutral. Rather than increasing output for a given mix of inputs, technological progress could be capital saving, where the firm can produce the same level of output as before using less capital and the same amount of other inputs. The American Licorice Company’s automated drying machinery in the Managerial Problem is an example of labor-saving technological progress. Alternatively, technological progress may be labor saving. Basker (2012) found that the introduction of barcode scanners in grocery stores increased the average product of labor by 4.5% on average across stores. Amazon bought Kiva Systems in 2012 with the intention of using its robots to move items in Amazon’s warehouses, partially replacing workers. Other robots help doctors perform surgery quicker and reduce patients’ recovery times. Organizational Change. Organizational changes may also alter the production function and increase the amount of output produced by a given amount of inputs. In the early 1900s, Henry Ford revolutionized mass production of automobiles through two organizational innovations. First, he introduced interchangeable parts, which cut the time required to install parts because workers no longer had to file or machine individually made parts to get them to fit. Second, Ford introduced a conveyor belt and an assembly line to his production process. Before this change, workers walked around the car, and each worker performed many assembly activities. In Ford’s plant, each worker specialized in a single activity such as attaching the right rear fender to the chassis. A conveyor belt moved the car at a constant speed from worker to worker along the assembly line. Because his workers gained proficiency from specializing in only a few activities and because the conveyor belts reduced the number of movements workers had to make, Ford could produce more automobiles with the same number of workers. These innovations reduced the ratio of labor to capital used. In 1908, the Ford Model T sold for $850, when rival vehicles sold for $2,000. By the early 1920s, Ford had increased production from fewer than a thousand cars per year to two million per year. M ini-Case Tata Nano’s Technical and Organizational Innovations In 2009, the automotive world was stunned when India’s new Tata Motors started selling the Nano, its tiny, fuel-efficient four-passenger car. With a base price of less than $2,500, it is by far the world’s least expensive car. The next cheapest car in India, the Maruti 800, sold for about $4,800. The Nano’s dramatically lower price is not the result of amazing new inventions; it is due to organizational innovations that led to simplifications and the use of less expensive materials and procedures. Although Tata Motors filed for 34 patents related to the design of the Nano (compared to the roughly 280 patents awarded to General Motors annually), most of these patents are for mundane items such as the two-cylinder engine’s balance shaft and the configuration of the transmission gears. Instead of relying on innovations, Tata reorganized both production and distribution to lower costs. It reduced manufacturing costs at every stage of the process with a no-frills design, decreased vehicle weight, and made other major production improvements. 5.5 Productivity and Technological Change 149 The Nano has a single windshield wiper, one side-view mirror, no power steering, a simplified door-opening lever, three nuts on the wheels instead of the customary four, and a trunk that does not open from the outside—it is accessed by folding down the rear seats. The Nano has smaller overall dimensions than the Maruti, but about 20% more seating capacity because of design decisions, such as putting the wheels at the extreme edges of the car. The Nano is much lighter than comparable models due to the reduced amount of steel, the use of lightweight steel, and the use of aluminum in the engine. The ribbed roof structure is not only a style element but also a strength structure, which is necessary because the design uses thin-gauge sheet metal. Because the engine is in the rear, the driveshaft doesn’t need complex joints as in a frontengine car with front-wheel drive. To cut costs further, the company reduced the number of tools needed to make the components and thereby increased the life of the dies used by three times the norm. In consultation with their suppliers, Tata’s engineers determined how many useful parts the design required, which helped them identify functions that could be integrated in parts. Tata’s plant can produce 250,000 Nanos per year and benefits from economies of scale. However, Tata’s major organizational innovation was its open distribution and remote assembly. The Nano’s modular design enables an experienced mechanic to assemble the car in a workshop. Therefore, Tata Motors can distribute a complete knock-down (CKD) kit to be assembled and serviced by local assembly hubs and entrepreneurs closer to consumers. The cost of transporting these kits, produced at a central manufacturing plant, is charged directly to the customer. This approach is expected to speed up the distribution process, particularly in the more remote locations of India. The car has been a great success, selling more than 8,500 cars in May 2012. Ma nagerial So l ution Labor Productivity During Recessions During a recession, a manager of the American Licorice Company has to reduce output and decides to lay off workers. Will the firm’s labor productivity— average product of labor—go up and improve the firm’s situation or go down and harm it? Layoffs have the positive effect of freeing up machines to be used by remaining workers. However, if layoffs force the remaining workers to perform a wide variety of tasks, the firm will lose the benefits from specialization. When there are many workers, the advantage of freeing up machines is important and increased multitasking is unlikely to be a problem. When there are only a few workers, freeing up more machines does not help much (some machines might stand idle some of the time), while multitasking becomes a more serious problem. Holding capital constant, a change in the number of workers affects a firm’s average product of labor. Labor productivity could rise or fall. For example, in panel b of Figure 5.1, the average product of labor rises up to 15 workers per day 150 CHAPTER 5 Production and then falls as the number of workers increases. The average product of labor falls if the firm has 6 or fewer workers and lays 1 off, but rises if the firm initially has 7 to 11 workers and lays off a worker. For some production functions, layoffs always raise labor productivity because the APL curve is downward sloping everywhere. For such a production function, the positive effect of freeing up capital always dominates any negative effect of layoffs on average product. For example, layoffs raise the APL for any Cobb-Douglas production function, q = ALαKβ, where α is less than one.7 All the estimated production functions listed in the “Returns to Scale in U.S. Manufacturing” Mini-Case have this property. Let’s return to our licorice manufacturer. According to Hsieh (1995), the Cobb-Douglas production function for food and kindred product plants is q = AL0.43K0.48, so α = 0.43 is less than one and the APL curve slopes downward at every quantity. We can illustrate how much the APL rises with a layoff for this particular production function. If A = 1 and L = K = 10 initially, then the firm’s output is q = 100.43 * 100.48 ≈ 8.13, and its average product of labor is APL = q/L ≈ 8.13/10 = 0.813. If the number of workers is reduced by one, then output falls to q = 90.43 * 100.48 ≈ 7.77, and the average product of labor rises to APL ≈ 7.77/9 ≈ 0.863. That is, a 10% reduction in labor causes output to fall by 4.4%, but causes the average product of labor to rise by 6.2%. The firm’s output falls less than 10% because each remaining worker is more productive. Until recently, most large Japanese firms did not lay off workers during downturns. Thus, in contrast to U.S. firms, their average product of labor fell during recessions because their output fell while labor remained constant. Similarly, European firms have 30% less employment volatility over time than do U.S. firms, at least in part because European firms that fire workers are subject to a tax (Veracierto, 2008). Consequently, with other factors held constant in the short run, recessions might be more damaging to the profit of a Japanese or European firm than to the profit of a comparable U.S. firm. However, retaining good workers over short-run downturns might be a good long-run policy. S U MMARY 1. Production Functions. A production function 2. Short-Run Production. A firm can vary all its summarizes how a firm combines inputs such as labor, capital, and materials to produce output using the current state of knowledge about technology and management. A production function shows how much output can be produced efficiently from various levels of inputs. A firm produces efficiently if it cannot produce its current level of output with less of any one input, holding other inputs constant. inputs in the long run but only some of them in the short run. In the short run, a firm cannot adjust the quantity of some inputs, such as capital. The firm varies its output in the short run by adjusting its variable inputs, such as labor. If all factors are fixed except labor, and a firm that was using very little labor increases its use of labor, its output may rise more than in proportion to the increase in labor because of greater specialization of workers. 7 For this Cobb-Douglas production function, the average product of labor is APL = q/L = ALαKβ/L = ALα - 1Kβ. By partially differentiating this expression with respect to labor, we find that the change in the APL as the amount of labor rises is 0APL/0L = (α - 1)ALα - 2Kβ, which is negative if α 6 1. Thus, as labor falls, the average product of labor rises. Questions Eventually, however, as more workers are hired, the workers get in each other’s way or must wait to share equipment, so output increases by smaller and smaller amounts. This latter phenomenon is described by the law of diminishing marginal returns: The marginal product of an input—the extra output from the last unit of input—eventually decreases as more of that input is used, holding other inputs fixed. 3. Long-Run Production. In the long run, when all inputs are variable, firms can substitute between inputs. An isoquant shows the combinations of inputs that can produce a given level of output. The marginal rate of technical substitution is the absolute value of the slope of the isoquant and indicates how easily the firm can substitute one factor of production for another. Usually, the more of one input the firm uses, the more difficult it is to substitute that input for another input. That is, there are diminishing marginal rates of technical substitution as the firm uses more of one input. 4. Returns to Scale. When a firm increases all inputs in proportion and its output increases by 151 the same proportion, the production process is said to exhibit constant returns to scale. If output increases less than in proportion to the increase in inputs, the production process has decreasing returns to scale; if it increases more than in proportion, it has increasing returns to scale. All three types of returns to scale are commonly seen in actual industries. Many production processes exhibit first increasing, then constant, and finally decreasing returns to scale as the size of the firm increases. 5. Productivity and Technological Change. Even if all firms in an industry produce efficiently given what they know and the institutional and other constraints they face, some firms may be more productive than others, producing more output from a given bundle of inputs. More productive firms may have access to managerial or technical innovations not available to its rivals. Technological progress allows a firm to produce a given level of output using less inputs than it did previously. Technological progress changes the production function. Q U E S T ION S All exercises are available on MyEconLab; * = answer at the back of this book. 1. Production Functions 1.1. What are the main types of capital, labor, and materials used to produce licorice? *1.2. Suppose that for the production function q = f(L, K), if L = 3 and K = 5 then q = 10. Is it possible that L = 3 and K = 6 also yields q = 10 for this production function? Why or why not? 1.3. Consider Boeing (a producer of jet aircraft), General Mills (a producer of breakfast cereals), and Wacky Jack’s (which claims to be the largest U.S. provider of singing telegrams). For which of these firms is the short run the longest period of time? For which is the long run the shortest? Explain. 2. Short-Run Production *2.1. If each extra worker produces an extra unit of output, how do the total product of labor, average product of labor, and marginal product of labor vary with labor? Plot these curves in a graph similar to Figure 5.1. 2.2. Each extra worker produces an extra unit of output up to six workers. As more workers are added, no additional output is produced. Draw the total product of labor, average product of labor, and marginal product of labor curves in a graph similar to Figure 5.1. *2.3. Suppose that the production function is q = L0.75K0.25. (Hint: See Q&A 5.1.) a. What is the average product of labor, holding capital fixed at K? b. What is the marginal product of labor? c. How is the marginal product of labor related to the average product of labor? 2.4. In the short run, a firm cannot vary its capital, K = 2, but can vary its labor, L. It produces output q. Explain why the firm will or will not experience diminishing marginal returns to labor in the short run if its production function is a. q = 10L + K. b. q = L0.5K0.5. 2.5. Based on the information in the Mini-Case “Malthus and the Green Revolution,” how did the average product of labor in food production change over time? 3. Long-Run Production 3.1. Why must isoquants be thin? 3.2. According to Card (2009), (a) workers with less than a high school education are perfect substitutes for those with a high school education, (b) “high school 152 CHAPTER 5 Production equivalent” and “college equivalent” workers are imperfect substitutes, and (c) within education groups, immigrants and natives are imperfect substitutes. For each of these comparisons, draw the isoquants for a production function that uses two types of workers. For example, in part (a), production is a function of workers with a high school diploma and workers with less education. *3.3. To produce a recorded DVD, q = 1, a firm uses one blank disk, D = 1, and the services of a recording machine, M = 1, for one hour. (Hint: See Q&A 5.2.) a. Draw the isoquants for this production function and explain its shape. b. What is the MRTS at each point along the isoquant corresponding to q = 100? c. Draw the total product, average product, and marginal product of labor curves (you will probably want to use two diagrams) for this production function. 3.4. The production function at Ginko’s Copy Shop is q = 1,000 * min(L, 3K), where q is the number of copies per hour, L is the number of workers, and K is the number of copy machines. As an example, if L = 4 and K = 1, then the minimum of L and 3K, min(L, 3K) = 3, and q = 3,000. a. Draw the isoquants for this production function. b. Draw the total product, average product, and marginal product of labor curves for this production function for some fixed level of capital. 3.5. Using the figure in the Mini-Case “A Semiconductor Isoquant,” show that as the firm employs additional fixed-proportion technologies, the firm’s overall isoquant approaches a smooth curve similar to that in panel c of Figure 5.3. *3.6. A laundry cleans white clothes using the production function q = B + 2G, where B is the number of cups of Clorox bleach, G is the number of cups of a generic bleach that is half as potent, and q is the basketfuls of clothes that are cleaned. Draw an isoquant for one basketful of clothes. What is the marginal product of B? What is the marginal rate of technical substitution at each point on an isoquant? *3.7. At L = 4, K = 4, the marginal product of labor is 2 and the marginal product of capital is 3. What is the marginal rate of technical substitution (MRTS)? 4. Returns to Scale 4.1. To speed relief to isolated South Asian communities that were devastated by the December 2004 tsunami, the U.S. government doubled the number of helicopters from 45 to 90 in early 2005. Navy admiral Thomas Fargo, head of the U.S. Pacific Command, was asked if doubling the number of helicopters would “produce twice as much [relief].” He predicted, “Maybe pretty close to twice as much.” (Vicky O’Hara, All Things Considered, National Public Radio, January 4, 2005, www.npr.org/dmg/ dmg .php?prgCode=ATC&showDate=04-Jan2005&segNum=10&NPRMediaPref=WM&ge tAd=1.) Identify the outputs and inputs and describe the production process. Is the admiral discussing a production process with nearly constant returns to scale, or is he referring to another property of the production process? *4.2. The production function for the automotive and parts industry is q = L0.27K0.16M 0.61, where M is energy and materials (based on Klein, 2003). What kind of returns to scale does this production function exhibit? What is the marginal product of materials? 4.3. Under what conditions do the following production functions exhibit decreasing, constant, or increasing returns to scale? (Hint: See Q&A 5.3.) a. q = L + K. b. q = L + LαKβ + K. 4.4. A production function has the property that f(xL, xK) = x2f(L, K) for any positive value of x. What kind of returns to scale does this production function exhibit? If the firm doubles L and K, show that the marginal product of labor and the marginal product of capital also double. *4.5. Show in a diagram that a production function can have diminishing marginal returns to a factor and constant returns to scale. 4.6. Is it possible that a firm’s production function exhibits increasing returns to scale while exhibiting diminishing marginal productivity of each of its inputs? To answer this question, calculate the marginal productivities of capital and labor for the production of electronics and equipment, tobacco, and primary metal using the information listed in the “Returns to Scale in U.S. Manufacturing” Mini-Case. *4.7. The BlackBerry production function indicated in the text is Q = 2.83L1.52K0.82. Epple et al. (2010) estimate that the production function for U.S. housing is q = 1.38L0.144M 0.856, where L is land and M is an aggregate of all other mobile, nonland factors, which we call materials. Haskel and Sadun (2012) estimate the production function for U.K. supermarkets is Q = L0.23K0.10M 0.66, where L is labor, K is capital, and M is materials. What kind of returns to scale do these production functions exhibit? 4.8. Michelle’s business produces ceramic cups using labor, clay, and a kiln. She produces cups using a fixed proportion of labor and clay, but regardless Questions of how many cups she produces, she uses only one kiln. She can manufacture 25 cups a day with one worker and 35 with two workers. Does her production process illustrate decreasing returns to scale or a diminishing marginal product of labor? What is the likely explanation for why output doesn’t increase proportionately with the number of workers? 4.9. Does it follow that because we observe that the average product of labor is higher for Firm 1 than for Firm 2, Firm 1 is more productive in the sense that it can produce more output from a given amount of inputs? Why? 5. Productivity and Technological Change *5.1. Firm 1 and Firm 2 use the same type of production function, but Firm 1 is only 90% as productive as Firm 2. That is, the production function of Firm 2 is q2 = f(L, K), and the production function of Firm 1 is q1 = 0.9f(L, K). At a particular level of inputs, how does the marginal product of labor differ between the firms? 5.2. In a manufacturing plant, workers use a specialized machine to produce belts. A new machine is invented that is laborsaving. With the new machine, the firm can use fewer workers and still produce the same number of belts as it did using the old machine. In the long run, both labor and capital (the machine) are variable. From what you know, what is the effect of this invention on the APL, MPL, and returns to scale? If you require more information to answer this question, specify what you need to know. 5.3. Until the mid-eighteenth century when spinning became mechanized, cotton was an expensive and relatively unimportant textile (Virginia Postrel, “What Separates Rich Nations from Poor Nations?” New York Times, January 1, 2004). Where it used to take a hand-spinner 50,000 hours to hand-spin 100 pounds of cotton, an operator of a 1760s-era handoperated cotton mule-spinning machine could produce 100 pounds of stronger thread in 300 hours. When the self-acting mule spinner automated the process after 1825, the time dropped to 135 hours, and cotton became an inexpensive, common cloth. In a figure, show how these technological changes affected isoquants. Explain briefly. 6. Managerial Problem 6.1. If a firm lays off workers during a recession, how will the firm’s marginal product of labor change? (Hint: See Figure 5.1.) 153 *6.2. During recessions, U.S. firms lay off a larger proportion of their workers than Japanese firms do. (It has been claimed that Japanese firms continue to produce at high levels and store the output or sell it at relatively low prices during the recession.) Assuming that the production function remains unchanged over a period that is long enough to include many recessions and expansions, would you expect the average product of labor to be higher in Japan or the United States? Why? 7. Spreadsheet Exercises 7.1. Labor, L, and capital, K, are the only inputs in each of the following production functions: a. q1 = (L + K)2. b. q2 = c. q3 = 1 2L + 2K 2 2. 1 20 + 2L + 2K 2 2. For each production function, use a spreadsheet to find the output associated with the following output combinations: L = 2, K = 2; L = 4, K = 4; and L = 8, K = 8. Determine whether each production function exhibits increasing returns to scale, decreasing returns to scale, constant returns to scale, or variable returns to scale over this range. 7.2. The Green Revolution (see the Mini-Case “Malthus and the Green Revolution”) was based in part on extensive experimentation. The following data illustrates the relationship between nitrogen fertilizer (in pounds of nitrogen) and the output of a particular type of wheat (in bushels). Each observation is based on one acre of land and all other relevant inputs to production (such as water, labor, and capital) are held constant. The fertilizer levels are 20, 40, 60, 80, 100, 120, 140, and 160, and the associated output levels are 47, 86, 107, 131, 136, 148, 149, and 142. a. Use Excel to estimate the short-run production function showing the relationship between fertilizer input and output. (Hint: As described in Chapter 3, use the Trendline option to regress output on fertilizer input. Try a linear function and try a quadratic function and determine which function fits the data better.) b. Does fertilizer exhibit the law of diminishing marginal returns? What is the largest amount of fertilizer that should ever be used, even if it is free? 6 Costs An economist is a person who, when invited to give a talk at a banquet, tells the audience there’s no such thing as a free lunch. M anagerial P roblem Technology Choice at Home Versus Abroad A manager of a semiconductor manufacturing firm, who can choose from many different production technologies, must determine whether the firm should use the same technology in its foreign plant that it uses in its domestic plant. U.S. semiconductor manufacturing firms have been moving much of their production abroad since 1961, when Fairchild Semiconductor built a plant in Hong Kong. According to the Semiconductor Industry Association, world-wide semiconductor billings from the Americas dropped from 66% in 1976, to 34% in 1998, and to 18% by April 2013. Firms are moving their production abroad because of lower taxes, lower labor costs, and capital grant benefits. Capital grants are funds provided by a foreign government to firms to induce them to produce in that country. Such grants can reduce the cost of owning and operating an overseas semiconductor fabrication facility by as much as 25% compared to the costs of a U.S.-based plant. The semiconductor manufacturer can produce a chip using sophisticated equipment and relatively few workers or many workers and less complex equipment. In the United States, firms use a relatively capital-intensive technology, because doing so minimizes their cost of producing a given level of output. Will that same technology be cost minimizing if they move their production abroad? A firm uses a two-step procedure to determine the most efficient way to produce a certain amount of output. First, the firm determines which production processes are technically efficient so that it can produce the desired level of output without any wasted or unnecessary inputs. As we saw in Chapter 5, the firm uses engineering and other information to determine its production function, which summarizes the many technically efficient production processes available. A firm’s production function shows the maximum output that can be produced with any specified combination of inputs or factors of production, such as labor, capital, energy, and materials. The firm’s second step is to pick from these technically efficient production processes the one that is also economically efficient, minimizing the cost of producing a specified output level.1 To determine which process minimizes its cost 154 1Similarly, economically efficient production implies that the quantity of output is maximized for any given level of cost. 6.1 The Nature of Costs 155 of production, the firm uses information about the production function and the cost of inputs. Managers and economists need to understand the relationship between costs of inputs and production to determine the least costly way to produce. By minimizing the cost of producing a given level of output, a firm can increase its profit. M ain Topics 1. The Nature of Costs: When considering the cost of a proposed action, a good manager takes account of foregone alternative opportunities. In this chapter, we examine five main topics 2. Short-Run Costs: To minimize costs in the short run, the firm adjusts its variable factors of production (such as labor), but cannot adjust its fixed factors (such as capital). 3. Long-Run Costs: In the long run, all inputs are variable because the firm has the time to adjust all its factors of production. 4. The Learning Curve: A firm might be able to lower its costs of production over time as its workers and managers learn from experience about how best to produce a particular product. 5. The Costs of Producing Multiple Goods: If the firm produces several goods simultaneously, the cost of each may depend on the quantities of all the goods produced. 6.1 The Nature of Costs Too caustic? To hell with the costs, we’ll make the picture anyway. —Samuel Goldwyn Making sound managerial decisions about investment and production requires information about the associated costs. Some cost information is provided in legally required financial accounting statements. However, such statements do not provide sufficient cost information for good decision making. Financial accounting statements correctly measure costs for tax purposes and to meet other legal requirements, but good managerial decisions require a different perspective on costs. To produce a particular amount of output, a firm incurs costs for the required inputs such as labor, capital, energy, and materials. A firm’s manager (or accountant) determines the cost of labor, energy, and materials by multiplying the price of the factor times the number of units used. If workers earn $20 per hour and the firm hires 100 hours of labor per day, then the firm’s cost of labor is $20 * 100 = $2,000 per day. The manager can easily calculate these explicit costs, which are its direct, out-of-pocket payments for inputs to its production process during a given time period. While calculating explicit costs is straightforward, some costs are implicit in that they reflect only a foregone opportunity rather than explicit, current expenditure. Properly taking account of foregone opportunities requires particularly careful attention when dealing with durable capital goods, as past expenditures for an input may be irrelevant to current cost calculations if that input has no current, alternative use. Opportunity Costs A fundamental principle of managerial decision making is that managers should focus on opportunity costs. The opportunity cost of a resource is the value of the best alternative use of that resource. Explicit costs are opportunity costs. If a firm 156 CHAPTER 6 Costs purchases an input in a market and uses that input immediately, the input’s opportunity cost is the amount the firm pays for it, the market price. After all, if the firm did not use the input in its production process, its best alternative would be to sell it to someone else at the market price. The concept of an opportunity cost becomes particularly useful when the firm uses an input that it cannot purchase in a market or that was purchased in a market in the past. A key example of such an opportunity cost is the value of a manager’s time. For example, Maoyong owns and manages a firm. He pays himself only a small monthly salary of $1,000 because he also receives the firm’s profit. However, Maoyong could work for another firm and earn $11,000 a month. Thus, the opportunity cost of his time is $11,000—from his best alternative use of his time—not the $1,000 he actually pays himself. A financial statement may not include such an opportunity cost, but Maoyong needs to take account of this opportunity cost to make decisions that maximize his profit. Suppose that the explicit cost of operating his firm is $40,000, including the rent for work space, the cost of materials, the wage payments to an employee, and the $1,000 a month he pays himself. The full, opportunity cost of the firm is $50,000, which includes the extra $10,000 in opportunity cost for Maoyong’s time beyond the $1,000 that he already pays himself. If his firm’s revenue is $49,000 per month and he considers only his explicit costs of $40,000, it appears that his firm makes a profit of $9,000. In contrast, if he takes account of the full opportunity cost of $50,000, his firm incurs a loss of $1,000. Another example of an opportunity cost is captured in the well-known phrase “There’s no such thing as a free lunch.” Suppose your parents come to town and offer to take you to lunch. Although they pay the explicit cost—the restaurant’s tab—for the lunch, you still incur the opportunity cost of your time. No doubt the best alternative use of your time is studying this textbook, but you could also consider working at a job for a wage or watching television as possible alternatives. In considering whether to accept the “free” lunch, you need to compare this true opportunity cost against the benefit of dining with your parents. Mini-Case The Opportunity Cost of an MBA During major economic downturns, do applications to MBA programs fall, hold steady, or take off like tech stocks during the first Internet bubble? Knowledge of opportunity costs helps us answer this question. The biggest cost of attending an MBA program is often the opportunity cost of giving up a well-paying job. Someone who leaves a job paying $6,000 per month to attend an MBA program is, in effect, incurring a $6,000 per month opportunity cost, in addition to the tuition and cost of textbooks (though this one is well worth the money). Thus, it is not surprising that MBA applications rise in bad economic times when outside opportunities decline. People thinking of going back to school face a reduced opportunity cost of entering an MBA program if they think they might be laid off or might not be promoted during an economic downturn. As Stacey Kole, deputy dean for the MBA program at the University of Chicago Graduate School of Business, observed, “When there’s a go-go economy, fewer people decide to go back to school. When things go south the opportunity cost of leaving work is lower.” 6.1 The Nature of Costs 157 In 2008, when U.S. unemployment rose sharply and the economy was in poor shape, the number of people seeking admission to MBA programs rose sharply. The number of applicants to MBA programs for the class of 2008–2009 increased over the previous year by 79% in the United States, 77% in the United Kingdom, and 69% in other European programs. Applicants increased substantially for 2009–2010 as well in Canada and Europe. However, as economic conditions improved, global applications fell in 2011 and were relatively unchanged in 2012. Q& A 6.1 Meredith’s firm has sent her to a conference for managers and paid her registration fee. Included in the registration fee is free admission to a class on how to price derivative securities, such as options. She is considering attending, but her most attractive alternative opportunity is to attend a talk at the same time by Warren Buffett on his investment strategies. She would be willing to pay $100 to hear his talk, and the cost of a ticket is $40. Given that attending either talk involves no other costs, what is Meredith’s opportunity cost of attending the derivatives talk? Answer To determine her opportunity cost, determine the benefit that Meredith would forego by attending the derivatives class. Because she incurs no additional fee to attend the derivatives talk, Meredith’s opportunity cost is the foregone benefit of hearing the Buffett speech. Because she values hearing the Buffett speech at $100, but only has to pay $40, her net benefit from hearing that talk is $60 (= $100 - $40). Thus, her opportunity cost of attending the derivatives talk is $60. Costs of Durable Inputs Determining the opportunity cost of capital such as land, buildings, or equipment is more complex than calculating the cost of inputs that are bought and used in the same period such as labor services, energy, or materials. Capital is a durable good: a product that is usable for a long period, perhaps for many years. Two problems may arise in measuring the cost of a firm’s capital. The first is how to allocate the initial purchase cost over time. The second is what to do if the value of the capital changes over time. We can avoid these two measurement problems if capital is rented instead of purchased. For example, suppose a firm can rent a small pick-up truck for $400 a month or buy it outright for $20,000. If the firm rents the truck, the rental payment is the relevant opportunity cost per month. The truck is rented month by month, so the firm does not have to worry about how to allocate the purchase cost of a truck over time. Moreover, the rental rate would adjust if the cost of trucks changes over time. Thus, if the firm can rent capital for short periods of time, it calculates the cost of this capital in the same way that it calculates the cost of nondurable inputs such as labor services or materials. The firm faces a more complicated problem in determining the opportunity cost of the truck if it purchases the truck. The firm’s accountant may expense the truck’s purchase price by treating the full $20,000 as a cost when the truck is purchased, or the accountant may amortize the cost by spreading the $20,000 over the life of the 158 CHAPTER 6 Costs truck, following rules set by an accounting organization or by a relevant government authority such as the Internal Revenue Service (IRS). A manager who wants to make sound decisions about operating the truck does not expense or amortize the truck using such rules. The firm’s opportunity cost of using the truck is the amount that the firm would earn if it rented the truck to others. Thus, even though the firm owns the truck, the manager should view the opportunity cost of this capital good as a rent per time period. If the value of an older truck is less than that of a newer one, the rental rate for the truck falls over time. If no rental market for trucks exists, we must determine the opportunity cost in another way. Suppose that the firm has two choices: It can choose not to buy the truck and keep the truck’s purchase price of $20,000, or it can use the truck for a year and sell it for $17,000 at the end of the year. If the firm did not purchase the truck it would deposit the $20,000 in a bank account that pays, for example, 2% per year, earning $400 in interest and therefore having $20,400 at the end of the year. Thus, the opportunity cost of capital of using the truck for a year is $20,400 - $17,000 = $3,400.2 This $3,400 opportunity cost equals the depreciation of the truck of $3,000 (= $20,000 - $17,000) plus the $400 in foregone interest that the firm could have earned over the year if the firm had invested the $20,000. The value of trucks, machines, and other equipment declines over time, leading to declining rental values and therefore to declining opportunity costs. In contrast, the value of some land, buildings, and other forms of capital may rise over time. To maximize its economic profit, a firm must properly measure the opportunity cost of a piece of capital even if its value rises over time. If a beauty parlor buys a building when similar buildings in that area rent for $1,000 per month, then the opportunity cost of using the building is $1,000 a month. If land values rise causing rents in the area to rise to $2,000 per month, the beauty parlor’s opportunity cost of its building rises to $2,000 per month. Sunk Costs An opportunity cost is not always easy to observe but should always be taken into account in deciding how much to produce. In contrast, a sunk cost—a past expenditure that cannot be recovered—though easily observed is not relevant to a manager when deciding how much to produce now. If an expenditure is sunk, it is not an opportunity cost. Nonetheless, a sunk cost paid for a specialized input should still be deducted from income before paying taxes even if that cost is sunk, and must therefore appear in financial accounts. If a firm buys a forklift for $25,000 and can resell it for the same price, then the expenditure is not sunk, and the opportunity cost of using the forklift is $25,000. If instead the firm buys a specialized piece of equipment for $25,000 and cannot resell it, then the original expenditure is a sunk cost—it cannot be recovered. Because this equipment has no alternative use—it cannot be resold—its opportunity cost is zero, and hence should not be included in the firm’s current cost calculations. If the specialized equipment that originally cost $25,000 can be resold for $10,000, then only $15,000 of the original expenditure is sunk, and the opportunity cost is $10,000. 2The firm would also pay for gasoline, insurance, and other operating costs, but these items would all be expensed as operating costs and would not appear in the firm’s accounts as capital costs. 6.2 Short-Run Costs Ma nagerial I mplication Ignoring Sunk Costs 6.2 159 A manager should ignore sunk costs when making current decisions. To see why, consider a firm that paid $300,000 for a parcel of land for which the market value has fallen to $200,000, which is the land’s current opportunity cost. The $100,000 difference between the $300,000 purchase price and the current market value of $200,000 is a sunk cost that has already been incurred and cannot be recovered. The land is worth $240,000 to the firm if it builds a plant on this parcel. Is it worth carrying out production on this land or should the land be sold for its market value of $200,000? A manager who uses the original purchase price in the decision-making process would falsely conclude that using the land for production will result in a $60,000 loss: the value to using the land of $240,000 minus the purchase price of $300,000. Instead, the firm should use the land because it is worth $40,000 more as a production facility than the firm’s next best alternative of selling the land for $200,000. Thus, the firm should use the land’s opportunity cost in making its decisions and ignore the land’s sunk cost. In short, “there’s no use crying over spilt milk.” Short-Run Costs When making short-run and long-run production and investment decisions, managers must take the relevant costs into account. As noted in Chapter 5, the short run is the period over which some inputs, such as labor, can be varied while other inputs, such as capital, are fixed. In contrast, in the long run, the firm can vary all its inputs. For simplicity in our graphs, we concentrate on firms that use only two inputs, labor and capital. We focus on the case in which labor is the only variable input in the short run, and both labor and capital are variable in the long run. However, we can generalize our analysis to examine a firm that uses any number of inputs. We start by examining various measures of cost and cost curves that can be used to analyze costs in both the short run and the long run. Then we show how the shapes of the short-run cost curves are related to the firm’s production function. Common Measures of Cost All firms use the same basic cost measures for making both short-run and long-run decisions. The measures should be based on inputs’ opportunity costs. Fixed Cost, Variable Cost, and Total Cost. A fixed cost (F) is a cost that does not vary with the level of output. Fixed costs, which include expenditures on land, office space, production facilities, and other overhead expenses, cannot be avoided by reducing output and must be incurred as long as the firm stays in business. Fixed costs are often sunk costs, but not always. For example, a restaurant rents space for $2,000 per month on a month-to-month lease. This rent does not vary with the number of meals served (its output level), so it is a fixed cost. Because the restaurant has already paid this month’s rent, this fixed cost is a sunk cost: the restaurant cannot get the $2,000 back even if it goes out of business. Next month, if the restaurant stays open, it will have to pay the fixed, $2,000 rent. If the restaurant has a month-to-month rental agreement, this fixed cost of $2,000 is an avoidable cost, not a CHAPTER 6 160 Costs sunk cost. The restaurant can shut down, cancel its rental agreement, and avoid paying this fixed cost. Therefore, in planning for next month, the restaurant should treat the $2,000 rent as a fixed cost but not as a sunk cost. Thus, the fixed cost of $2,000 per month is a fixed cost in both the short run (this month) and in the long run. However, it is a sunk cost only in the short run. A variable cost (VC) is a cost that changes as the quantity of output changes. Variable costs are the costs of variable inputs, which are inputs that the firm can adjust to alter its output level, such as labor and materials. A firm’s cost (or total cost), C, is the sum of a firm’s variable cost and fixed cost: C = VC + F. Because variable costs change as the output level changes, so does total cost. For example, in Table 6.1, if the fixed cost is F = $48 and the firm produces 5 units of output, its variable cost is VC = $100, so its total cost is C = $148. Average Cost. Firms use three average cost measures corresponding to fixed, variable, and total costs. The average fixed cost (AFC) is the fixed cost divided by the units of output produced: AFC = F/q. The average fixed cost falls as output rises because the fixed cost is spread over more units. The average fixed cost falls from $48 for 1 unit of output to $4 for 12 units of output in Table 6.1. The average variable cost (AVC), or variable cost per unit of output, is the variable cost divided by the units of output produced: AVC = VC/q. Because the variable TA B LE 6. 1 How Cost Varies with Output Output, q Fixed Cost, F Variable Marginal Average Fixed Cost, VC Total Cost, C Cost, MC Cost, AFC = F/q Average Variable Cost, AVC = VC/q Average Cost, AC = C/q 0 48 0 48 1 48 25 73 25 48 25 73 2 48 46 94 21 24 23 47 3 48 66 114 20 16 22 38 4 48 82 130 16 12 20.5 32.5 5 48 100 148 18 9.6 20 29.6 6 48 120 168 20 8 20 28 7 48 141 189 21 6.9 20.1 27 8 48 168 216 27 6 21 27 9 48 198 246 30 5.3 22 27.3 10 48 230 278 32 4.8 23 27.8 11 48 272 320 42 4.4 24.7 29.1 12 48 321 369 49 4.0 26.8 30.8 6.2 Short-Run Costs 161 cost increases with output, the average variable cost may either increase or decrease as output rises. In Table 6.1, the average variable cost is $25 at 1 unit, falls until it reaches a minimum of $20 at 6 units, and then rises. The average cost (AC)—or average total cost—is the total cost divided by the units of output produced: AC = C/q. Because total cost is C = VC + F, if we divide both sides of the equation by q, we find that average cost is the sum of the average fixed cost and the average variable cost: AC = C F VC = + = AFC + AVC. q q q In Table 6.1, because AFC falls with output and AVC eventually rises with output, average cost falls until output is 8 units and then rises. Marginal Cost. A firm’s marginal cost (MC) is the amount by which a firm’s cost changes if the firm produces one more unit of output. The marginal cost is MC = ΔC Δq where ΔC is the change in cost when the change in output, Δq, is 1 unit in Table 6.1. If the firm increases its output from 2 to 3 units (Δq = 1), its total cost rises from $94 to $114 so ΔC = $20. Thus its marginal cost is ΔC/Δq = $20. Because only variable cost changes with output, marginal cost also equals the change in variable cost from a one-unit increase in output: MC = ΔVC . Δq As the firm increases output from 2 to 3 units, its variable cost increases by ΔVC = $20 = $66 - $46, so its marginal cost is MC = ΔVC/Δq = $20. A firm takes account of its marginal cost curve to decide whether it pays to change its output level. Using Calculus Calculating Marginal Cost Using calculus, we may alternatively define the marginal cost as MC = dC/dq, which is the rate of change of cost as we make an infinitesimally small change in output. Because C = VC + F, it follows that MC = dVC/dq + dF/dq = dVC/dq, because fixed costs do not change as output changes: dF/dq = 0. For example, suppose that the variable cost is VC = 4q + 6q2 and the fixed cost is F = 10, so the total cost is C = VC + F = 4q + 6q2 + 10. Using the variable cost, the marginal cost is dVC/dq = d(4q + 6q2)/dq = 4 + 12q. We get the same expression for marginal cost if we use the total cost: dC/dq = d(4q + 6q2 + 10)/dq = 4 + 12q. Cost Curves We illustrate the relationship between output and the various cost measures in Figure 6.1. Panel a shows the variable cost, fixed cost, and total cost curves that correspond to Table 6.1. The fixed cost, which does not vary with output, is a horizontal line at $48. The variable cost curve is zero at zero units of output and rises with 162 CHAPTER 6 Costs F IG U RE 6. 1 Cost Curves (a) Cost, $ (a) Because the total cost differs from the variable cost by the fixed cost, F, of $48, the total cost curve, C, is parallel to the variable cost curve, VC. (b) The marginal cost curve, MC, cuts the average variable cost, AVC, and average cost, AC, curves at their minimums. The height of the AC curve at point a equals the slope of the line from the origin to the cost curve at A. The height of the AVC at b equals the slope of the line from the origin to the variable cost curve at B. The height of the marginal cost is the slope of either the C or VC curve at that quantity. 400 C VC 27 A 216 1 20 1 B 120 48 0 F 2 4 6 Cost per unit, $ (b) 8 10 Quantity, q, Units per day 60 MC 28 27 a AC AVC b 20 8 AFC 0 2 4 6 10 8 Quantity, q, Units per day output. The total cost curve, which is the vertical sum of the variable cost curve and the fixed cost line, is $48 higher than the variable cost curve at every output level, so the variable cost and total cost curves are parallel. Panel b shows the average fixed cost, average variable cost, average cost, and marginal cost curves. The average fixed cost curve falls as output increases. It approaches zero as output gets large because the fixed cost is spread over many units of output. The average cost curve is the vertical sum of the average fixed cost and average variable cost curves. For example, at 6 units of output, the average variable cost is 20 and the average fixed cost is 8, so the average (total) cost is 28. The relationships between the average and marginal cost curves and the total cost curve are similar to those between the average and marginal product curves and the total product curve (as discussed in Chapter 5). The average cost at a particular 6.2 Short-Run Costs 163 output level is the slope of a line from the origin to the corresponding point on the total cost curve. The slope of that line is the rise (the cost at that output level) divided by the run (the output level), which is the definition of the average cost. In panel a, the slope of the line from the origin to point A is the average cost for 8 units of output. The height of the cost curve at A is 216, so the slope is 216/8 = 27, which is the height of the average cost curve at the corresponding point a in panel b. Similarly, the average variable cost is the slope of a line from the origin to a point on the variable cost curve. The slope of the dashed line from the origin to B in panel a is 20 (the height of the variable cost curve, 120, divided by the number of units of output, 6), which is also the height of the average variable cost curve at 6 units of output, point b in panel b. The marginal cost is the slope of either the cost curve or the variable cost curve at a given output level. Because the total cost and variable cost curves are parallel, they have the same slope at any given output. The difference between total cost and variable cost is fixed cost, which does not affect marginal cost. The thin black line from the origin is tangent to the cost curve at A in panel a. Thus, the slope of the thin black line equals both the average cost and the marginal cost at point a (8 units of output). This equality occurs at the corresponding point a in panel b, where the marginal cost curve intersects the average cost. Where the marginal cost curve is below the average cost, the average cost curve declines with output. Because the average cost of 47 for 2 units is greater than the marginal cost of the third unit, 20, the average cost for 3 units falls to 38.3 Where the marginal cost is above the average cost, the average cost curve rises with output. At 8 units, the marginal cost equals the average cost (at point a in panel b, the minimum point of the average cost curve), so the average is unchanging. Because the dashed line from the origin is tangent to the variable cost curve at B in panel a, the marginal cost equals the average variable cost at the corresponding point b in panel b. Again, where marginal cost is above average variable cost, the average variable cost curve rises with output; where marginal cost is below average variable cost, the average variable cost curve falls with output. Because the average cost curve is above the average variable cost curve everywhere and the marginal cost curve is rising where it crosses both average curves, the minimum of the average variable cost curve, b, is at a lower output level than the minimum of the average cost curve, a. Production Functions and the Shapes of Cost Curves The production function determines the shape of a firm’s cost curves. The production function shows the amount of inputs needed to produce a given level of output (Chapter 5). The firm calculates its variable cost by multiplying the quantity of each input by its price and summing the costs of the variable inputs. In this section, we focus on cost curves in the short run. If a firm produces output using capital and labor, and its capital is fixed in the short run, the firm’s variable cost is its cost of labor. Its labor cost is the wage per hour, w, times the number of hours of labor, L, employed by the firm: VC = wL. In the short run, when the firm’s capital is fixed, the only way the firm can increase its output is to use more labor. If the firm increases its labor enough, it reaches the 3From Table 6.1, we know that the average cost of the first two units is 47. If we add a third unit with a marginal cost of 20, the new average can be calculated by adding the average values of the first two units plus the marginal cost of the third unit and dividing by 3: (47 + 47 + 20)/3 = 38. Thus, if we add a marginal cost that is less than the old average cost, the new average cost must fall. 164 CHAPTER 6 Costs point of diminishing marginal returns to labor, at which each extra worker increases output by a smaller amount. We can use this information about the relationship between labor and output—the production function—to determine the shape of the variable cost curve and its related curves. The Variable Cost Curve. If input prices are constant, the firm’s production function determines the shape of the variable cost curve. We illustrate this relationship in Figure 6.2. The firm faces a constant input price for labor, the wage, of $10 per hour. The total product of labor curve in Figure 6.2 shows the firm’s short-run production function relationship between output and labor when capital is held fixed. At point a, the firm uses 5 hours of labor to produce 1 unit of output. At point b, it takes 20 hours of labor to produce 5 units of output. Here, output increases more than in proportion to labor: Output rises 5 times when labor increases 4 times. In contrast, as the firm moves from b to c, output increases less than in proportion. Output doubles to 10 as a result of increasing labor from 20 to 46—an increase of 2.3 times. The movement from c to d results in even a smaller increase in output relative to labor. This flattening of the total product curve at higher levels of labor reflects diminishing marginal returns to labor. This curve shows both the production relation of output to labor and the variable cost relation of output to cost. Because each hour of work costs the firm $10, we can relabel the horizontal axis in Figure 6.2 to show the firm’s variable cost, its cost of labor. To produce 5 units of output takes 20 hours of labor, so the firm’s variable cost F IG U RE 6. 2 Variable Cost and Total Product Quantity, q, Units per day The firm’s short-run variable cost curve and its total product curve have the same shape. The total product curve uses the horizontal axis measuring hours of work. The variable cost curve uses the horizontal axis measuring labor cost, which is the only variable cost. d 13 Total product, Variable cost c 10 b 5 1 0 a 5 50 20 200 46 460 77 770 L, Hours of labor per day VC = wL, Variable cost, $ 6.2 Short-Run Costs 165 is $200. By using the variable cost labels on the horizontal axis, the total product of labor curve becomes the variable cost curve. As output increases, the variable cost increases more than proportionally due to the diminishing marginal returns. Because the production function determines the shape of the variable cost curve, it also determines the shape of the marginal, average variable, and average cost curves. We now examine the shape of each of these cost curves in detail, because when making decisions, managers rely more on these per-unit cost measures than on total variable cost. The Marginal Cost Curve. The marginal cost is the change in variable cost as output increases by one unit: MC = ΔVC/Δq. In the short run, capital is fixed, so the only way the firm can produce more output is to use extra labor. The extra labor required to produce one more unit of output is ΔL/Δq. The extra labor costs the firm w per unit, so the firm’s cost rises by w(ΔL/Δq). As a result, the firm’s marginal cost is MC = ΔVC ΔL . = w Δq Δq The marginal cost equals the wage times the extra labor necessary to produce one more unit of output. To increase output by one unit from 5 to 6 units takes 4 extra hours of work in Figure 6.2. If the wage is $10 per hour, the marginal cost is $40. How do we know how much extra labor we need to produce one more unit of output? That information comes from the production function. The marginal product of labor—the amount of extra output produced by another unit of labor, holding other inputs fixed—is MPL = Δq/ΔL. Thus, the extra labor we need to produce one more unit of output, ΔL/Δq, is 1/MPL, so the firm’s marginal cost is MC = w . MPL (6.1) Equation 6.1 says that the marginal cost equals the wage divided by the marginal product of labor. If the firm is producing 5 units of output, it takes 4 extra hours of labor to produce 1 more unit of output in Figure 6.2, so the marginal product of an hour of labor is 14 unit of output. Given a wage of $10 an hour, the marginal cost of the sixth unit is $10 divided by 14, or $40. Equation 6.1 shows that the marginal product of labor and marginal cost move in opposite directions as output changes. At low levels of labor, the marginal product of labor commonly rises with additional labor because extra workers help the original workers and they can collectively make better use of the firm’s equipment. As the marginal product of labor rises, the marginal cost falls. Eventually, however, as the number of workers increases, workers must share the fixed amount of equipment and may get in each other’s way. As more workers are added, the marginal product of each additional worker begins to fall and the marginal cost of each additional unit of product rises. As a result, the marginal cost curve slopes upward because of diminishing marginal returns to labor. Thus, the marginal cost first falls and then rises. The Average Cost Curves. Because they determine the shape of the variable cost curve, diminishing marginal returns to labor also determine the shape of the average variable cost curve. The average variable cost is the variable cost divided 166 CHAPTER 6 Costs by output: AVC = VC/q. For the firm we’ve been examining, whose only variable input is labor, variable cost is wL, so average variable cost is AVC = VC wL . = q q Because the average product of labor, APL, is q/L, average variable cost is the wage divided by the average product of labor: AVC = w . APL (6.2) In Figure 6.2, at 6 units of output, the average product of labor is 14 (= q/L = 6/24), so the average variable cost is $40, which is the wage, $10, divided by the average product of labor, 14. With a constant wage, the average variable cost moves in the opposite direction of the average product of labor in Equation 6.2. As we discussed in Chapter 5, the average product of labor tends to rise and then fall, so the average cost tends to fall and then rise, as in panel b of Figure 6.1. The average cost curve is the vertical sum of the average variable cost curve and the average fixed cost curve, as in panel b of Figure 6.1. If the average variable cost curve is U-shaped, adding the strictly falling average fixed cost makes the average cost fall more steeply than the average variable cost curve at low output levels. At high output levels, the average cost and average variable cost curves differ by ever smaller amounts, as the average fixed cost, F/q, approaches zero. Thus, the average cost curve is also U-shaped. Using Calculus Calculating Cost Curves If we know the production function for a product (Chapter 5) and the factor prices, we can use math to derive the various cost functions. Based on the estimates of Flath (2011), the Cobb-Douglas production function of a typical Japanese beer manufacturer (Chapter 5) is q = 1.52L0.6K0.4, where labor, L, is measured in hours, K is the number of units of capital, and q is the amount of output. We assume that the firm’s capital is fixed at K = 100 units in the short run. If the rental rate of a unit of capital is $8, the fixed cost, F, is $800, the average fixed cost is AFC = F/q = 800/q, which falls as output increases. We can use the production function to derive the variable cost. Given that capital is fixed in the short run, the short-run production function is solely a function of labor: q = 1.52L0.61000.4 ≈ 9.59L0.6. Costs per unit, $ 6.2 Short-Run Costs Rearranging this expression, we can write the number of workers, L, needed to produce q units of output as a function solely of output: 50 MC 40 30 L(q) = ¢ AC AVC q 9.59 ≤ 1 0.6 = ¢ 1 1.67 1.67 ≤ q 9.59 ≈ 0.023q1.67. 20 AFC 100 200 (6.3) Now that we know how labor and output are related, we can calculate variable cost directly. The only variable input is labor, so if the wage is $24, the firm’s variable cost is VC(q) = wL(q) = 24L(q). (6.4) 10 0 167 300 q, Units per year Substituting for L(q) using Equation 6.3 into the variable cost Equation 6.4, we see how variable cost varies with output: VC(q) = 24L(q) = 24(0.023q1.67) ≈ 0.55q1.67. (6.5) Using this expression for variable cost, we can construct the other cost measures. To obtain the equation for marginal cost as a function of output, we differentiate the variable cost, VC(q), with respect to output: MC(q) = dVC(q) dq ≈ d(0.55q1.67) dq = 1.67 * 0.55q0.67 ≈ 0.92q0.67. We can also calculate total cost, C = F + VC, average cost, AC = C/q, and average variable cost, AVC = VC/q using algebra. The figure plots the beer firm’s AFC, AVC, AC, and MC curves. Short-Run Cost Summary We use cost curves to illustrate three cost level concepts—total cost, fixed cost, and variable cost—and four cost-per-unit cost concepts—average cost, average fixed cost, average variable cost, and marginal cost. Understanding the shapes of these curves and the relationships among them is crucial to the analysis of firm behavior in the rest of this book. Fortunately, we can derive most of what we need to know about the shapes and the relationships between the short-run curves using four basic concepts: 1. In the short run, the cost associated with inputs that cannot be adjusted is fixed, while the cost from inputs that can be adjusted is variable. 2. Given that input prices are constant, the shapes of the variable cost and the costper-unit curves are determined by the production function. 3. Where a variable input exhibits diminishing marginal returns, the variable cost and cost curves become relatively steep as output increases, so the average cost, average variable cost, and marginal cost curves rise with output. 168 CHAPTER 6 Costs 4. Because of the relationship between marginal values and average values, both the average cost and average variable cost curves fall when marginal cost is below them and rise when marginal cost is above them, so the marginal cost cuts both these average cost curves at their minimum points. 6.3 Long-Run Costs In the long run, the firm adjusts all its inputs so that its cost of production is as low as possible. The firm can change its plant size, design and build new machines, and otherwise adjust inputs that were fixed in the short run. Although firms may incur fixed costs in the long run, these fixed costs are avoidable (rather than sunk, as they are in the short run). The rent of F per month that a restaurant pays is a fixed cost because it does not vary with the number of meals (output) served. In the short run, this fixed cost is sunk: The firm must pay F even if the restaurant does not operate. In the long run, this fixed cost is avoidable because the restaurant need not renew its rental agreement. The firm does not have to pay this rent if it shuts down. This cost is still a fixed cost, even in the long run, but it is not sunk in the long run. To simplify our long-run analysis, we use examples with no long-run fixed costs (F = 0). Consequently, average cost and average variable cost are identical. To produce a given quantity of output at minimum cost, our firm uses information about its production function and the price of labor and capital. In the long run when capital is variable, the firm chooses how much labor and capital to use; in the short run when capital is fixed, the firm chooses only how much labor to use. As a consequence, the firm’s long-run cost of production is lower than its short-run cost if it has to use the “wrong” level of capital in the short run. In this section, we show how a firm picks the cost-minimizing combination of inputs in the long run. Input Choice A firm can produce a given level of output using many different technically efficient combinations of inputs, as summarized by an isoquant (Chapter 5). From among the technically efficient combinations of inputs that can be used to produce a given level of output, a firm wants to choose that bundle of inputs with the lowest cost of production, which is the economically efficient combination of inputs. To do so, the firm combines information about technology from the isoquant with information about the cost of production. The Isocost Line. The cost of producing a given level of output depends on the price of labor and capital. The firm hires L hours of labor services at a constant wage of w per hour, so its labor cost is wL. The firm rents K hours of machine services at a constant rental rate of r per hour, so its capital cost is rK. (If the firm owns the capital, r is the implicit rental rate.) The firm’s total cost is the sum of its labor and capital costs: C = wL + rK. (6.6) A firm can hire as much labor and capital as it wants at these constant input prices from competitive labor and capital markets. The firm can use many combinations of labor and capital that cost the same amount. Suppose that the wage rate, w, is $10 an hour and the rental rate of capital, r, is $20. Five of the many combinations of labor and capital that the firm can use that 6.3 Long-Run Costs 169 T A BLE 6 .2 Bundles of Labor and Capital That Cost the Firm $200 Bundle Labor, L Capital, K Labor Cost, wL = $10L Capital Cost, rK = $20K Total Cost, wL + rK a 20 0 $200 $0 $200 b 14 3 $140 $60 $200 c 10 5 $100 $100 $200 d 6 7 $60 $140 $200 e 0 10 $0 $200 $200 cost $200 are listed in Table 6.2. These combinations of labor and capital are plotted on an isocost line, which represents all the combinations of inputs that have the same (iso-) total cost. Figure 6.3 shows three isocost lines. The $200 isocost line represents all the combinations of labor and capital that the firm can buy for $200, including the combinations a through e in Table 6.2. Along an isocost line, cost is fixed at a particular level, C, so by setting cost at C in Equation 6.6, we can write the equation for the C isocost line as C = wL + rK. Using algebra, we can rewrite this equation to show how much capital the firm can buy if it spends a total of C and purchases L units of labor: K = C w - L. r r (6.7) F IG U RE 6. 3 A Family of Isocost Lines K, Units of capital per year An isocost line shows all the combinations of labor and capital that cost the firm the same amount. The greater the total cost, the farther from the origin the isocost lies. All the isocosts have the same slope, - w/r = - 12. The 15 = $200 $20 10 = $200 $20 slope shows the rate at which the firm can substitute capital for labor holding total cost constant: For each extra unit of capital it uses, the firm must use two fewer units of labor to hold its cost constant. e d 5= $100 $20 c b $100 isocost $200 isocost $300 isocost a $100 = 10 $10 $200 = 20 $10 $300 = 30 $10 L, Units of labor per year 170 CHAPTER 6 Costs By substituting C = $200, w = $10, and r = $20 in Equation 6.7, we find that the $200 isocost line is K = 10 - 12 L. We can use Equation 6.7 to derive three properties of isocost lines. First, the points at which the isocost lines hit the capital and labor axes depend on the firm’s cost, C, and on the input prices. The C isocost line intersects the capital axis where the firm is using only capital. Setting L = 0 in Equation 6.7, we find that the firm buys K = C/r units of capital. In Figure 6.3, the $200 isocost line intersects the capital axis at $200/$20 = 10 units of capital. Similarly, the intersection of the isocost line with the labor axis is at C/w, which is the amount of labor the firm hires if it uses only labor. In the figure, the intersection of the $200 isocost line with the labor axis occurs at L = 20, where K = 10 - 12 * 20 = 0. Second, isocost lines that are farther from the origin have higher costs than those closer to the origin. Because the isocost lines intersect the capital axis at C/r and the labor axis at C/w, an increase in the cost shifts these intersections with the axes proportionately outward. The $100 isocost line hits the capital axis at 5 and the labor axis at 10, whereas the $200 isocost line intersects at 10 and 20. Third, the slope of each isocost line is the same. From Equation 6.7, if the firm increases labor by ΔL, it must decrease capital by ΔK = - w ΔL. r Dividing both sides of this expression by ΔL, we find that the slope of an isocost line, ΔK/ΔL, is -w/r. Thus, the slope of the isocost line depends on the relative prices of the inputs. The slope of the isocost lines in the figure is -w/r = -$10/$20 = 12. If the firm uses two more units of labor, ΔL = 2, it must reduce capital by one unit, ΔK = - 12 ΔL = -1, to keep its total cost constant. Because all isocost lines are based on the same relative prices, they all have the same slope, so they are parallel. The isocost line plays a similar role in the firm’s decision making as the budget line does in consumer decision making. Both an isocost line and a budget line are straight lines whose slopes depend on relative prices. However, they have an important difference. The consumer has a single budget line determined by the consumer’s income. The firm faces many isocost lines, each of which corresponds to a different level of expenditure the firm might make. A firm may incur a relatively low cost by producing relatively little output with few inputs, or it may incur a relatively high cost by producing a relatively large quantity. Combining Cost and Production Information. By combining the information about costs contained in the isocost lines with information about efficient production summarized by an isoquant, a firm chooses the lowest-cost way to produce a given level of output. We illustrate how a Japanese beer manufacturer picks the combination of labor and capital that minimizes its cost of producing 100 units of output. Figure 6.4 shows the isoquant for 100 units of output (based on the estimates of Flath, 2011) and the isocost lines for which the rental rate of a unit of capital is $8 per hour and the wage rate is $24 per hour. The firm minimizes its cost by using the combination of inputs on the isoquant that is on the lowest isocost line that touches the isoquant. The lowest possible isocost line that will allow the beer manufacturer to produce 100 units of output is the $2,000 isocost line. This isocost line touches the isoquant at the 6.3 Long-Run Costs 171 The beer manufacturer minimizes its cost of producing 100 units of output by producing at x (L = 50 and K = 100). This cost-minimizing combination of inputs is determined by the tangency between the q = 100 isoquant and the lowest isocost line, $2,000, that touches that isoquant. At x, the isocost is tangent to the isoquant, so the slope of the isocost, - w/r = - 3, equals the slope of the isoquant, which is the negative of the marginal rate of technical substitution. That is, the rate at which the firm can trade capital for labor in the input markets equals the rate at which it can substitute capital for labor in the production process. K, Units of capital per hour F IG U RE 6. 4 Cost Minimization q = 100 isoquant $3,000 isocost y 303 $2,000 isocost $1,000 isocost x 100 z 28 0 24 50 116 L, Units of labor per hour bundle of inputs x, where the firm uses L = 50 workers and K = 100 units of capital. How do we know that x is the least costly way to produce 100 units of output? We need to demonstrate that other practical combinations of input produce less than 100 units or produce 100 units at greater cost. If the firm spent less than $2,000, it could not produce 100 units of output. For example, each combination of inputs on the $1,000 isocost line lies below the isoquant, so the firm cannot produce 100 units of output for $1,000. The firm can produce 100 units of output using other combinations of inputs beside x; however, using these other bundles of inputs is more expensive. For example, the firm can produce 100 units of output using the combinations y (L = 24, K = 303) or z (L = 116, K = 28), but both of these combinations cost the firm $3,000. At the minimum-cost bundle, x, the isoquant is tangent to the isocost line: The slopes of the isocost and isoquant are equal and the isocost line touches the isoquant at only one point. Suppose that an isocost line hits the isoquant but is not tangent to it. Then the isocost line must cross the isoquant twice, as the $3,000 isocost line does at points y and z. However, if the isocost line crosses the isoquant twice, then part of the isoquant must lie below the isocost line. Consequently, another lower isocost line also touches the isoquant. Only if the isocost line is tangent to the isoquant—so that it touches the isoquant only once—can we conclude that we are on the lowest possible isocost line. At the point of tangency, the slope of the isoquant equals the slope of the isocost. As we discussed in Chapter 5, the slope of the isoquant is the firm’s marginal rate of technical substitution, which tells us how many units of capital the firm can replace with an extra unit of labor while holding output constant given its production 172 CHAPTER 6 Costs function. The slope of the isocost is the negative of the ratio of the wage to the cost of capital, -w/r, the rate at which the firm can trade capital for labor in input markets. Thus, at the input bundle where the firm minimizes its cost of producing a given level of output, the isoquant is tangent to the isocost line. Therefore, the firm chooses its inputs so that the marginal rate of technical substitution equals the negative of the relative input prices: MRTS = - w. r (6.8) To minimize the cost of producing a given level of output, the firm picks the bundle of inputs where the rate at which it can substitute capital for labor in the production process, the MRTS, exactly equals the rate at which it can trade capital for labor in input markets, -w/r. The formula for the beer manufacturer’s marginal rate of technical substitution is -1.5K/L. At the minimum-cost input bundle x, K = 100 and L = 50, so its MRTS is -3, which equals the negative of the ratio of the input prices it faces, -w/r = -24/8 = -3. In contrast, at y, the isocost cuts the isoquant so the slopes are not equal. At y, the MRTS is -18.9375, which is greater than the ratio of the input price, 3. Because the slopes are not equal at y, the firm can produce the same output at lower cost. As the figure shows, the cost of producing at y is $3,000, whereas the cost of producing at x is only $2,000. We can interpret the condition in Equation 6.8 in another way. We showed in Chapter 5 that the marginal rate of technical substitution equals the negative of the ratio of the marginal product of labor to that of capital: MRTS = -MPL/MPK. Thus, the cost-minimizing condition in Equation 6.8 (multiplying both sides by -1) is4 MPL w = . r MPK (6.9) This expression may be rewritten as MPL MPK . = r w (6.10) Equation 6.10 states the last-dollar rule: Cost is minimized if inputs are chosen so that the last dollar spent on labor adds as much extra output as the last dollar spent on capital. The beer firm’s marginal product of labor is MPL = 0.6q/L, and its marginal product of capital is MPK = 0.4q/K.5 At Bundle x, the beer firm’s marginal product of labor is 1.2 (= 0.6 * 100/50) and its marginal product of capital is 0.4. The last dollar spent on labor gets the firm MPL 1.2 = = 0.05 w 24 4See Appendix 6 at the end of this chapter for a calculus derivation of this cost-minimizing condition. 5Because the beer manufacturer’s production function is q = 1.52L0.6K 0.4, the marginal product of labor is MPL = 0q/0L = (0.6)1.52L(0.6 - 1)K0.4 = 0.6q/L, and the marginal product of capital is MPK = 0q/0K = (0.4)1.52L0.6K(0.4 - 1) = 0.4q/K. 6.3 Long-Run Costs 173 more units of output. The last dollar spent on capital also gets the firm MPK 0.4 = 0.05 = r 8 more units of output. Thus, spending one more dollar on labor at x gets the firm as much extra output as spending the same amount on capital. Equation 6.10 holds, so the firm is minimizing its cost of producing 100 units of output. If instead the firm uses more capital and less labor, producing at y, its MPL is 2.5 (= 0.6Q/L = 0.6 * 100/24) and the MPK is approximately 0.13 (≈ 0.4Q/K = 0.4 * 100/303). As a result, the last dollar spent on labor yields MPL/w ≈ 0.1 more output, whereas the last dollar spent on capital yields only a fourth as much extra output, MPK/r ≈ 0.017. At y, if the firm shifts one dollar from capital to labor, the reduction in capital causes output to fall by 0.017 units. Offsetting that reduction, the increase in labor causes output to increase by 0.1 units. Thus, the net gain is 0.083 units of output at the same cost. The firm should shift even more resources from capital to labor—which increases the marginal product of capital and decreases the marginal product of labor—until the firm is operating with the capital-labor bundle x, where Equation 6.10 holds and the last dollar spent on labor increases output just as much as the last dollar spent on capital. To summarize, a manager can use three equivalent rules to pick the lowest-cost combination of inputs to produce a given level of output when isoquants are smooth: the lowest-isocost rule, the tangency rule (Equation 6.9), and the last-dollar rule (Equation 6.10). Ma nagerial I mplication Cost Minimization by Trial and Error How should a manager minimize cost if the manager does not know the firm’s production function? The manager should use the last-dollar rule to determine the cost-minimizing combination of inputs through trial and error. The manager should experiment by adjusting each input slightly, holding other inputs constant, to learn how production and cost change and then use that information to choose a cost-minimizing bundle of inputs. (That is, managers don’t draw isoquants and isocost lines to make decisions, but they use the insights from such an analysis to obtain the last-dollar rule.) Factor Price Changes. Once the beer manufacturer determines the lowest-cost combination of inputs to produce a given level of output, it uses that method as long as the input prices remain constant. How should the firm change its behavior if the cost of one of the factors changes? Suppose that the wage falls from $24 to $8 but the rental rate of capital stays constant at $8. The firm minimizes its new cost by substituting away from the now relatively more expensive input, capital, toward the now relatively less expensive input, labor. The change in the wage does not affect technological efficiency, so it does not affect the isoquant in Figure 6.5. However, because of the wage decrease, the new isocost lines have a flatter slope, -w/r = -8/8 = -1, than the original isocost lines, -w/r = -24/8 = -3. The relatively steep original isocost line is tangent to the 100-unit isoquant at Bundle x (L = 50, K = 100). The new, flatter isocost line is tangent to the isoquant at Bundle v (L = 77, K = 52). Thus, the firm uses more labor and less capital as 174 CHAPTER 6 Costs Originally, the wage was $24 and the rental rate of capital was $8, so the lowest isocost line ($2,000) was tangent to the q = 100 isoquant at x(L = 50, K = 100). When the wage fell to $8, the isocost lines became flatter: Labor became relatively less expensive than capital. The slope of the isocost lines falls from -w/r = - 24/8 = - 3 to -8/8 = -1. The new lowest isocost line ($1,032) is tangent at v (L = 77, K = 52). Thus, when the wage falls, the firm uses more labor and less capital to produce a given level of output, and the cost of production falls from $2,000 to $1,032. K, Units of capital per hour F IG U RE 6. 5 Effect of a Change in Factor Price q = 100 isoquant Original isocost, $2,000 New isocost, $1,032 100 x v 52 0 50 77 L, Workers per hour labor becomes relatively less expensive. Moreover, the firm’s cost of producing 100 units falls from $2,000 to $1,032 because of the fall in the wage. This example illustrates that a change in the relative prices of inputs affects the mix of inputs that a firm uses. M ini-Case The Internet and Outsourcing To start a children’s pajama business, Philip Chigos and Mary Domenico designed their products, chose fabrics, and searched for low-cost workers in China or Mexico from an office in the basement below their San Francisco apartment. Increasingly, such mom-and-pop operations are sending their clothing, jewelry, and programming work to Sri Lanka, China, India, Mexico, and Eastern Europe. A firm outsources if it retains others to provide services that the firm had previously performed itself. Firms have always used outsourcing. For example, a restaurant buys goods such as butter and flour or finished products such as bread and pies from other firms or contracts with another firm to provide cleaning services. A profit-maximizing firm outsources if others can produce a good or service for less than the firm’s own cost. Though all domestic firms face the same factor prices, some firms can produce at lower cost than others because they specialize in a good or service. Many news outlets and politicians have been wringing their hands about outsourcing to other countries. The different factor prices that foreign firms face may allow them to produce at lower cost. In the past, most small firms could not practically outsource to other countries because of the high transaction costs of finding partners abroad and 6.3 Long-Run Costs 175 communicating with them. Now they can use the Internet and other communication technologies—such as e-mail, fax, and phone—to inexpensively communicate with foreign factories, transmit images and design specifications, and track inventory. Mr. Chigos used the Internet to find potential Chinese and Mexican manufacturers for the pajamas that Ms. Domenico designed. Hiring foreign workers is crucial to their nascent enterprise. Mr. Chigos claims, “We’d love it to say ‘Made in the U.S.A.’ and use American textiles and production.” However, if they did so, their cost would rise four to ten times, and “We didn’t want to sell our pajamas for $120.” One result of easy access to cheap manufacturing, he said, is that more American entrepreneurs may be able to turn an idea into a product. The would-be pajama tycoons plan to outsource to U.S. firms as well. They will use a Richmond, California, freight management company to receive the shipments, check the merchandise’s quality, and ship it to customers. They will market their clothes on the Internet and through boutique retailers. Indeed, their business will be entirely virtual: They have no manufacturing plant, storefront, or warehouse. As Mr. Chigos notes, “With the technology available today, we’ll never touch the product.” Thus, lower communication costs have made foreign outsourcing feasible by lowering transaction costs. Ultimately, however, such outsourcing occurs because the costs of outsourced activities are lower abroad. If relative factor prices (and hence slopes of isocost lines) are different abroad than at home, the manager of a firm with smooth isoquants should use a different factor mix when producing abroad, as Figure 6.5 illustrates. However, Q&A 6.2 shows that if all foreign prices for capital and labor are proportionally lower than domestic prices so that relative factor prices are the same, the firm should use the same technology as at home. Q& A 6.2 If it manufactures at home, a firm faces input prices for labor and capital of w and r and produces q units of output using L units of labor and K units of capital. Abroad, the wage and cost of capital are half as much as at home. If the firm manufactures abroad, will it change the amount of labor and capital it uses to produce q? What happens to its cost of producing quantity q? Answer 1. Determine whether the change in factor prices affects the slopes of the isoquant or the isocost lines. The change in input prices does not affect the isoquant, which depends only on technology (the production function). Moreover, cutting the input prices in half does not affect the slope of the isocost lines. The original slope was -w/r, and the new slope is -(w/2)/(r/2) = -w/r. 2. Using a rule for cost minimization, determine whether the firm changes its input mix. A firm minimizes its cost by producing where its isoquant is tangent to the lowest possible isocost line. That is, the firm produces where the slope of its isoquant, MRTS, equals the slope of its isocost line, -w/r. Because the slopes 176 CHAPTER 6 Costs of the isoquant and the isocost lines are unchanged after input prices are cut in half, the firm continues to produce using the same amount of labor, L, and capital, K, as originally. 3. Calculate the original cost and the new cost and compare them. The firm’s original cost of producing q units of output was wL + rK = C. Its new cost of producing the same amount of output is (w/2)L + (r/2)K = C/2. Thus, its cost of producing q falls by half when the input prices are halved. The isocost lines have the same slope as before, but the cost associated with each isocost line is halved. The Shapes of Long-Run Cost Curves The shapes of the long-run average cost and marginal cost curves depend on the shape of the long-run total cost curve. The long-run cost curve in panel a of Figure 6.6 corresponds to the long-run average and marginal cost curves in panel b. The longrun cost curve of this firm rises less than in proportion to increases in output at outputs below q* and then rises more rapidly. The corresponding long-run average cost curve first falls and then rises. The explanation for why the long-run average cost curve is U-shaped differs from those given for why short-run average cost curves are U-shaped. A key reason why the short-run average cost is initially downward sloping is that the average fixed cost curve is downward sloping: Spreading the fixed cost over more units of output lowers the average fixed cost per unit. In the long run fixed costs are less important than in the short run, and may be absent altogether, as we have assumed in this section. Therefore, we cannot rely on fixed costs to explain the initial downward slope of the long-run average cost curve. A major reason why the short-run average cost curve slopes upward at higher levels of output is diminishing marginal returns. In the long run, however, all factors can be increased, so diminishing marginal returns do not explain the upward slope of a long-run average cost curve. As with the short-run curves, the shape of the long-run curves is determined by the production function relationship between output and inputs. In the long run, returns to scale play a major role in determining the shape of the average cost curve and other cost curves. As we discussed in Chapter 5, increasing all inputs in proportion may cause output to increase more than in proportion (increasing returns to scale) at low levels of output, in proportion (constant returns to scale) at intermediate levels of output, and less than in proportion (decreasing returns to scale) at high levels of output. If a production function has this returns-to-scale pattern and the prices of inputs are constant, the long-run average cost curve must be U-shaped. To illustrate the relationship between returns to scale and long-run average cost, we use the returns-to-scale data given in Table 6.3. The firm produces one unit of output using a unit each of labor and capital. Given a wage and rental cost of capital of $12 per unit, the total cost and average cost of producing this unit are both $24. Doubling both inputs causes output to increase more than in proportion to 3 units, reflecting increasing returns to scale. Because cost only doubles while output triples, the average cost falls. A cost function is said to exhibit economies of scale if the average cost of production falls as output expands. 6.3 Long-Run Costs 177 F IG U RE 6. 6 Long-Run Cost Curves (a) Cost Curve Cost, $ (a) The long-run cost curve rises less rapidly than output at output levels below q* and more rapidly at higher output levels. (b) As a consequence, the marginal cost and average cost curves are U-shaped. The marginal cost crosses the average cost at its minimum at q*. C q* q, Quantity per day Cost per unit, $ (b) Marginal and Average Cost Curves MC AC q* q, Quantity per day T A BLE 6 .3 Returns to Scale and Long-Run Costs Returns to Scale Output, Q Labor, L Capital, K Cost, C = wL + rK Average Cost, AC = C/q 1 1 1 24 24 3 2 2 48 16 Increasing 6 4 4 96 16 Constant 8 8 8 192 24 Decreasing w = r = $12 per unit. 178 CHAPTER 6 Costs T ABLE 6 .4 Shape of Average Cost Curves in Canadian Manufacturing Scale Economies Economies of scale: Initially downward-sloping AC Share of Manufacturing Industries, % 57 Everywhere downward-sloping AC 18 L-shaped AC (downward-sloping, then flat) 31 8 U-shaped AC No economies of scale: Flat AC 23 Diseconomies of scale: Upward-sloping AC 14 Source: Robidoux and Lester (1992). Doubling the inputs again causes output to double as well—constant returns to scale—so the average cost remains constant. If an increase in output has no effect on average cost—the average cost curve is flat—there are no economies of scale. We sometimes refer to such a cost function as exhibiting constant costs, because average cost is constant. Doubling the inputs once more causes only a small increase in output—decreasing returns to scale—so average cost increases. A firm suffers from diseconomies of scale if average cost rises when output increases. Average long-run cost curves can have many different shapes. Perfectly competitive firms typically have U-shaped average cost curves. Average cost curves in noncompetitive markets may be U-shaped, L-shaped (average cost at first falls rapidly and then levels off as output increases), everywhere downward sloping, everywhere upward sloping, or have other shapes. Given fixed input prices, the shape of the average cost curve indicates whether the production process has economies or diseconomies of scale. Table 6.4 summarizes the shapes of average long-run cost curves of firms in various Canadian manufacturing industries (as estimated by Robidoux and Lester, 1992). The table shows that U-shaped average cost curves are the exception rather than the rule in Canadian manufacturing and that nearly one-third of these average cost curves are L-shaped. Some of these apparently L-shaped average cost curves may be part of a U-shaped curve with long, flat bottoms, where we don’t observe any firm producing enough to exhibit diseconomies of scale. M ini-Case Economies of Scale in Nuclear Power Plants Economies of scale can be achieved across an entire company through more efficient management. Over the last decade and a half, the industry consolidated substantially as many U.S. nuclear power plants switched from operating in a regulated to an unregulated market. In the 1970s and 1980s, the typical independent nuclear firm operated a single nuclear power plant. By the late 1990s, the average was three plants. However, the average jumped to six plants in 2000 and is now about nine plants. Indeed, the three largest companies—Entergy, Exelon, and NextEra—operate about one-third of all the nuclear capacity in the United States. This consolidation improves operating efficiency in several ways. Rather than have a single plant use contract employees to perform infrequent tasks, such as 6.3 Long-Run Costs 179 refueling outages, which take place on average every 18 months, a consolidated nuclear company can hire highly skilled employees and train them to appreciate the idiosyncrasies of the company’s reactors. In addition, consolidated firms may have employees and managers share best practices across plants. Gary Leidich, the president of FirstEnergy Nuclear, said that when the company acquired three nuclear plants they went from three separate facilities, “each pretty much doing their own thing” to a corporate organization where managers work together. For example, all the plant operators have a daily 7:30 a.m. conference call to discuss potential problems, and managers at FirstEnergy travel from plant to plant. These economies of scale due to consolidation result in more efficient plants with substantially fewer outages. Consolidation decreases plant outages from, on average, 21 days per year to 15 days per year. Although this change may not seem substantial, a typical 2,000 megawatt nuclear power plant produces about $100,000 worth of power every hour, so 6 days of extra production increases revenues by over $14 million a year. According to the estimates of Davis and Wolfram (2012), consolidation increases efficiency (net energy generation relative to plant capacity) and thereby reduces cost per unit of energy produced. The number of extra plants owned by each firm ranges from 0 to 16. According to their estimates, a firm with 16 extra plants would increase efficiency by 7.7 percentage points. Q& A 6.3 What is the shape of the long-run cost function for a fixed-proportions production function (Chapter 5) in which it takes one unit of labor and one unit of capital to produce one unit of output? What is the shape of the average cost curve? Does it have economies or diseconomies of scale? Answer 1. Because no substitution is possible with a fixed-proportion production function, multiply the inputs ( = the number of units of output) by their prices, and sum to determine total cost. The long-run cost of producing q units of output is C(q) = wL + rK = wq + rq = (w + r)q. Cost rises in proportion to output. The long-run cost curve is a straight line with a slope of w + r. 2. Divide the total cost function by q to get the average cost function. The average cost function is AC(q) = C(q)/q = [(w + r)q]/q = w + r. Because the average cost for any quantity is w + r, the average cost curve is a horizontal straight line at w + r. Moreover, because the average cost does not change when the quantity of output changes, the cost function does not have either economies or diseconomies of scale. 180 CHAPTER 6 Costs Long-Run Average Cost as the Envelope of Short-Run Average Cost Curves Capital is flexible in the long run but not in the short run. Therefore, the firm has more flexibility in how it produces in the long run than in the short run. Any combination of inputs the firm uses in the short run, the firm could use in the long run. However, the firm may be able to use a different combination of inputs to produce at lower cost in the long run, when it is able to vary its capital input. For this reason, the long-run average cost is always equal to or below the short-run average cost. Suppose, initially, that the firm in Figure 6.7 has only three possible plant sizes. The firm’s short-run average cost curve is SRAC 1 for the smallest possible plant. The average cost of producing q1 units of output using this plant, point a on SRAC 1, is $10. If instead the plant used the next larger plant size, its cost of producing q1 units of output, point b on SRAC 2, would be $12. Thus, if the firm knows that it will produce only q1 units of output, it minimizes its average cost by using the smaller plant size. If it expects to be producing q2, its average cost is lower on the SRAC 2 curve, point e, than on the SRAC 1 curve, point d. In the long run, the firm chooses the plant size that minimizes its cost of production, so it picks the plant size that has the lowest average cost for each possible output level. It opts for the small plant size at q1, whereas it uses the medium plant size at q2. Thus, the long-run average cost curve is the solid, scalloped section of the three short-run cost curves. If many possible plant sizes are possible, the long-run average curve, LRAC, is smooth and U-shaped. The LRAC includes one point from each possible short-run average cost curve. This point, however, is not necessarily the minimum point of a short-run curve. For example, the LRAC includes a on SRAC 1 and not its minimum point, c. A small plant operating at minimum average cost cannot produce at as low an average cost as a slightly larger plant that is taking advantage of economies of scale. F IG U RE 6. 7 Long-Run Average Cost as the Envelope of Short-Run Average Cost Curves Average cost, $ If there are only three possible plant sizes, with short-run average costs SRAC1, SRAC2, and SRAC3, the long-run average cost curve is the solid, scalloped portion of the SRAC 3 SRAC 1 SRAC 3 b 12 10 three short-run curves. LRAC is the smooth and U-shaped long-run average cost curve if there are many possible short-run average cost curves. a LRAC SRAC 2 d c e 0 q1 q2 q, Output per day 6.3 Long-Run Costs M ini-Case Costs per unit, $ Long-Run Cost Curves in Beer Manufacturing and Oil Pipelines 40 30 20 10 0 200 181 Here we illustrate the relationship between long-run and short-run cost curves for our beer manufacturing firm and for oil pipelines. Beer Manufacturing The first graph shows the relationship between short-run and long-run average cost curves for the beer manufacturer. Because this production function has constant returns to scale, doubling both inputs doubles output, so the long-run average cost, LRAC, is constant. If capital is fixed at 200 units, the firm’s short-run average cost curve is SRAC 1. If the firm proSRAC 1 duces 200 units of output, its short-run and long-run average 2 1 costs are equal. At any other outSRMC SRMC put, its short-run cost is higher SRAC 2 than its long-run cost. The short-run marginal cost curves, SRMC 1 and SRMC 2, are upward sloping and equal the LRAC = LRMC corresponding U-shaped shortrun average cost curves, SRAC 1 and SRAC 2, only at their minimum points, $20. In contrast, because the long-run average cost is horizontal at $20, the longrun marginal cost curve, LRMC, is horizontal at $20. Thus, the 600 1,200 long-run marginal cost curve is q, Cases of beer per hour not the envelope of the short-run marginal cost curves. Oil Pipelines Oil companies use the information in the second graph6 (next page) to choose what size pipe to use to deliver oil. In the figure, the 8″ SRAC curve is the shortrun average cost curve for a pipe with an 8-inch diameter. The long-run average cost curve, LRAC, is the envelope of all possible short-run average cost curves. It is more expensive to lay larger pipes than smaller ones, so a firm does not want to install unnecessarily large pipes. However, the average cost of sending a substantial quantity of oil through a single large pipe is lower than that of sending it through two smaller pipes. For example, the average cost per barrel of sending 200,000 barrels per day through two 16-inch pipes is 1.67 ( = $50/$30) greater than through a single 26-inch pipe. Because the company incurs large fixed costs in laying miles and miles of pipelines, and because pipes last for years, it does not vary the size of pipes in the short run. However, in the long run, the oil company installs the ideal pipe size to handle its flow of oil. Indeed, because several oil companies often share 6Exxon Company, U.S.A., Competition in the Petroleum Industry, 1975, p. 30. Reprinted with permission. 182 CHAPTER 6 Costs Cost per barrel mile interstate pipelines to take advantage of the large economies of scale, very large diameter pipes are typically installed. 150 100 8" SRAC 10" SRAC 12" SRAC 16" SRAC 20" SRAC 50 10 0 6.4 26" SRAC 40" SRAC LRAC 10 20 40 100 200 400 1000 2000 Thousand barrels per day (log scale) The Learning Curve Average cost may fall over time for three reasons. First, operating at a larger scale in the long run may lower average cost due to increasing returns to scale (IRS). Second, technological progress (Chapter 5) may increase productivity and thereby lower average cost. Third, a firm may benefit from learning by doing: the productive skills and knowledge that workers and managers gain from experience. Workers who are given a new task may perform it slowly the first few times they try, but their speed increases with practice. Managers may learn how to organize production more efficiently, discover which workers to assign to which tasks, and determine where more inventories are needed and where they can be reduced. Engineers may optimize product designs by experimenting with various production methods. For these and other reasons, the average cost of production tends to fall over time, and the effect is particularly strong with new products. In some firms, learning by doing is a function of the time elapsed since a particular product or production process was introduced. However, more commonly, learning is a function of cumulative output: the total number of units of output produced since the product was introduced. The learning curve is the relationship between average costs and cumulative output. The learning curve for Intel central processing units (CPUs) in panel a of Figure 6.8 shows that Intel’s average cost fell very rapidly with the first few million units of cumulative output, but then dropped relatively slowly with additional units (Salgado, 2008). If a firm is operating in the economies of scale section of its average cost curve, expanding output lowers its cost for two reasons. Its average cost falls today because 6.4 The Learning Curve 183 F IG U RE 6. 8 Learning by Doing (a) As Intel produced more cumulative CPUs, the average cost of production fell (Salgado, 2008). (b) In any one period, extra production reduces a firm’s average cost due to economies of scale: because q1 6 q2 6 q3, A is higher than B, which is higher than C. Extra production in one period reduces average cost in the future because of learning by doing. To produce q2 this period costs B on AC1, but to produce that same output in the next period would cost only b on AC2. If the firm produces q3 instead of q2 in this period, its average cost in the next period is AC3 instead of AC2 because of additional learning by doing. Thus, extra output in this period lowers the firm’s cost in two ways: It lowers average cost in this period due to economies of scale and lowers average cost for any given output level in the next period due to learning by doing. (b) Economies of Scale and Learning by Doing Average cost, $ Average cost per CPU, $ (a) Learning Curve for Intel Central Processing Units $100 80 60 Economies of scale A B 40 b 20 c Learning by doing 0 50 100 150 200 Cumulative production of Pentium CPU, Millions of units C q1 q2 AC 1 AC 2 AC 3 q3 q, Output per period of economies of scale, and for any given level of output, its average cost is lower in the next period due to learning by doing. In panel b of Figure 6.8, the firm is producing q1 units of output at point A on average cost curve AC 1 in the first period. We assume that each period is long enough that the firm can vary all factors of production. If the firm expands its output to q2 in Period 1, its average cost falls to B because of economies of scale. The learning by doing in Period 1 results in a lower average cost, AC 2 in Period 2. If the firm continues to produce q2 units of output in Period 2, its average cost falls to b on AC 2. If instead of expanding output to q2 in Period 1, the firm expands to q3, its average cost is even lower in Period 1 (C on AC 1) due to even greater economies of scale. Moreover, its average cost curve, AC 3, in Period 2 is even lower due to the extra experience gained from producing more output in Period 1. If the firm continues to produce q3 in Period 2, its average cost is c on AC 3. Thus all else being the same, if learning by doing depends on cumulative output, firms have an incentive to produce more in any one period than they otherwise would to lower their costs in the future. Mini-Case Learning by Drilling Learning by doing can substantially reduce the cost of drilling oil wells. Two types of firms work together to drill oil wells. Oil production companies such as ExxonMobil and Chevron perform the technical design and planning of wells to be drilled. The actual drilling is performed by drilling companies that own and staff drilling rigs. The time it takes to drill a well varies across fields, which vary in terms of the types of rock covering the oil and the depth of the oil. 184 CHAPTER 6 Costs Kellogg (2011) found that the more experience—the cumulative number of wells that the oil production firm drilled in the field over the past two years— the less time it takes the firm to drill another well. His estimated learning curve shows that drilling time decreases rapidly at first, falling by about 15% after the first 25 wells have been drilled, but that drilling time does not fall much more with additional experience. This decrease in drilling time is the sum of the benefits from two types of experience. The time it takes to drill a well falls as the production company drills (1) more wells in the field and (2) more wells in that field with a particular drilling company. The second effect occurs because the two firms learn to work better together in a particular field. Because neither firm can apply its learning with a particular partner to its work with another partner, production companies prefer to continue to work with the same drilling rig firms over time. The reduction in drilling time from a production firm’s average stand-alone experience over the past two years is 6.4% or 1.5 fewer days to drill a well. This time savings reduces the cost of drilling a well by about $16,300. The relationship-specific learning from experience due to working with a drilling company for the average duration over two years reduces drilling time per well by 3.8%, or about $9,700 per well. On average, the reduction in drilling time from working with one rig crew regularly is twice as much as from working with rigs that frequently switch from one production firm to another. 6.5 The Costs of Producing Multiple Goods If a firm produces two or more goods, the cost of one good may depend on the output level of another. Outputs are linked if a single input is used to produce both of them. For example, cattle provide beef and hides, and oil supplies both heating fuel and gasoline. It is less expensive to produce beef and hides together than separately. If the goods are produced together, a single animal yields one unit of beef and one hide. If beef and hides are produced separately (throwing away the unused good), the same amount of output requires two animals and more labor. A cost function exhibits economies of scope if it is less expensive to produce goods jointly than separately (Panzar and Willig, 1977, 1981). All else the same, if a firm has such a cost function, it can lower its total cost by producing its products together (say at one plant) rather than separately (at two plants). A measure of the degree of economies of scope (SC) is SC = C(q1, 0) + C(0, q2) - C(q1, q2) C(q1, q2) , where C(q1, 0) is the cost of producing q1 units of the first good by itself, C(0, q2) is the cost of producing q2 units of the second good, and C(q1, q2) is the cost of producing both goods together. If the cost of producing the two goods separately, C(q1,0) + C(0, q2), is the same as producing them together, C(q1, q2), then SC is zero. If it is cheaper to produce the goods jointly, SC is positive. If SC is negative, there are diseconomies of scope, and the two goods should be produced separately. 6.5 The Costs of Producing Multiple Goods M ini-Case Scope M a nagerial So lution Technology Choice at Home Versus Abroad 185 Empirical studies show that some processes have economies of scope, others have none, and some have diseconomies of scope. In Japan, there are substantial economies of scope in producing and transmitting electricity, SC = 0.2 (Ida and Kuwahara, 2004), and in broadcasting for television and radio, SC = 0.12 (Asai, 2006). Growitsch and Wetzel (2009) found that there are economies of scope from combining passenger and freight services for the majority of 54 railway firms from 27 European countries. Yatchew (2000) concluded that there are scope economies in distributing electricity and other utilities in Ontario, Canada. Kong et al. (2009) found that Chinese airports exhibit substantial economies of scope. In Switzerland, some utility firms provide gas, electricity, and water, while others provide only one or two of these utilities. Farsi et al. (2008) estimated that most firms have scope economies. The SC ranges between 0.04 and 0.15 for a median-size firm, but scope economies could reach 20% to 30% of total costs for small firms, which may help explain why only some firms provide multiple utilities. Friedlaender, Winston, and Wang (1983) found that for American automobile manufacturers, it is 25% less expensive (SC = 0.25) to produce large cars together with small cars and trucks than to produce large cars separately and small cars and trucks together. However, there are no economies of scope from producing trucks together with small and large cars. Producing trucks separately from cars is efficient. Cummins et al. (2010) tested whether U.S. insurance firms do better by selling both life-health and property-liability insurance or by specializing, and found that the firms should specialize due to diseconomies of scope. Similarly, Cohen and Paul (2011) estimated that drug treatment centers have diseconomies of scope, so they should specialize in either outpatient or inpatient treatment. If a U.S. semiconductor manufacturing firm shifts production from the firm’s home plant to one abroad, should it use the same mix of inputs as at home? The firm may choose to use a different technology because the firm’s cost of labor relative to capital is lower abroad than in the United States. If the firm’s isoquant is smooth, the firm uses a different bundle of inputs abroad than at home given that the relative factor prices differ (as Figure 6.5 shows). However, semiconductor manufacturers have kinked isoquants. Figure 6.9 shows an isoquant for a semiconductor manufacturing firm that we examined in Chapter 5 in the Mini-Case “A Semiconductor Isoquant.” In its U.S. plant, the semiconductor manufacturing firm uses a wafer-handling stepper technology because the C 1 isocost line, which is the lowest isocost line that touches the isoquant, hits the isoquant at that technology. The firm’s cost of both inputs is less abroad than in the United States, and its cost of labor is relatively less than the cost of capital at its foreign plant than at its U.S. plant. The slope of its isocost line is -w/r, where w is the wage and r is the rental cost of the manufacturing equipment. The smaller w is relative to r, the less steeply sloped is its isocost curve. Thus, the firm’s foreign isocost line is flatter than its domestic C 1 isocost line. 186 CHAPTER 6 Costs If the firm’s isoquant were smooth, the firm would certainly use a different technology at its foreign plant than in its home plant. However, its isoquant has kinks, so a small change in the relative input prices does not necessarily lead to a change in production technology. The firm could face either the C 2 or C 3 isocost curves, both of which are flatter than the C 1 isocost. If the firm faces the C 2 isocost line, which is only slightly flatter than the C 1 isocost, the firm still uses the capital-intensive wafer-handling stepper technology in its foreign plant. However, if the firm faces the much flatter C 3 isocost line, which hits the isoquant at the stepper technology, it switches technologies. (If the isocost line were even flatter, it could hit the isoquant at the aligner technology.) Even if the wage change is small so that the firm’s isocost is C 2 and the firm does not switch technologies abroad, the firm’s cost will be lower abroad with the same technology because C 2 is less than C 1. However, if the wage is low enough that it can shift to a more labor-intensive technology, its costs will be even lower: C 3 is less than C 2. Thus, whether the firm uses a different technology in its foreign plant than in its domestic plant turns on the relative factor prices in the two locations and whether the firm’s isoquant is smooth. If the isoquant is smooth, even a slight difference in relative factor prices will induce the firm to shift along the isoquant and use a different technology with a different capital-labor ratio. However, if the isoquant has kinks, the firm will use a different technology only if the relative factor prices differ substantially. In the United States, the semiconductor manufacturer produces using a wafer-handling stepper on isocost C1. At its plant abroad, the wage is lower, so it faces a flatter isocost curve. If the wage is only slightly lower, so that its isocost is C2, it produces the same way as at home. However, if the wage is much lower so that the isocost is C3, it switches to a stepper technology. K, Units of capital per day F IG U RE 6. 9 Technology Choice 200 ten-layer chips per day isoquant Wafer-handling stepper Stepper Aligner C 1 isocost 0 1 C 2 isocost 3 C 3 isocost 8 L, Workers per day Questions 187 SUMMARY From all technically efficient production processes, a cost-minimizing firm chooses the one that is economically efficient. The economically efficient production process is the technically efficient process for which the cost of producing a given quantity of output is lowest. 3. Long-Run Costs. Over a long-run planning horizon, all inputs can be adjusted. In some cases there might be a minimum level of capital necessary for the firm to produce anything at all, implying that there might be fixed costs even in the long run. However, these costs can be avoided if the firm shuts down and are therefore not sunk over a longrun planning horizon. If there are no fixed costs, then average total cost and average variable cost are identical. The firm chooses to use the combination of inputs that minimizes its cost. To produce a given output level, it chooses the lowest isocost line that touches the relevant isoquant, which is tangent to the isoquant. Equivalently, to minimize cost, the firm adjusts inputs until the last dollar spent on any input increases output by as much as the last dollar spent on any other input. If the firm calculates the cost of producing every possible output level given current input prices, it knows its cost function: Cost is a function of the input prices and the output level. If the firm’s average cost falls as output expands, it has economies of scale. If its average cost rises as output expands, there are diseconomies of scale. 1. The Nature of Costs. In making decisions about production, managers need to take into account the opportunity cost of an input, which is the value of the input’s best alternative use. For example, if the manager is the owner of the company and does not receive a salary, the amount that the owner could have earned elsewhere—the foregone earnings—is the opportunity cost of the manager’s time and is relevant in deciding whether the firm should produce or not. A durable good’s opportunity cost depends on its current alternative use. If the past expenditure for a durable good is sunk— that is, it cannot be recovered—then that input has no opportunity cost and the sunk cost should not influence current production decisions. 2. Short-Run Costs. In the short run, the firm can adjust some factors, such as labor, while other factors, such as capital, are fixed. Consequently, total cost is the sum of variable costs and fixed costs. Average cost is total cost divided by the number of units of output produced. Similarly, average variable cost is variable cost divided by output. Marginal cost is the amount by which a firm’s cost changes if the firm produces one more unit of output. At quantities where the marginal cost curve is below the average cost curve, the average cost curve is downward sloping. Where the marginal cost curve is above the average cost curve, the average cost curve is upward sloping. Thus, the marginal cost curve cuts the average cost curve at its minimum point. Given that input prices are constant, the shapes of the variable cost and the cost-per-unit curves are determined by the production function. If labor is the only variable factor in the short run, the shape of short-run cost curves reflects the marginal product of labor. 4. The Learning Curve. A firm that introduces a new product or service often benefits from increased productivity as it gains experience and learns how to produce at lower cost, a process called learning by doing. Workers who are given a new task will typically speed up and make fewer mistakes with practice. The learning curve describes the relationship between average cost and cumulative output over time. This curve typically slopes downward, reflecting the decline in cost that arises from learning by doing. 5. The Costs of Producing Multiple Goods. If it is less expensive for a firm to produce two goods jointly rather than separately, there are economies of scope. If there are diseconomies of scope, it is less expensive to produce the goods separately. The presence or absence of economies of scope is important in determining the portfolio of products that the firm produces. Q U E S T ION S All exercises are available on MyEconLab; * = answer at the back of this book; C = use of calculus may be necessary. The Nature of Costs 1.1. Executives at Leonesse Cellars, a premium winery in Southern California, were surprised to learn that shipping wine by sea to some cities in Asia was less expensive than sending it to the East Coast of the United States, so they started shipping to Asia (David Armstrong, “Discount Cargo Rates Ripe for the Taking,” San Francisco Chronicle, August 28, 188 CHAPTER 6 Costs 2005). Because of the large U.S. trade imbalance with major Asian nations, cargo ships arrive at West Coast seaports fully loaded but return to Asia half to completely empty. Use the concept of opportunity cost to help explain the differential shipping rates. 1.2. Carmen bought a $125 ticket to attend the Outside Lands Music & Arts Festival in San Francisco. Because it stars several of her favorite rock groups, she would have been willing to pay up to $200 to attend the festival. However, her friend Bessie invites Carmen to go with her to the Monterey Bay Aquarium on the same day. That trip would cost $50, but she would be willing to pay up to $100. What is her opportunity cost of going to the festival? (Hint: See Q&A 6.1.) 1.3. Many corporations allow CEOs to use the firm’s corporate jet for personal travel (see the Mini-Case “Company Jets” in Chapter 7 for more details). The Internal Revenue Service (IRS) requires that the firm report personal use of its corporate jet as taxable executive income, and the Securities and Exchange Commission (SEC) requires that publicly traded corporations report the value of this benefit to shareholders. An important issue is the determination of the value of this benefit. The IRS values a CEO’s personal flight at or below the price of a first-class ticket. The SEC values the flight at the “incremental” cost of the flight: the additional costs to the corporation of the flight. The third alternative is the market value of chartering an aircraft. Of the three methods, the first-class ticket is least expensive and the chartered flight is most expensive. a. What factors (such as fuel) determine the marginal explicit cost to a corporation of an executive’s personal flight? Does any one of the three valuation methods correctly determine the marginal explicit cost? Francisco Chronicle, February 8, 1993, C1.) Discuss whether Agassi’s statement is reasonable. 2.2. In the twentieth century, department stores and supermarkets largely replaced smaller specialty stores, as consumers found it more efficient to go to one store rather than many stores. Consumers incur a transaction or search cost to shop, primarily the opportunity cost of their time. This transaction cost consists of a fixed cost of traveling to and from the store and a variable cost that rises with the number of different types of items the consumer tries to find on the shelves. By going to a supermarket that carries meat, fruits and vegetables, and other items, consumers can avoid some of the fixed transaction costs of traveling to a separate butcher shop, produce mart, and so forth. Use math to explain why a shopper’s average costs are lower when buying at a single supermarket than from many stores. (Hint: Define the goods as the items purchased and brought home.) 2.3. Give the formulas for and plot AFC, MC, AVC, and AC if the cost function is a. C = 10 + 10q, b. C = 10 + q2, or c. C = 10 + 10q - 4q2 + q3. C 2.4. In 1796, Gottfried Christoph Härtel, a German music publisher, calculated the cost of printing music using an engraved plate technology and used these estimated cost functions to make production decisions. Härtel figured that the fixed cost of printing a musical page—the cost of engraving the plates— was 900 pfennigs. The marginal cost of each additional copy of the page is 5 pfennigs (Scherer, 2001). a. Graph the total cost, average total cost, average variable cost, and marginal cost functions. b. What is the marginal opportunity cost to the corporation of an executive’s personal flight? b. Is there a cost advantage to having only one music publisher print a given composition? Why? *1.4. A firm purchased copper pipes a few years ago at $10 per pipe and stored them, using them only as the need arises. The firm could sell its remaining pipes in the market at the current price of $9. What is the opportunity cost of each pipe and what is the sunk cost? c. Härtel used his data to do the following type of analysis. Suppose he expects to sell exactly 300 copies of a composition at 15 pfennigs per page of the composition. What is the greatest amount the publisher is willing to pay the composer per page of the composition? Short-Run Costs *2.1. “ ‘There are certain fixed costs when you own a plane,’ [Andre] Agassi explained during a break in the action at the Volvo/San Francisco tennis tournament, ‘so the more you fly it, the more economic sense it makes. . . . The first flight after I bought it, I took some friends to Palm Springs for lunch.” ’ (Scott Ostler, “Andre Even Flies Like a Champ,” San 2.5. Gail works in a flower shop, where she produces 10 floral arrangements per hour. She is paid $10 an hour for the first eight hours she works and $15 an hour for each additional hour she works. What is the firm’s cost function? What are its AC, AVC, and MC functions? Draw the AC, AVC, and MC curves. *2.6. A firm builds shipping crates out of wood. How does the cost of producing a 1-cubic-foot crate (each Questions side is 1-foot square) compare to the cost of building an 8-cubic-foot crate if wood costs $1 a square foot and the firm has no labor or other costs? More generally, how does cost vary with volume? 2.7. The only variable input a janitorial service firm uses to clean offices is workers who are paid a wage, w, of $10 an hour. Each worker can clean four offices in an hour. Use math to determine the variable cost, the average variable cost, and the marginal cost of cleaning one more office. Draw a diagram like Figure 6.1 to show the variable cost, average variable cost, and marginal cost curves. 2.8. A firm has a Cobb-Douglas production function, q = ALαKβ, where α + β 6 1. On the basis of this information, what properties does its cost function have? For example, a U.S. chemical firm has a production function of q = 10L0.32K0.56 (based on Hsieh, 1995). If it faces factor prices of w = 10 and r = 20 and its capital is fixed at K = 100, what are its shortrun cost, variable cost, average variable cost, and marginal variable cost functions? Plot these curves. 2.9. Equation 6.5 gives the short run variable cost function for Japanese beer as VC = 0.55q1.67. If the fixed cost is 600 and the firm produces 550 units, determine the C, VC, MC, AFC, and AVC. What happens to these costs if the firm increases its output to 600? Long-Run Costs 3.1. The invention of a new machine serves as a mobile station for receiving and accumulating packed flats of strawberries close to where they are picked, reducing workers’ time and burden of carrying full flats of strawberries. According to Rosenberg (2004), a machine-assisted crew of 15 pickers produces as much output, q*, as that of an unaided crew of 25 workers. In a 6-day, 50-hour workweek, the machine replaces 500 worker-hours. At an hourly wage cost of $10, a machine saves $5,000 per week in labor costs, or $130,000 over a 26-week harvesting season. The cost of machine operation and maintenance expressed as a daily rental is $200, or $1,200 for a six-day week. Thus, the net savings equal $3,800 per week, or $98,800 for 26 weeks. a. Draw the q* isoquant assuming that only two production methods are available (pure labor and labor-machine). Label the isoquant and axes as thoroughly as possible. b. Add an isocost line to show which technology the firm chooses (be sure to measure wage and rental costs on a comparable time basis). c. Draw the corresponding cost curves (with and without the machine), assuming constant returns to scale, and label the curves and the axes as thoroughly as possible. 189 *3.2. A bottling company uses two inputs to produce bottles of the soft drink Sludge: bottling machines (K) and workers (L). The isoquants have the usual smooth shape. The machine costs $1,000 per day to run and the workers earn $200 per day. At the current level of production, the marginal product of the machine is an additional 200 bottles per day, and the marginal product of labor is 50 more bottles per day. Is this firm producing at minimum cost? If it is minimizing cost, explain why. If it is not minimizing cost, explain how the firm should change the ratio of inputs it uses to lower its cost. (Hint: Examine the conditions for minimizing cost in Equations 6.8, 6.9, and 6.10.) 3.3. Suppose that the government subsidizes the cost of workers by paying for 25% of the wage (the rate offered by the U.S. government in the late 1970s under the New Jobs Tax Credit program). What effect will this subsidy have on the firm’s choice of labor and capital to produce a given level of output? What happens if both capital and labor are subsidized at 25%? (Hint: See Q&A 6.2.) *3.4. The all-American baseball is made using cork from Portugal, rubber from Malaysia, yarn from Australia, and leather from France, and it is stitched (108 stitches exactly) by workers in Costa Rica. To assemble a baseball takes one unit each of these inputs. Ultimately, the finished product must be shipped to its final destination—say, Cooperstown, New York. The materials used cost the same anywhere. Labor costs are lower in Costa Rica than in a possible alternative manufacturing site in Georgia, but shipping costs from Costa Rica are higher. What production function is used? What is the cost function? What can you conclude about shipping costs if it is less expensive to produce baseballs in Costa Rica than in Georgia? 3.5. California’s State Board of Equalization imposed a higher tax on “alcopops,” flavored beers containing more than 0.5% alcohol-based flavorings, such as vanilla extract (Guy L. Smith, “On Regulation of ‘Alcopops,’ ”San Francisco Chronicle, April 10, 2009). Such beers are taxed as distilled spirits at $3.30 a gallon rather than as beer at 20¢ a gallon. In response, manufacturers reformulated their beverages so as to avoid the tax. By early 2009, instead of collecting a predicted $38 million a year in new taxes, the state collected only about $9,000. Use an isocost-isoquant diagram to explain the firms’ response. (Hint: Alcohol-based flavors and other flavors may be close to perfect substitutes.) 3.6. A U.S. electronics firm is considering moving its production to a plant in Mexico. Its estimated production function is q = L0.5K0.5 (based on Hsieh, 1995). 190 CHAPTER 6 Costs The U.S. factor prices are w = r = 10. In Mexico, the wage is half that in the United States, but the firm faces the same cost of capital: w* = 5 and r* = r = 10. What are L and K, and what is the cost of producing q = 100 units in both countries? *3.7. What is the long-run cost function for a fixedproportions production function for which it takes two units of labor and one unit of capital to produce one unit of output as a function of the wage, w, and the price of capital, r? What is the cost function if the production function is q = L + K? (Hint: See Q&A 6.3.) 3.8. A U-shaped long-run average cost curve is the envelope of U-shaped short-run average cost curves. On what part of the curve (downward sloping, flat, or upward sloping) does a short-run curve touch the long-run curve? The Learning Curve 4.1. In what types of industry would you expect to see substantial learning by doing? Why? *4.2. A firm’s learning curve, which shows the relationship between average cost and cumulative output (the sum of its output since the firm started producing), is AC = a + bN -r; where AC is its average cost; N is its cumulative output; a, b, and r are constants; and 0 6 r 6 1. a. What is the firm’s AC if r = 0? What can you say about the firm’s ability to learn by doing? b. If r exceeds zero, what can you say about the firm’s ability to learn by doing? What happens to its AC as its cumulative output, N, gets extremely large? Given this result, what is your interpretation of a? 4.3. In the Mini-Case “Learning by Drilling,” an oil drilling firm’s average cost when working with production company M depends partly on its own cumulative drilling experience, N, and partly on the cumulative amount of drilling it has done jointly with production company M. Would an average cost curve AC = a + b1N -r + b2M -s exhibit such learning by doing? Explain. (Note: a, b1, b2, r, and s are all positive constants.) The Costs of Producing Multiple Goods 5.1. The United Kingdom started regulating the size of grocery stores in the early 1990s, and today the average size of a typical U.K. grocery store is roughly half the size of a typical U.S. store and two-thirds the size of a typical French store (Haskel and Sadun, 2011). What implications would such a restriction on size have on a store’s average costs? Discuss in terms of economies of scale and scope. 5.2. Laura sells mushrooms and strawberries to tourists. If Laura spends the morning collecting only mushrooms, she picks 8 pints; if she spends the morning picking strawberries, she collects 6 pints. If she picks some of each, however, she can harvest more total pints: 6 pints of mushrooms and 4 pints of strawberries. Suppose that Laura’s time is valued at $10 an hour. What can you say about her economies of scope? That is, what is the sign of her measure of economies of scope, SC? *5.3. A refiner produces heating fuel and gasoline from crude oil in virtually fixed proportions. What can you say about economies of scope for such a firm? What is the sign of its measure of economies of scope, SC? Managerial Problem 6.1. In Figure 6.9, show that there are wage rates and capital rental costs such that the firm is indifferent between using the wafer-handling stepper technology and the stepper technology. How does this wage/cost of capital ratio compare to those in the C 2 and C 3 isocosts? Spreadsheet Exercises 7.1. The production function for a firm is q = -0.6L3 + 18L2K + 10L where q is the amount of output, L is the number of labor hours per week, and K the amount of capital. The wage is $100 and the rental rate is $800 per time period. a. Using Excel, calculate the total short-run output, q(L), for L = 0, 1, 2, c 20, given that capital is fixed in the short run at K = 1. Also, calculate the average product of labor, APL, and the marginal product of labor, MPL. (You can estimate the MPL for L = 2 as q(2) - q(1), and so on for other levels of L.) b. For each quantity of labor in (a), calculate the variable cost, VC; the total cost, C; the average variable cost, AVC; the average cost, AC; and the marginal cost, MC. Using Excel, draw the AVC, AC, and MC curves in a diagram. c. For each quantity of labor in (a), calculate w/APL and w/MPL and show that they equal AVC and MC respectively. Explain why these relationships hold. 7.2. A furniture company has opened a small plant that builds tables. Jill, the production manager, knows the fixed cost of the plant, F = $78 per day, and includes the cost of the building, tools, and equipment. Variable costs include labor, energy costs, and wood. Jill Questions wants to know the cost function. She conducts an experiment in which she varies the daily production level over a 10-day period and observes the associated daily cost. The daily output levels assigned are 1, 2, 4, 5, 7, 8, 10, 12, 15, and 16. The associated total costs for these output levels are 125, 161, 181, 202, 207, 222, 230, 275, 390, and 535, respectively. a. Use the Trendline tool in Excel to estimate a cost function by regressing cost on output (Chapter 3). Try a linear specification (C = a + bq), a quadratic specification (C = a + bq + dq2), and a cubic specification (C = a + bq + dq2 + eq3). Based on the plotted regressions, which 191 specification would you recommend that Jill use? Would it make sense to use the Set Intercept option? If so, what value would you choose? (Hint: Put output in column A and cost in column B. To obtain quadratic and cubic cost specifications, select the Polynomial option from the Trendline menu and set Order at 2 for the quadratic specification and at 3 for the cubic function.) b. Generate the corresponding average cost data by dividing the known cost by output for each experimental output level. Estimate an average cost curve using the Trendline tool. Appendix 6 Long-Run Cost Minimization We can use calculus to derive the tangency rule, cost-minimization condition, Equation 6.9. The problem the firm faces in the long run is to choose labor, L, and capital, K, to minimize the cost of producing a particular level of output, q, given a wage of w and a rental rate of capital of r. The firm’s production function is q = f(L, K), so the marginal products of labor and capital are MPL(L, K) = 0f(L, K)/0L 7 0 and MPK = 0f(L, K)/0K 7 0. The firm’s problem is to minimize its cost of production, C, through its choice of labor and capital, min C = wL + rK, L,K subject to the constraint that a given amount of output, q, is to be produced: f(L, K) = q. (6A.1) Equation 6A.1 is the formula for the q isoquant. We can change this constrained minimization problem into an unconstrained problem by using the Lagrangian technique. The corresponding Lagrangian, ℒ, is ℒ = wL + rK - λ[ f (L, K) - q], where λ is the Lagrange multiplier. The first-order conditions are obtained by differentiating ℒ with respect to L, K, and λ and setting the derivatives equal to zero: 0ℒ/0L = w - λMPL(L, K) = 0, 0ℒ/0K = r - λMPK(L, K) = 0, 0ℒ/0λ = f(L, K) - q = 0. (6A.2) (6A.3) (6A.4) Using algebra, we can rewrite Equations 6A.2 and 6A.3 as w = λMPL(L, K) and r = λMPK(L, K). Taking the ratio of these two expressions, we obtain MPL(L, K) w = , r MPK(L, K) (6A.5) which is the same as Equation 6.9. This condition states that cost is minimized when the ratio of marginal products is the same as the factor price ratio, w/r. 192 Firm Organization and Market Structure I won’t belong to any organization that would have me as a member. —Groucho Marx 7 Many managers, salespeople, and other employees who receive an annual bonus based on the firm’s performance this year may have an incentive to take actions that increase the firm’s profit this year but reduce profits in future years. Many dramatic examples of such behavior occurred in the last few years leading up to 2007, when banks seemed to go crazy issuing Clawing Back collateralized debt obligations (CDOs). Bonuses Banks and other financial firms collected mortgages of varying qualities, sorted them by quality (risk of default) into groups called tranches, and sold a CDO for each tranche. A CDO is a promise to pay the mortgage cash flows to the investors who buy the CDO. If the financial firm does not have enough money to cover the amount owed to all investors due to mortgage defaults, then those investors owning CDOs for the lowest tranches are not paid. To offset this greater risk, lower tranches sold for lower prices initially. Mortgage brokers were rewarded for bringing in large numbers of new mortgages to serve as the basis for new CDOs, and the companies threw accepted lending practices out the window. They provided mortgages to borrowers with bad financial records who put no money down on their houses. In the San Francisco Bay area, 69% of families whose owner-occupied homes were in foreclosure had put down 0% at the time of purchase, and only 10% had made the traditional 20% down payment in the first nine months of 2007. Both home owners and speculators were enticed to take out new mortgages with very low (subprime) initial mortgage rates that adjusted over time. Perhaps bank managers expected that the price of housing would rise forever, so that defaults would be manageable. However, the housing market tanked in 2007, sending housing prices into a free fall, so refinancing became nearly impossible. As interest rates on adjustable-rate mortgages rose, mortgage defaults skyrocketed, and CDOs lost most of their value. Merrill-Lynch & Co. provided a prime example of how issuing such CDOs could create serious problems. In the years prior to 2007, Merrill advertised that it was the “#1 global underwriter of CDOs.” As an underwriter, Merrill helped banks We’re now tying annual executive bonuses and other issuers of CDOs sell those CDOs, often purchasing to performance. You owe us $100,000. the CDOs from issuers before reselling them to investors. In M anagerial P roblem 193 194 CHAPTER 7 Firm Organization and Market Structure 2006–2007, Merrill was the lead underwriter on 136 CDO deals for $93 billion, from which Merrill made $800 million in underwriting fees. However, Merrill was unable to resell all the CDOs it had purchased, which would not have been a problem if CDO prices had remained stable or rose. When the CDO market started to collapse in mid-2007, Merrill suffered large losses on its holdings of CDOs and its underwriting fees also disappeared. Because of its managers’ reckless practices, Merrill lost over $36 billion in 2007 and 2008, which more than offset all its earnings from 1997 through 2006. Merrill CEO Stanley O’Neal earned “only” $1.2 million in 2007, but over his six previous years as CEO at Merrill he had earned a total of $157.7 million. Neither O’Neal nor Merrill’s other managers had to give back any of their prior earnings. Indeed, most Merrill senior managers received large bonuses in 2007. In 2006, only 18% of Fortune 100 companies had a publicly disclosed clawback policy, where the firm could reclaim payments to managers if those managers’ earlier actions caused later losses. By 2012, 87% had such a policy. Moreover, Wall Street firms have increasingly shifted bonuses from cash to deferred payments, which reflect the lower stock value if the company does badly later. Does evaluating a manager’s performance over a longer time period lead to better management? H aving examined firms’ production and cost decisions in earlier chapters, we now turn to some of the firm’s other crucial decisions. Owners have to decide what objectives the firm should pursue, and they need to structure incentives to induce managers to pursue these objectives. Managers need to decide which stages of production the firm should perform and which to leave to others. We also consider how market characteristics such as the number of rivals affect a firm’s decisions. Throughout this book, we discuss “how firms behave” or “the firm’s decision.” Obviously, firms are not conscious entities that make decisions—it is the people within firms who make decisions on behalf of those firms. The main reason we use this short cut is that we do not want to be distracted by discussing which person within the firm makes a particular decision for the firm. However, in this chapter (and in Chapter 15), we examine how owners and managers interact and how laws, transaction costs, market size, individual incentives, and other factors affect decisions owners and managers make. We start by examining the ownership and governance of firms, which affect the objectives a firm chooses to pursue. Although this book focuses on for-profit firms, the law permits and in some cases requires firms to pursue objectives other than maximizing profit. Even among for-profit firms, not all firms focus on maximizing profit because managers of the firm, who are not necessarily the firm’s owners, may decide to pursue another objective. If the owner of a firm is the manager, or if the manager and the owner have consistent objectives, no problems arise and we can largely ignore whether owners or managers make decisions. However, if their objectives are not aligned and the owner cannot completely control the behavior of the manager, then a conflict may arise. This conflict is one of many situations where a principal, such as an owner, delegates tasks to an agent, such as a manager. Such a conflict creates a special type of transaction cost called an agency cost. Many features of the firm’s organization can be viewed as attempts to minimize the associated agency cost. 7.1 Ownership and Governance of Firms 195 In the pursuit of their main goal, such as maximizing profit, owners and managers must make decisions about the nature of the firm, such as whether the firm produces needed inputs internally or buys them. Whether the firm makes or buys an input depends on the relative costs of these two approaches. These costs include agency costs as well as other transaction costs. The size of the market affects transaction and other costs, and thereby affects the make-or-buy decision. We show that as a market grows, firms typically change from producing their own inputs to buying them from others, but, as the market grows even larger, firms may revert to producing the inputs themselves. The size of the market affects not only individual firms’ organizational structure but also the overall structure of the market. A market’s structure is described by the number of firms, how easily they can enter or exit the market, their ability to set prices, whether they differentiate their products, and how the firms interact. Ma in Topics In this chapter, we examine five main topics 1. Ownership and Governance of Firms: Laws that affect how businesses are organized also affect who makes decisions and the firm’s objective, such as whether it tries to maximize profit. 2. Profit Maximization: To maximize profit, any firm must make two decisions: how much to produce and whether to produce at all. 3. Owners’ Versus Managers’ Objectives: Differences in objectives between owners and managers affect the success of a firm. 4. The Make or Buy Decision: Depending on which approach is most profitable, a firm may engage in many sequential stages of production itself, participate in only a few stages and rely on markets for others, or use contracts or other means to coordinate its activities with those of other firms. 5. Market Structure: Markets differ as to the number of firms in the market, the ease of entry of new firms, whether firms produce identical products, how the firms interact, and the ability of firms to set prices. 7.1 Ownership and Governance of Firms A firm may be owned by a government, by other firms, by private individuals, or by some combination. In the United States and most other countries, laws affect how private firms are owned, how owners may govern them, and whether they pursue profits or not. Private, Public, and Nonprofit Firms Atheism is a non-prophet organization. —George Carlin Firms operate in the private sector, the public sector, or the nonprofit sector. The private sector— sometimes referred to as the for-profit private sector or for-profit sector— consists of firms that are owned by individuals or other nongovernmental entities and whose owners may earn a profit. Most of the firms that we discuss throughout this book—such as Apple, Heinz, and Toyota—belong to the private sector. In almost every country, this sector provides most of that country’s gross domestic product (a measure of a country’s total output). 196 CHAPTER 7 Firm Organization and Market Structure The public sector consists of firms and other organizations that are owned by governments or government agencies, called state-owned enterprises. An example of a public sector firm is the National Railroad Passenger Corporation (Amtrak), which is owned primarily by the U.S. government. The armed forces and the court system are also part of the public sector, as are most schools, colleges, and universities. The government produces less than a fifth of the total gross domestic product (GDP) in most developed countries, including Switzerland (9%), the United States (11%), Ireland (12%), Canada (13%), Australia (16%), and the United Kingdom (17%).1 The government’s share is higher in a few developed countries that provide many government services—such as Iceland (20%), the Netherlands (21%), and Sweden (22%)—or maintain a relatively large army, such as Israel (24%). The government’s share varies substantially in less developed countries, ranging from very low levels like Nigeria (4%) to very high levels like Eritrea (94%). Strikingly, a number of former communist countries such as Albania (20%) and China (28%) now have public sectors of comparable relative size to developed countries and hence rely primarily on the private sector for economic activity. The nonprofit sector consists of organizations that are neither government owned nor intended to earn a profit, but typically pursue social or public interest objectives. Literally, this sector should be called the nongovernment, not-for-profit sector, but this term is normally shortened to just the nonprofit sector. Well-known examples include Greenpeace, Alcoholics Anonymous, and the Salvation Army, along with many other charitable, educational, health, and religious organizations. According to the 2012 U.S. Statistical Abstract, the private sector created 75% of the U.S. gross domestic product, the government sector was responsible for 12%, and nonprofits and households produced the remaining 13%. Sometimes all three sectors play an important role in the same industry. For example, in the United States, Canada, the United Kingdom, and in many other countries, for-profit, nonprofit, and government-owned hospitals coexist. Similarly, while most schools and other educational institutions are government owned, many are not, including some of the most prominent U.S. universities such as Harvard, Stanford, and the Massachusetts Institute of Technology (MIT). These universities are often referred to as private universities. Most private universities are nonprofit organizations. However, some educational institutions, such as the University of Phoenix, are intended to earn profits and are part of the for-profit private sector. A single enterprise may be partially owned by a government and partially owned by private interests. For example, during the 2007–2009 Great Recession, the U.S. government took a partial ownership position in many firms in the financial and automobile industries. If the government is the dominant owner, it is normal to view the enterprise as part of the public sector. Conversely, if the government has only a small ownership interest in a for-profit enterprise, that enterprise would be viewed as part of the private sector. Organizations or projects with significant government ownership and significant private ownership are sometimes referred to as mixed enterprises or public-private partnerships. 1The data in this paragraph are from Alan Heston, Robert Summers, and Bettina Aten, Penn World Table Version 6.2, Center for International Comparisons of Production, Income, and Prices at the University of Pennsylvania, September 2006: pwt.econ.upenn.edu/php_site/pwt62/pwt62_form .php. Western governments’ shares increased markedly (but presumably temporarily) during the major 2008–2009 recession, when they bought parts or all of a number of private firms to keep them from going bankrupt. 7.1 Ownership and Governance of Firms Mini-Case Chinese State-Owned Enterprises 197 Many international corporations are thinking of entering the rapidly growing Chinese market, but they fear that the Chinese government will take actions that favor Chinese state-owned enterprises (SOEs). These fears may go away if China moves away from SOEs, but the role of SOEs in the future is still unclear. Over the last decade, China has reduced the number of SOEs; however, it has kept the largest ones. Chinese SOEs have always been large relative to private firms. In 1999, SOEs were 36% of Chinese industrial firms, yet they controlled nearly 68% of industrial assets. Since then, the Chinese government has allowed many small SOEs to go private or go bankrupt, while it continues to subsidize large SOEs. By 2011, SOEs were only 5.2% of the firms but still owned 42% of the industrial assets. Ownership of For-Profit Firms In this textbook, we focus on the private sector. The private sector has three main types of organizations: the sole proprietorship, the partnership, and the corporation. Sole proprietorships are firms owned and controlled by a single individual. Partnerships are businesses jointly owned and controlled by two or more people operating under a partnership agreement. Corporations are owned by shareholders, who own the firm’s shares (also called stock). Each share (or unit of stock) is a unit of ownership in the firm. Therefore, shareholders own the firm in proportion to the number of shares they hold. The shareholders elect a board of directors to represent them. In turn, the board of directors usually hires managers who manage the firm’s operations. Some corporations are very small and have a single shareholder. Others are very large and have thousands of shareholders. The legal name of a corporation often includes the term Incorporated (Inc.) or Limited (Ltd) to indicate its corporate status. Publicly Traded and Closely Held Corporations. Corporations may be either publicly traded or closely held. The term public in this context has a different meaning than its use in the term public sector. A publicly traded corporation is a corporation whose shares can be readily bought and sold by the general public. The shares of most publicly traded corporations trade on major organized stock exchanges, such as the New York Stock Exchange, the NASDAQ (National Association of Securities Dealers Automated Quotations), the Tokyo Stock Exchange, the Toronto Stock Exchange, or the London Stock Exchange. For example, IBM shares can be readily bought and sold on the New York Stock Exchange. The stock of a closely held corporation is not available for purchase or sale on an organized exchange. Typically its stock is owned by a small group of individuals. The stock of a closely held corporation is sometimes referred to as private equity. The transition from closely held to publicly traded status is often an important step in the evolution of a corporation. In making the transition from privately held to publicly traded status, the closely held firm will make an initial public offering (or IPO) of its shares on an organized stock exchange. This IPO is a way to raise money for the firm. For example, Facebook’s IPO in 2012 raised $16 billion for the firm. This ability to raise money by issuing stock is one major advantage of going public. However, a major disadvantage from the 198 CHAPTER 7 Firm Organization and Market Structure point of view of the original owners is that ownership of the firm becomes broadly distributed, possibly causing the original owners to lose control of the firm. It is also possible for a publicly traded firm to go private and convert to closely held status. Such a change occurs when a small group of shareholders—typically managers of the firm—buy all or most of the shares held by the general public and take the corporation out of any organized exchanges where its stock previously traded. Toys Us is one of many well-known companies that went private recently along with many others: Burger King went private in 2010; J. Crew, Warner Music, and the Priory Group (Europe) in 2011; P.F. Chang’s, Knology, and Payless ShoeSource in 2012; and American Greeting Corp. in 2013. Liability. Traditionally, the owners of sole proprietorships and partnerships were fully liable, individually and collectively, for any debts of the firm. In contrast, the owners of a corporation are not personally liable for the firm’s debts; they have limited liability: The personal assets of the corporate owners cannot be taken to pay a corporation’s debts even if it goes into bankruptcy. Because of the limited liability of corporations, the most that shareholders can lose is the amount they paid for their stock, which typically becomes worthless if the corporation goes bankrupt. Changes in the laws in many countries have allowed a sole proprietorship or a partnership to obtain the advantages of limited liability by becoming a limited liability company (LLC).2 These LLC firms can otherwise do business as usual and need not adopt other aspects of the corporate form such as filing corporate tax returns. The precise regulations that apply to LLCs vary from country to country, and from state to state within the United States. Adopting the LLC form has some costs that many firms are not willing to incur, including registration fees, and firms in some industries are not eligible. Therefore, traditional sole proprietorships and partnerships with unlimited personal liability for the owners remain very common. However, the LLC form has significantly extended the availability of limited liability.3 Firm Size. The purpose of limiting the liability of owners of corporations was to allow firms to raise funds and grow larger than was possible when owners risked everything they owned on any firm in which they invested. Consequently, most large firms were (and still are) corporations. According to the 2012 U.S. Statistical Abstract, U.S. corporations are responsible for 81% of business receipts and 58% of net business income even though they are only 18% of all nonfarm firms. Nonfarm sole proprietorships are 72% of firms but make only 4% of the sales revenue and earn 15% of net income. Partnerships are 10% of firms, account for 15% of revenue, and make 27% of net income. As these statistics illustrate, larger firms tend to be corporations and smaller firms are often sole proprietorships. This pattern reflects a natural evolution in the life cycle of the firm, as an entrepreneur may start a small business as a sole proprietorship and then incorporate as the firm’s operations expand. Indeed, successful corporations typically expand, and a relatively small number of corporations account for most of the revenue and income in the U.S. economy. 2In the United States, a few states had longstanding provisions for LLCs, but national acceptance and standardization of this form dates from the Uniform Limited Liability Company Act of 1996. 3Forming a limited partnership has become an alternative method for a partnership to gain the advantages of limited liability. Such firms are owned in whole or in part by limited partners, whose financial liability is limited in the sense that they cannot lose more than the amount of their investment. Limited partnerships may also have one or more general partners who, like sole proprietors, are personally responsible for the firm’s debts. 7.2 Profit Maximization 199 Eighty-one percent of all corporations earn less than $1 million a year, and they account for only 3% of corporative revenue (U.S. Statistical Abstract, 2012). In contrast, less than 1% of all corporations earn over $50 million, but they make 77% of total corporate revenue. In 2012, ExxonMobil was the U.S. corporation with the largest worldwide revenue. Its revenue of $434 billion exceeded the annual GDP of fairly large countries, such as Austria ($301 billion) and Greece ($216 billion).4 Firm Governance In a small private sector firm with a single owner-manager, the governance of the firm is straightforward: the owner-manager makes the important decisions for the firm. In contrast, governance in a large modern publicly traded corporation is more complex. The shareholders own the corporation. However, most shareholders play no meaningful role in day-to-day decision making or even in long range planning in the firm and therefore do not control the firm in any meaningful sense. Many people own shares in corporations like Microsoft and Sony, but these individuals have no influence on and little knowledge of these firms’ day-to-day managerial decisions. Many of the ownership rights of shareholders are delegated to a board of directors that is elected by the shareholders, often referred to simply as the board. The board of a large publicly traded corporation normally includes outside directors, who are not employed as managers by the corporation, and inside directors, such as the chief executive officer (CEO) of the corporation and other senior executives. Current directors of major corporations include former U.S. Vice President Al Gore (Apple), football star Lynn Swann (Heinz), and author and self-help guru Deepak Chopra (Men’s Warehouse), among many others. 7.2 Profit Maximization The managers of all types of firms pursue goals. Managers of government agencies, charitable organizations, and other nonprofit organizations are supposed to take actions that benefit specific groups of people. We assume that most owners of private-sector firms want to maximize their profits, which is the reason why private-sector firms are called for-profit businesses. However, managers may not share the owners’ objective—particularly if their compensation is not tied closely to the firm’s profit. In this section, we discuss how a firm maximizes its profit. In the next section, we discuss the factors that might lead the manager of a firm to pursue another objective and some of the methods that owners use to ensure that managers try to maximize profit. Profit A firm’s profit, π, is the difference between a firm’s revenues, R, and its cost, C: π = R - C. If profit is negative, π 6 0, the firm makes a loss. 4Fortune Magazine annually provides a list of the largest corporations: www.forbes.com/sites/ scottdecarlo/2012/04/18/the-worlds-biggest-companies. GDP data are from the IMF for 2011. 200 CHAPTER 7 Firm Organization and Market Structure Measuring a firm’s revenue from the sale of its product is straightforward: Revenue is price times quantity. Measuring cost is more challenging. From the economic point of view, the correct measure of cost is the opportunity cost: the value of the best alternative use of any input the firm employs. As discussed in Chapter 6, the full opportunity cost of inputs used might exceed the explicit or out-of-pocket costs recorded in financial accounting statements. The reason that this distinction is important is that a firm may make a serious mistake if it does not measure profit properly because it ignores some relevant opportunity costs. Two Steps to Maximizing Profit Because both the firm’s revenue and cost vary with its output, q, the firm’s profit also varies with output: π(q) = R(q) - C(q), (7.1) where R(q) is its revenue function and C(q) is its cost function. A firm decides how much output to sell to maximize its profit, Equation 7.1. To maximize its profit, any firm must answer two questions: ◗ Output decision: If the firm produces, what output level, q, maximizes its profit or minimizes its loss? ◗ Shutdown decision: Is it more profitable to produce q or to shut down and produce no output? The profit curve in Figure 7.1 illustrates these two basic decisions. This firm makes losses at very low and very high output levels and positive profits at moderate output levels. The profit curve first rises and then falls, reaching a maximum profit of π* when its output is q*. As this profit level is positive, the firm chooses to produce output q* rather than shut down and earn no profit. Output Rules. A firm can use one of three equivalent rules to choose how much output to produce. These rules are just three different ways of stating essentially the same thing. The most straightforward rule is: Output Rule 1: The firm sets its output where its profit is maximized. By setting its output at q*, the firm maximizes its profit at π*, where the profit curve reaches its peak. π, Profit F IG U RE 7. 1 Maximizing Profit Δπ = 0 π* Profit Δπ > 0 Δπ < 0 1 0 1 q* q, Units per day 7.2 Profit Maximization 201 If the firm knows its entire profit curve in Figure 7.1, it sets its output at q* to maximize its profit at π*. Even if the firm does not know the exact shape of its profit curve, it may be able to find the maximum by experimenting. The firm slightly increases its output. If profit increases, the firm increases the output more. The firm keeps increasing output until profit does not change. At that output, the firm is at the peak of the profit curve. If profit falls when the firm first increases its output, the firm tries decreasing its output. It keeps decreasing its output until it reaches the peak of the profit curve. What the firm is doing is experimentally determining the slope of the profit curve. The slope of the profit curve is the firm’s marginal profit: the change in the profit the firm gets from selling one more unit of output, Δπ/Δq, where Δq = 1. In Figure 7.1, the marginal profit or slope of the profit curve is positive when output is less than q*, zero when output is q*, and negative when output is greater than q*. Thus, Output Rule 2: A firm sets its output where its marginal profit is zero. A third way to express this profit-maximizing output rule is in terms of cost and revenue. The marginal profit depends on a firm’s marginal cost and marginal revenue. A firm’s marginal cost (MC) is the amount by which a firm’s cost changes if it produces one more unit of output: MC = ΔC/Δq, where ΔC is the change in cost when Δq = 1. Similarly, a firm’s marginal revenue (MR) is the change in revenue it gets from selling one more unit of output: ΔR/Δq, where ΔR is the change in revenue when Δq = 1. Provided MR is positive at output q, the firm earns more revenue by selling more units of output, but the firm also incurs an additional cost, MC(q), which must be deducted from MR(q) to determine the net effect on marginal profit. The change in the firm’s profit is Marginal profit (q) = MR(q) - MC(q). Does it pay for a firm to produce one more unit of output? If the marginal revenue from this last unit of output exceeds its marginal cost, MR(q) 7 MC(q), the firm’s marginal profit is positive, MR(q) - MC(q) 7 0, so it pays to increase output. The firm keeps increasing its output until it is producing q, where its marginal profit(q) = MR(q) - MC(q) = 0. There, its marginal revenue equals its marginal cost: MR(q) = MC(q). If the firm produces more output where its marginal cost exceeds its marginal revenue, MR(q) 6 MC(q), the extra output reduces the firm’s profit. Thus, a third, equivalent rule is: Output Rule 3: A firm sets its output where its marginal revenue equals its marginal cost: MR(q) = MC(q). (7.2) Using Calculus Maximizing Profit We can use calculus to derive the condition that marginal revenue must equal marginal cost at the output level that maximizes profit. Using calculus, we define marginal revenue as the derivative of revenue with respect to output: MR(q) = dR(q) dq . The derivative dR(q)/dq is the limit of ΔR(q)/Δq as Δq gets very small. Our earlier definition of marginal revenue, ΔR(q)/Δq for Δq = 1, is nearly equivalent to the calculus definition if Δq = 1 is a “very small” change. Similarly, marginal cost is the derivative of cost with respect to output, MC(q) = dC(q)/dq (Chapter 6). 202 CHAPTER 7 Firm Organization and Market Structure To maximize profit in Equation 7.1, π(q) = R(q) - C(q), the firm operates at the quantity q where the derivative of profit with respect to quantity is zero: dπ(q) dq = dR(q) dq dC(q) - dq = MR(q) - MC(q) = 0. (7.3) The left side of Equation 7.3, dπ/dq, is the firm’s marginal profit. This result shows that marginal profit equals the difference in marginal revenue and marginal cost. Because this profit-maximizing condition requires that MR(q) - MC(q) = 0, it follows that the firm maximizes its profit when it chooses output such that MR(q) = MC(q), which is the same condition as in Equation 7.2. Q& A 7.1 If a firm’s revenue function is R(q) = 120q - 2q2 and its cost function is C(q) = 100 + q2, what output level maximizes its profit? Answer 1. Determine the marginal revenue and marginal cost by differentiating the revenue and cost functions. The firm’s marginal revenue is dR(q)/dq = 120 - 4q. Its marginal cost is dC(q)/dq = 2q. 2. Equate the marginal revenue and marginal cost expressions to determine the output that maximizes profit. Setting the marginal revenue equal to the marginal cost, we find that 120 - 4q = 2q. Solving for q, we learn that the profit-maximizing output is q = 20. 3. Alternatively, determine the profit function and then differentiate the profit function to find the maximum. The profit function is π(q) = R(q) - C(q) = [120q - 2q2] - [100 + q2] = 120q - 3q2 - 100. Taking the derivative of the profit function with respect to quantity (the marginal profit) and setting it equal to zero, we learn that dπ(q)/dq = 120 - 6q = 0. Consequently, the profit-maximizing output is q = 20. Ma nagerial I mplication Marginal Decision Making One of the most important implications of economics is that marginal analysis is very valuable to managers. If a manager knows the entire profit function (as in Figure 7.1), then it’s easy to choose the profit-maximizing output. However, many managers are uncertain about what profit would be at output levels that differ significantly from the current level. Such a manager can use marginal reasoning to maximize profit. By experimenting, the manager can determine if increasing output slightly raises profit—that is, the firm’s marginal profit is positive (or, equivalently, its marginal revenue is greater than its marginal cost). If so, the manager should continue to increase output until the marginal profit is zero (marginal revenue equals marginal cost). Similarly, if marginal profit is negative, the manager should decrease output until marginal profit is zero.5 our examples, this marginal condition (MR = MC or dπ/dq = 0) is met at only one output level, where profit is maximized. However, it is possible to have more than one local profit maximum, each of which satisfies the marginal condition. This marginal condition will also be satisfied if there is a positive output level where profit is minimized. If the marginal condition holds at more than one quantity, the one with the highest profit is the global profit maximum. 5In 7.2 Profit Maximization 203 Shutdown Rules. Producing the output level q such that MR(q) = MC(q) is a necessary condition to maximize profit if the firm produces a positive output level. However, the firm might make losses even at the best possible positive output (although a smaller loss than at other positive outputs). Should the firm shut down if its profit is negative? Surprisingly, the answer is “It depends.” The general rule, which holds for all types of firms in both the short run and in the long run, is: Shutdown Rule 1: The firm shuts down only if it can reduce its loss by doing so. In the short run, the firm has variable costs, such as for labor and materials, and fixed costs, such as from plant and equipment (Chapter 6). If the fixed cost is sunk, this expense cannot be avoided by stopping operations—the firm pays this cost whether it shuts down or not. Thus, the sunk fixed cost is irrelevant to the shutdown decision. By shutting down, the firm stops receiving revenue and stops paying the avoidable costs (Chapter 6), but it is still stuck with its fixed cost. Thus, it pays for the firm to shut down only if its revenue is less than its avoidable cost. Suppose that a firm’s weekly revenue is R = $2,000, its variable cost is VC = $1,000, and its fixed cost is F = $3,000, which is the price it paid for a machine that it cannot resell or use for any other purpose. This firm is making a short-run negative profit π (a loss): π = R - VC - F = $2,000 - $1,000 - $3,000 = -$2,000. If the firm shuts down, it still has to pay its fixed cost of $3,000, and hence it loses $3,000, which is a greater loss than the $2,000 it loses if it operates. Because its fixed cost is sunk, the firm should ignore it when making its shutdown decision. Ignoring the fixed cost, the firm sees that its $2,000 revenue exceeds its $1,000 avoidable, variable cost by $1,000, so it does not shut down. The extra $1,000 can be used to offset some of the fixed cost, reducing the firm’s loss from $3,000 to $2,000. However, if its revenue is only $500, it cannot cover its $1,000 avoidable, variable cost and loses an additional $500. When it adds this $500 loss to the $3,000 it must pay in fixed cost, the firm’s total loss is $3,500. Because the firm can reduce its loss from $3,500 to $3,000 by ceasing operations, it shuts down. (Remember the shutdown rule: The firm shuts down only if it can reduce its loss by doing so.) The firm’s variable costs are always avoidable: the firm only pays the variable costs if it operates. In contrast, the firm’s short-run fixed cost is usually unavoidable: the firm incurs the fixed cost whether or not it shuts down. Therefore, if the firm shuts down in the short run it incurs a loss equal to its fixed cost because it has no revenue (R = 0) or variable cost (VC = 0), so its profit is negative: π = R - VC - F = 0 - 0 - F = -F. If the firm operates and its revenue more than covers its variable cost, R 7 VC, then the firm does better by operating because π = R - VC - F 7 -F. Thus, the firm shuts down only if its revenue is less than its avoidable, variable cost: R 6 VC. In conclusion, the firm compares its revenue to only its avoidable, variable costs when deciding whether to stop operating. If the fixed cost is sunk, the firm pays this cost whether it shuts down or not. The sunk fixed cost is irrelevant to the shutdown decision. We usually assume that a fixed cost is sunk. However, if a firm can sell its capital for as much as it paid, its fixed cost is avoidable and should be taken into account when the firm is considering whether to shut down. A firm with a fully avoidable fixed cost always shuts down if it makes a short-run loss. If a firm buys a specialized piece of machinery for $1,000 that can be used only in its business but can be sold for scrap metal for $100, then $100 of the fixed cost is avoidable and $900 is sunk. Only the avoidable portion of fixed cost is relevant for the shutdown decision. 204 CHAPTER 7 Firm Organization and Market Structure In planning for the long run, all costs are avoidable because there are no sunk fixed costs: all capital and other inputs are adjustable in the long run. The firm can eliminate all costs by shutting down. Thus, in the long run, it pays to shut down if the firm faces any loss at all. As a result, we can restate the shutdown rule, which holds for all types of firms in both the short run and the long run, as: Shutdown Rule 2: The firm shuts down only if its revenue is less than its avoidable cost. Profit over Time Through most of this book, we examine a firm whose shareholders want it to maximize its profit in the current period. However, firms are typically interested in maximizing their profit over many periods. Often when one period is just like the others, this distinction in objectives is minor. However, in some situations the difference between maximizing the current period’s profit and long-run profit is important. For example, when Amazon, Netflix, and Groupon launched, each spent large sums of money on advertising, investing in product improvements, providing services below cost, and taking other actions to acquire as many loyal customers as possible. By doing so, they reduced their short-run profit—indeed, often running at a loss—in the hopes of acquiring larger long-run profits.6 Because money in the future is worth less than money today, the shareholders of a firm may value a stream of profits over time by calculating the present value, in which future profits are discounted using the interest rate (Appendix 7). Ma nagerial I mplication Stock Prices Versus Profit Many newspaper articles and business shows focus almost exclusively on the price of a share of the firm’s stock rather than on its annual profit. Does it follow that a manager should be more concerned about a firm’s stock price than its profit? It makes no difference if the manager’s objective is to maximize either measure if the stock price reflects the firm’s profit. The owner of stock in a corporation like Nokia or Starbucks has the right to share in the current and future profits of the firm. Therefore, the stock price reflects both current and future profits. The sum of the value of all outstanding shares in the firm is the stock market valuation of the firm. It is the present value investors place on the flow of current and future profits. If the firm earns an annual profit of π per year forever, the present value of that profit stream is π/i, where i is the interest rate (Appendix 7, Equation 7A.4). For example, if the firm earns $10 million a year forever and the interest rate is 10%, then the present value is $10/0.10 = $100 million. If shareholders expect this level of profit and interest rate to continue in the future and the firm issued one million shares of stock, then each share would sell for $100. If the firm’s profit were higher, then its present value would also be higher. For example, if the annual profit were known to be $11 million per year forever (instead of $10 million), then the firm’s present value would be $110 million and the value of each share would be $110. Thus, maximizing a constant profit flow maximizes the value of the firm and is therefore equivalent to maximizing the stock price. 6Indeed, Amazon’s stock price rose substantially over time, with the price in February 2013 nearly 13 times larger than when it was initially offered in 1997. 7.3 Owners’ Versus Managers’ Objectives 205 However, if a firm’s profit flow varies over time, then the link between a firm’s profit and its stock price is more complex and the stock price might be more relevant to managers than the current profit. Consider a firm that makes a major investment that causes it to suffer a loss this year but that results in higher profits in the future. If investors understand that the investment will pay off in the long run, the stock price rises after the investment is made. Thus, a manager who is concerned about a firm’s long-run profit stream may try to maximize the present value of profit or, equivalently, maximize the firm’s stock value, rather than concentrate on the profit this period. However, if investors are not well informed about the firm’s profit so that the stock price does not closely track the present value of profits, then maximizing the stock price is not equivalent to maximizing the present value of profits. 7.3 Owners’ Versus Managers’ Objectives The executive exists to make sensible exceptions to general rules. —Elting E. Morison Except for the smallest of firms, one person cannot perform all the tasks necessary to run a firm. In most firms, the owners of the firm have to delegate tasks to managers and other workers. A conflict may arise between owners who want to maximize profit and managers interested in pursuing other goals, such as maximizing their incomes or traveling in a company jet. A conflict between an owner (a principal) and a manager (an agent) may impose costs on the firm—agency costs—that result in lower profit for the firm. However, owners can take steps to minimize these conflicts, and market forces reduce the likelihood that a firm will deviate substantially from trying to maximize profit. Consistent Objectives No conflict between owners and managers arises if the owner and the manager have the same objective. To make their objectives more closely aligned, many firms use contingent rewards, so that the manager receives higher pay if the firm does well. Contingent Rewards. Owners may give managers pay incentives to induce them to work hard and to maximize profit. If good performance by managers is observable, the owner can reward it directly. However, the owners of large corporations—the shareholders—usually cannot observe the performance of individual managers. Owners often provide alternative incentive schemes to managers and others whose productivity is difficult to quantify, especially those who work as part of a team. Such workers may be rewarded if their team or the firm does well in general. Frequently, year-end bonuses are based on the firm’s profit or increases in the value of its stock. A common type of incentive is a lump-sum year-end bonus based on the performance of the firm or a group of workers within the firm. Another incentive is a stock option, which gives managers (and increasingly other workers) the option to buy a certain number of shares of stock in the firm at a prespecified exercise price within a specified time period. If the stock’s market price exceeds the 206 CHAPTER 7 Firm Organization and Market Structure exercise price during that period, an employee can exercise the option—buy the stock—and then sell it at the market price, making an immediate profit. But if the stock’s price stays below the exercise price, the option becomes worthless.7 Steve Jobs, CEO and co-founder of Apple, received a salary of only $1 per year until his retirement in 2011, but he also received stock options worth hundreds of millions of dollars. Profit Sharing. If profit is easily observed by the owner and the manager and both want to maximize their own earnings, the agency problems can be avoided by paying the manager a share of the firm’s profit. Typically, rather than paying managers a share of the profit directly, their earnings are based on the company’s stock price, which rises as the firm’s profit increases. Frydman and Saks (2008) found that large U.S. firms have increasingly linked executive compensation to the firm’s financial performance over time. They estimated that by 2005 over 70% of firms provided annual stock options to their top three executives, compared to virtually none in 1950 and about 50% in 1970. On average in 2009, 75% of total compensation of a chief executive at S&P 500 firms came from incentives: bonuses (2%), nonequity incentive plan compensation (19%), option awards (25%), and stock awards (28%).8 Such incentive-based compensation is more common in the United States than in most other countries. According to Conyon and Muldoon (2006), U.S. CEO incentives were much stronger than those in the United Kingdom. The share of compensation from salary was only 31% in the United States but 44% in the United Kingdom. Bonuses were comparable: 20% in the United States and 22% in the United Kingdom. The biggest difference was that the stock option share of CEO compensation in the United States, 32%, was nearly three times that in the United Kingdom, 11%. If the manager is paid a specified fraction of the firm’s profit, and both the manager and owners care only about financial returns, then the agency problem is avoided because the objectives of the manager and the owners are aligned. Both parties want to maximize total profit. The output level that maximizes total profit also maximizes any fixed fraction of total profit. In Figure 7.2, the manager (agent) earns one-third of the joint profit of the firm and the shareholders (principals) receive two-thirds. The figure shows that the output level, q*, maximizes the profits of both the manager and the shareholders.9 The next Q&A analyzes an alternative compensation scheme. 7A stock option might have unintended negative consequences if it gives a manager an incentive to increase the firm’s short-run stock price at the expense of future stock prices. After all, in the long run, an employee might not even be around and therefore might place excessive emphasis on the short run. 8An option award gives the executive the option to buy an amount of stock at a specified price up to a specified date. A stock award grants an executive stock directly. The statistics are from www.aflcio .org/corporatewatch/paywatch/pay (viewed February 26, 2013). 9To determine where profit is maximized using calculus, we differentiate the profit function, π(q), with respect to output, q, and set that derivative, which is marginal profit, equal to zero: dπ(q)/dq = 0. The quantity that maximizes the manager’s share of profit, 13 π(q), is determined by d 13 π(q)/dq = 13 dπ(q)/dq = 0, or dπ(q)/dq = 0. That is, the quantity at which the manager’s share of profit reaches a maximum is determined by the same condition as the one that determines that total profit reaches a maximum. 7.3 Owners’ Versus Managers’ Objectives 207 If the manager gets a third of the total profit, 13 π, then the manager sets output at q*, which maximizes the manager’s share of profit. The firm’s owners receive 23 π, which is the vertical difference between the total profit curve and the agent’s earnings at each output. Both total profit and the owner’s share of profit are also maximized at q*. Total and manager’s profits, $ F IG U RE 7. 2 Profit Sharing π, Total profit 1 – π, Manager’s profit 3 0 Total and manager’s profits, $ Q&A 7.2 0 q* q, Output per month Peter, the owner, makes the same offer to the manager at each of his stores: “At the end of the year, give me $100,000 and you can keep any additional profit.” Ann, a manager at one of the stores, gladly agrees, knowing that the total profit at the store will substantially exceed $100,000 if it is well run. If she is interested in maximizing her earnings, will Ann act in a manner that maximizes the store’s total profit? Answer 1. Draw a diagram showing the total profit curve and use it to derive Ann’s profit curve. The figure shows that the total profit curve is first increasing and then decreasing as output rises. Ann, the manager, receives the total profit minus $100,000, so at every quantity, her profit is $100,000 less than the store’s total profit. Thus, her profit curve is the original curve shifted down by $100,000 at every quantity. The figure shows only that part of Ann’s profit curve where her E profit is positive. 2. Determine the quantity that maximizes π, Total profit Ann’s profit and check whether that quantity also maximizes total profit. In the figure, Ann’s profit is maximized at point E* where output is q*. At that quantity, total profit is also maximized at point E. Because the manager’s curve E * π – $100,000, Manager’s profit is the total profit curve shifted straight down, the quantity that maximizes one curve must maximize the other. Thus, if Ann wants to maximize her earnings, she will work to maximize the store’s q, Output per year q* profit. 208 CHAPTER 7 Firm Organization and Market Structure Conflicting Objectives Unfortunately, owners and managers have conflicting objectives in some firms. A manager is especially likely to pursue an objective other than profit if the manager’s compensation system rewards the manager for something other than maximizing profit. Moreover, even if the owner offers to share the profit with the manager, a manager who pursues an objective other than purely maximizing personal earnings, such as wanting to avoid working hard, will not maximize profit. Revenue Objectives. It is not always feasible to tie a manager’s compensation to profit, because profit may not be observed by everyone or because the owner or the manager can manipulate the reported profit.10 For example, if the manager can allocate reported costs to a future year, the manager can increase reported profit this year. Consequently, many firms tie a manager’s compensation to an objective other than current profit. As the Mini-Case “Determinants of CEO Compensation” (in Chapter 3) documents, many boards link their chief executive officer’s compensation to the size of the firm as measured by sales, the firm’s revenue. However, if executive compensation is primarily determined by the firm’s revenue, managers prefer to maximize revenue rather than profit. Figure 7.3 shows the revenue or sales curve as well as the profit curve for a firm.11 If the owner’s agent, the manager, is paid a share of revenue, the manager sets output at q = 5, where profit is 5 and revenue is 25. This output level exceeds the output that maximizes profit, q = 3, where profit is 9 and revenue is 21. If the manager’s earnings are in proportion to revenue, the manager wants the firm to produce q = 5 units of output. However, profit is maximized where q = 3 units are produced. Sales, Profit per hour F IG U RE 7. 3 Revenue Maximization 25 21 Revenue 9 5 Profit 0 3 5 q, Output per hour 10Authors normally receive royalties based on revenue rather than profit. They will not agree to compensation based on profit because they fear that the publisher would be able to reduce reported profit by allocating common costs associated with publishing all books to their particular book. Similarly, top movie stars and directors insist on a percentage of sales rather than profit because studios have been notorious for reporting such implausibly high costs that even blockbuster movies apparently made losses. this figure, the firm faces a linear inverse demand curve of p = 10 - q and a cost function of C = 4q. Consequently, the firm’s revenue is R = 10q - q2 and its profit is π = R - C = 6q - q2. 11In 7.3 Owners’ Versus Managers’ Objectives 209 While rewarding a manager solely based on revenue would cause problems, most corporations mix revenue incentives with other incentives, so as to induce the manager to maximize profit. The Mini-Case “Determinants of CEO Compensation” in Chapter 3 shows that a typical CEO’s compensation is a weighted average of a measure of revenue, profit, shareholders’ returns, and other measures. To the degree that more weight is placed on profit than on revenue, the manager is more likely to set output close to the profit-maximizing output level. Some boards that reward managers for increasing revenue may do so even though they are interested in maximizing long-run profit. They may believe that the profit measure reflects short-run profit and that long-run profit will be higher if the firm becomes larger in the short run, perhaps due to learning by doing (Chapter 6) or obtaining more loyal customers (as Amazon did). Revenue, $ Q& A 7.3 MR > 0 0 How does a manager set output to maximize revenue? Describe the role of marginal revenue in your analysis. Answer MR = 0 1. Draw a diagram showing the sales or revenue curve and identify the quantity at which it Revenue reaches a peak. The figure shows a singlepeak revenue curve. This curve reaches its maximum at an output of q*. MR < 0 2. Use marginal revenue to determine when the revenue curve reaches its peak. The slope of the revenue curve is marginal revenue, MR. Where the curve slopes up, MR is positive. Where it slopes down, MR is negative. Where the revenue curve reaches its maximum, MR is zero.12 Thus, the manager sets production at q* to q, Output per hour q* maximize revenue. Other Objectives. If the manager’s utility or well-being depends on personal effort as well as personal earnings, then even receiving a share of profit may not be a sufficient incentive for the manager to maximize the firm’s profit. Also, a manager who receives a fixed salary or other compensation that is not tied to the firm’s performance and who values leisure may not work hard enough to maximize the firm’s profit. If a board reacts by insisting that a certain profit target be achieved, a manager may satisfice by merely achieving results that are “good enough” rather than trying to maximize profit. Another possibility—particularly if executive compensation is not tied closely to profit—is that senior executives may pursue their own values or social objectives instead of maximizing profit. For example, corporations often make large 12To determine where revenue is maximized using calculus, we differentiate the revenue function, R(q), with respect to output, q, and set that derivative, which is marginal revenue, equal to zero: MR = dR(q)/dq = 0. 210 CHAPTER 7 Firm Organization and Market Structure contributions to sports franchises, hospitals, universities, environmental projects, disadvantaged groups, or other causes. Although it is difficult to argue that such recipients are unworthy, these managers are pursuing social policy with shareholders’ money. If shareholders want to donate money for a new football stadium or a new hospital, they can do so directly; thus, they might not want managers making such decisions for them. However, the owners of some firms (such as McDonalds, Unilever, and many others) explicitly authorize a firm’s managers to spend limited amounts to pursue particular environmental or other social objectives, even though such actions may reduce the firms’ profits. Although a manager who is solely interested in personal gain may steal from a firm, we hope that relatively few managers are that dishonest. Nonetheless, many managers believe it is appropriate to treat themselves to a variety of perquisites (perks)—benefits beyond their salary—of dubious value to the firm. It is perfectly appropriate for a corporation to provide a manager with health or various other benefits. If the firm reduces the manager’s salary by the cost of such benefits, then these benefits do not harm the firm’s bottom line. A firm might want to provide a flashy perk such as a luxurious office to impress clients or a chauffeured limo that saves a manager’s time and increases profit. Nonetheless, some managers unilaterally grant themselves perks that come out of the firm’s profit with little or no tangible advantage to the firm. Mini-Case Company Jets Some corporations allow the chief executive officer (CEO) to make personal use of the company’s plane—for example, to play golf at a distant course. In 2011, the Wall Street Journal reported that, based on a review of the flight records of dozens of corporate jets over a four-year period, more than half of their trips were to or from resort destinations, and usually to locations where executives owned homes.13 If the corporation reduces the CEO’s earnings so that the CEO is effectively paying for this privilege, providing the aircraft should have no effect on the firm’s bottom line or its stock’s value. On the other hand, such a perk reduces a firm’s profit if managers are directing some of the firm’s profit into their own pockets without providing compensating service. Moreover, if workers react adversely to managers’ perks, morale may fall and shirking and unethical behavior may increase. If so, we would expect the firm’s profit and stock value to fall. 13These perks are often a large share of an executive’s compensation. In a 2012 filing, Facebook reported that Mark Zuckerberg, its CEO, had a compensation package including $483,333 in salary, a $220,500 bonus, and $783,529 in “other compensation,” which includes $692,679 for “personal use of aircraft chartered in connection with his comprehensive security program and on which family and friends flew.” 7.3 Owners’ Versus Managers’ Objectives 211 According to Yermack (2006), when firms first disclose a CEO’s jet plane perquisites, shareholders react very negatively, causing the firm’s stock price to fall by 1.1% on average. Moreover, the long-run effect of such disclosures is to reduce average shareholder returns by more than 4% below market benchmarks annually—a large gap that greatly exceeds the cost of resources consumed. Although perks may be given to reward excellent work by managers, large perks often indicate weak governance by boards. Companies disclosing a plane perk are more likely to take extraordinary accounting write-offs and to report quarterly earnings per share significantly below analyst estimates. Monitoring and Controlling a Manager’s Actions If the owner’s and manager’s objectives conflict, the owner may try to monitor or control the manager’s behavior. Monitoring is difficult if the owner cannot easily observe the actions of the manager and if the profit or other payoff from these actions is subject to uncertainty. Moreover, controlling the manager’s actions is difficult if the parties cannot write an enforceable contract. If the owner and manager work side by side, monitoring the manager is easy. However, the cost of monitoring the manager’s effort is sometimes prohibitively high. Usually the owner does not want to have to shadow the manager all day to ensure that the manager is working hard. Installing a time clock might show that the manager was at work, but it does not show that the manager was working hard. In any case, it is typically difficult to determine if a manager who must engage in a complex set of actions is working well. When direct monitoring of a manager’s actions is impractical, the owner may be able to use an indirect method to monitor, as we discuss in Chapter 15. To minimize agency costs, most corporations set rules that govern the relationship between the board and the senior executives. Senior executives are usually restricted in their ability to carry out activities outside the firm that are related to their duties at the firm. Many are required to disclose to the board various actual or potential conflicts of interest that might arise. Similarly, most corporations set rules that govern the board of directors to further reduce the likelihood of agency problems between the board and the shareholders. For example, the rules may require the board to have outside directors: directors who are not the firm’s managers. The rules also specify the nature and frequency of elections to the board and the rights of shareholders to vote on important decisions and to propose various actions at shareholder meetings. Unfortunately, it is difficult to specify or legally enforce what constitutes appropriate effort on the part of the board. Moreover, in most corporations, although board members must be elected by shareholders, new board members are nominated by the existing board. Although some shareholders sue boards, such lawsuits are costly to pursue and rarely solve the associated agency problems.14 14According to Briody (2001), the average payout in shareholder lawsuits that are settled is approximately only 5% of the associated financial loss to shareholders. In addition, many lawsuits are unsuccessful and most alleged or suspected board misconduct never gives rise to lawsuits. 212 CHAPTER 7 Firm Organization and Market Structure The 2007–2009 financial crisis induced some shareholders to be more vigilant. A new movement to give shareholders’ a say on pay (SOP) going to upper management gained momentum.15 For example, Apple’s shareholders passed an SOP resolution in 2009. Similarly, in 2009 the Bank of America added four outside directors with banking and finance experience to its board to improve its corporate governance. In 2012, Citigroup shareholders rejected a $15 million pay package for its chief executive, Vikram S. Pandit, on the grounds that it lacked “rigorous goals to incentivize improvement in shareholder value.” The compensation package of his successor was smaller and more closely tied to the firm’s performance relative to that of other large banks.16 The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 requires publicly traded companies to have shareholders vote periodically (at least once every three years) on the compensation going to senior executives. The vote is nonbinding, so a negative vote does not necessarily block the compensation. However, failed SOP votes create significant problems for a firm, including negative publicity and greater legal vulnerability to shareholder lawsuits. The U.S. Securities and Exchange Commission released rules on implementing SOP in 2011. However, in the first year of SOP requirements, among the thousands of U.S. public companies, only about 2% of SOP votes had a majority of shareholders vote against the planned compensation packages. Takeovers and the Market for Corporate Control Competition is the keen cutting edge of business, always shaving away at costs. —Henry Ford Many owners provide adequate monitoring to keep managers on the straight and narrow. However, we generally assume that firms try to maximize profit because of the survivor principle as well as the market for corporate control. According to the survivor principle, in highly competitive markets, the only firms that survive are those that are run so as to maximize profit. Firms that fail to maximize profit lose money and go out of business. Even in less competitive markets, managers can be disciplined through the market for corporate control, where outside investors use the stock market to buy enough shares to take over control of an underperforming publicly traded firm. An outsider may profit by seizing control of a company in which the current managers are doing a poor job—undertaking unprofitable projects and spending money on their own comfort and compensation—with little profit going to the shareholders in the form of dividends or capital gains. If the acquiring firm can convince enough shareholders that profit will rise after a takeover, the shareholders can vote out the existing board and management and vote in the one the acquiring firm recommends. For example, Sophia is the manager of an underperforming company. She knows that a well-known investor or corporate raider (such as Carl Icahn or T. Boone Pickens) has been buying up shares of the firm.17 She’s sure that the raider is planning 15In 2013, 68% of Swiss voters backed a measure that would give shareholders of publicly traded Swiss firms a binding say on executive pay and limit managerial perquisites and potential conflicts of interest between shareholders and senior executives. 16Nathaniel Popper and Jessica Silver-Greenberg, “Citigroup Toughens Executive Bonus Rules,” New York Times, February 21, 2013. 17Unfortunately, some corporate raiders are not interested in turning the company around. Rather, they are engaged in greenmail, where they purchasing enough shares that a takeover is plausible so as to force the target firm to buy those shares back at a premium to end the takeover attempt. 7.3 Owners’ Versus Managers’ Objectives 213 a hostile takeover and will replace the current managers with new managers, whom he believes can turn around the underperforming firm. How does Sophia keep her job? If she’s like a lot of managers and corporate directors who find themselves in this position, she’ll hire the cleverest corporate lawyer she can find to construct takeover defenses. Common defenses in the United States include a shareholder rights plan, which is better known as a poison pill.18 (See Table 7.1 for a list of takeover defense terminology.) A poison pill is a provision that a corporate board adds to its bylaws or charter that makes the firm a less attractive takeover target. The law on the use of poison pills is evolving, with many countries restricting their use, including the United Kingdom and many other European countries. In Canada, regulatory authorities can remove provisions deemed to be poison pills from takeover bids, and they frequently do. Poison pills do not always work in preventing a takeover, but they frequently result in some of the resulting profit going to the original managers or boards of directors to induce them not to further fight the takeover. The use of poison pills in T A BLE 7 .1 Some Takeover Defense Terms back-end plan: Provision that gives shareholders the right to cash or debt securities at an above-market price previously defined by the company’s board in the event of a hostile takeover. dead-hand: Provision that allows only the directors who introduce the poison pill to remove it for a fixed period after they have been replaced, thereby delaying a new board’s ability to sell the firm. flip-in: Provision that gives current shareholders of the firm other than the hostile acquirer the right to purchase additional shares of stocks at a discount price after the acquirer obtains a certain percentage of the firm’s shares (usually between 20% and 50%). flip-over: Provision that allows stockholders to buy the acquiring firm’s shares at a discount price after a merger or takeover. golden handcuffs: Employment clauses that require top employees to give back lucrative bonuses or incentives if they leave the firm within a specified period of time. As a poison pill, these clauses cease to hold after a hostile takeover so that the employees may quit immediately after cashing their stock options. macaroni defense (similar to a flip-over): The issuance of many bonds with the condition they must be redeemed at an above-market price if the company is taken over. poison pill, porcupine provision, shareholder rights plan, or shark repellent: Defensive provisions that corporate boards include in the firm’s corporate charter or bylaws that make a takeover less profitable. poison puts: The issuance of bonds that investors may cash before they mature in the event of a hostile takeover attempt. 18The use of such a defense was introduced by Martin Lipton, a mergers and acquisitions lawyer, during a takeover battle where T. Boone Pickens was trying to acquire General American Oil in 1982. See activistinvesting.blogspot.com/2011/01/historial-and-legal-background-of.html (viewed February 23, 2013). 214 CHAPTER 7 Firm Organization and Market Structure the United States has declined during the last decade: More than 2,200 corporations had poison pills in 2001 compared to fewer than 900 corporations in early 2011 (Bab and Neenan, 2011). In part, this decline is due to companies increasingly allowing shareholders to vote on poison pills. Mini-Case The Yahoo! Poison Pill 7.4 The Yahoo! case illustrates that a successful poison pill defense can seriously hurt shareholders by keeping existing management. Founded in 1994 by Jerry Yang and David Filo, who were then students at Stanford, Yahoo! was a pioneer in providing information services over the Internet. As early as 2001, Yahoo! installed a poison pill. In 2008, Microsoft made an unsolicited takeover bid for Yahoo!, hoping to strengthen its Internet capabilities in its head-to-head battle with Google. In an afternoon phone call just before it made its bid, Microsoft’s chief executive, Steven Ballmer, informed a startled Jerry Yang, the chief executive of Yahoo!, that Microsoft would be making an unfriendly offer. The offer was for $31 (later raised to $33) a share, which was 60% more than the value of Yahoo! shares. According to a subsequent shareholders’ suit against Yahoo!, Mr. Ballmer made it clear that he wanted to keep Yahoo! employees and was allocating $1.5 billion for employee retention. However, Mr. Yang’s poison pill would create a “huge incentive for a massive employee walkout in the aftermath of a change in control.” The plan gave the 14,000 full-time Yahoo! employees the right to quit their jobs and “pocket generous termination benefits at any time during the two years following a takeover. . . .” Mr. Ballmer walked away from a Yahoo! deal. One Microsoft executive commented, “They are going to burn the furniture if we go hostile. They are going to destroy the place.” Yahoo!’s stock price plunged after Microsoft withdrew the bid. Soon thereafter, Yahoo! faced shareholder lawsuits and an aborted proxy fight led by Carl Icahn. Near the end of 2008, Yahoo!’s value fell as low as $10.9 billion, which was 23% of the $47.5 billion offered by Microsoft. Under pressure from stockholders, Mr. Yang resigned as CEO at the end of 2008. A sequence of new Yahoo! CEOs failed to restore Yahoo! to its former profitability. From 2009 through early 2013, its stock value ranged between $11.6 billion and $24.1 billion. That is, Microsoft could have bought Yahoo! for between 25% and 50% of what it had offered in 2008. Thus, in the end, the poison pill defense led to a Pyrrhic victory. The Make or Buy Decision Managers make many decisions that affect the horizontal and vertical dimensions of a firm’s organization. The horizontal dimension refers to the size of the firm in its primary market, while the vertical dimension refers to the various stages of the production process in which the firm participates. To produce a good and sell it to consumers involves many sequential stages of production, marketing, and distribution activities. A manager must decide how many stages the firm will undertake itself. At each stage, a manager chooses whether to carry out the activity within the firm or to pay for it to be done by others. Deciding 7.4 The Make or Buy Decision 215 which stages of the production process to handle internally and which to buy from others is part of what is referred to as supply chain management. Stages of Production The turkey sandwich you purchase at your local food stand is produced and delivered through the actions of many firms and individuals. Farmers grow wheat and raise turkeys using inputs they purchase from other firms; processors convert these raw inputs into bread and turkey slices; wholesalers transfer these products from the food processors to the food stand; and, finally, employees at the food stand combine various ingredients to make a sandwich, wrap it, and sell it to you. Figure 7.4 illustrates the sequential or vertical stages of a relatively simple production process. At the top of the figure, firms use raw inputs (such as wheat) to produce semiprocessed materials (such as flour). Then the same or other firms use the semiprocessed materials and labor to produce the final good (such as bread). In the last stage, the final consumers buy the product. In the nineteenth century, production often took place along a river. Early stages of production occurred upstream, and then the partially finished goods were shipped by barge downstream—going with the flow of the river—to other firms that finished the product. These anachronistic river terms are still used to indicate the order of production: Upstream refers to earlier stages of production and downstream refers to later stages. Vertical Integration The number of separate firms involved in producing your turkey sandwich depends on how many steps of the process each firm handles. One possibility is that the food stand carries out many steps itself: making the sandwich, wrapping it, and selling it to you. An alternative is that one firm makes and wraps the sandwich and delivers it to another firm that sells it to you. F IG U RE 7. 4 Vertical Organization Raw inputs produced upstream are combined using a production process, q = f(M, L), downstream to produce a final good. Inputs Materials M Final good q = f (M, L) Consumers q Labor L Upstream Downstream 216 CHAPTER 7 Firm Organization and Market Structure A firm that participates in more than one successive stage of the production or distribution of goods or services is vertically integrated. A firm may vertically integrate backward and produce its own inputs. For example, after years of buying its unique auto bodies from Fisher Body, General Motors purchased Fisher in a vertical merger. Or a firm may vertically integrate forward and buy its former customer. At different times, the car manufacturers General Motors and Ford have owned Hertz, the first car-rental company.19 The alternative to a firm producing an input or activity itself is to buy it. Firms may buy inputs from a market (such as buying corn on the Chicago Board of Trade or copper in the London Metal Exchange). Increasingly, many firms reach agreements with other firms to buy services from them on a continuing basis, a practice called outsourcing. For example, many U.S. computer manufacturing firms retain firms located in the United States, India, and elsewhere to provide services such as giving technical advice to their customers. A firm can be partially vertically integrated. It may produce a good but rely on others to market it. Or it may produce some inputs itself and buy others from the market. Some firms buy from a small number of suppliers or sell through a small number of distributors. These firms often control the actions of the firms with whom they deal by writing contracts that restrict the actions of those other firms. These contractual vertical restraints approximate the outcome from vertically merging. Such tight relationships between firms are referred to as quasi-vertical integration. For example, a franchisor and a franchisee have a close relationship that is governed by a contract. Some franchisors such as McDonald’s sell a proven method of doing business to individual franchisees, who are owners of McDonald’s outlets. A fast-food franchisor may dictate the types of raw products its franchisees buy, the franchisees’ cooking methods, the restaurants’ appearance, and the franchisees’ advertising. Similarly, a manufacturer that contracts with a distributor to sell its product may place vertical restrictions on the distributor’s actions beyond requiring it to pay the wholesale price for the product. These vertical restrictions are determined through contractual negotiations between the manufacturer and the distributor. The manufacturer imposes these restrictions to approximate the outcome that would occur if the firms vertically integrated. Examples of restrictions include requirements that the distributor sell a minimum number of units, that distributors not locate near each other, that distributors not sell competing products, and that distributors charge no lower than a particular price. All firms are vertically integrated to some degree, but they differ substantially as to how many successive stages of production they perform internally. At one extreme, we have firms that perform only one major task and rely on markets and outsourcing for all others. For example, some retailers, such as computer retailers, buy products from a variety of manufacturers or markets, sell them to final consumers, and have any related service such as technical support for customers provided by other firms through outsourcing arrangements. 19Hertz, founded in 1918, was purchased by General Motors in 1926, which subsequently sold it. In 1954, Hertz went public. It was sold to a Ford Motor subsidiary in 1987 and became a fully owned Ford subsidiary in 1994. Hertz went public again in 2006. 7.4 The Make or Buy Decision 217 At the other extreme, we have firms that perform most stages of the production process. The leading broiler chicken producers, such as Tyson, Purdue, and Foster Farms, have integrated or quasi-vertically integrated (through the use of contracts) into virtually every production stage except the final stage of distribution to consumers. The vertically integrated firms provide supplies to breeder farms that produce eggs. The breeder farms send eggs to a hatchery and the hatched chicks are sent to grow-out farms, where the birds grow to market weight. From there, the chickens are sent to the processing plant to be slaughtered and packed (either frozen or chilled). Packed chicken is then shipped to another company-owned plant for further processing into products such as frozen nuggets and chicken dinners. Finally, the products are sold to other firms such as fast-food restaurants and grocery stores for sale to final consumers (Martinez, 1999). By vertically integrating, these firms are able to take advantage of very large economies of scale at virtually every stage of the production process. However, no firm is completely integrated: It would have to run the entire economy. Even Foster Farms buys some inputs, such as its equipment, from outside markets. As Carl Sagan observed, “If you want to make an apple pie from scratch, you must first create the universe.” Profitability and the Supply Chain Decision Firms decide whether to vertically integrate, quasi-vertically integrate, or buy goods and services from markets or other firms depending on which approach is the most profitable.20 Although at first glance this profitability rule seems very simple, it has a number of tricky aspects. First, the firm has to take into account all relevant costs, including some that are not easy to quantify such as transaction costs. Second, the firm must ensure a steady and timely supply of needed inputs to its production process. Third, the firm may vertically integrate, even if doing so raises its cost of doing business, so as to avoid government regulations.21 As a consequence of these complexities, firms in the same industry may reach different decisions about the optimal level of integration. We observe that such firms handle the supply chain in different ways. In the auto industry, Toyota is known as a leader in successful outsourcing and is less vertically integrated than its rivals such as General Motors and Ford. Firms in some markets differ in how much they integrate because their managers have different strengths or the firms face different costs (such as costs that vary across countries). However, some of these firms could be making a mistake by being more or less integrated than other firms, which will lower their profits and possibly drive them out of business. 20For a more detailed analysis of the pros and cons of vertical integration, see Perry (1989) and Carlton and Perloff (2005). Two classic articles on vertical integration are Coase (1937) and Williamson (1975). 21Firms may also vertically integrate for reasons related to market power, allowing the firm to charge higher prices than it otherwise would or to reduce prices it would otherwise pay for its inputs. We discuss market power issues in later chapters. 218 CHAPTER 7 Firm Organization and Market Structure M ini-Case Vertical Integration at American Apparel The high-fashion garment industry in the United States is noted for outsourcing and for a complex and highly decentralized supply chain. Major clothing brands typically outsource sewing and various other specialized manufacturing functions to subcontractors in a variety of low-wage countries. Bucking this trend is American Apparel, a fast-growing Los Angeles garment maker. As noted by Warren (2005), “American Apparel’s greatest . . . innovation may come in the form of its vertical integration, in which every aspect of the business . . . occurs in some portion of the million square feet of American Apparel’s Los Angeles space.” Founder and CEO Dov Charney, originally from Montreal, argues that “controlling all the variables in-house leads to greater efficiency, better wages and more flexibility. . . .” Charney takes vertical integration to an extreme. In 2013 the firm’s website claimed that “By concentrating our entire manufacturing and distribution operations within a few square miles, American Apparel . . . saves time, money, and unnecessary fuel expenditures.” Not only does American Apparel design its clothing and handle its own sewing, it also has its own knitting facility and dyeing operation to produce much of the cloth it uses and it carries out the wholesaling and retailing functions. American Apparel also does its own marketing and advertising. Most of the models used in its provocative advertisements are ordinary employees and many of the photos used in advertising campaigns are taken by CEO Charney. Indeed, its advertising cites its extreme vertical integration as a selling point. American Apparel even runs its own medical clinic onsite in Los Angeles. This extremely high level of vertical integration saves on transportation costs, allows for close cooperation between designers, production managers and marketers and, supporters argue, leads to a loyal, dedicated, and knowledgeable workforce. However, it may raise their costs of producing clothing. Time will tell if American Apparel’s alternative approach is sound. Transaction Costs. Probably the most important reason to integrate is to reduce transaction costs, especially the costs of writing and enforcing contracts. A firm that vertically integrates avoids many transaction costs, but its managerial costs rise as the firm becomes larger and more complex. For example, a manufacturing firm may decide to vertically integrate forward (downstream) into distributing its own products or it may rely on independent firms to distribute its products. The decision depends on whether the cost of monitoring employees at distribution outlets exceeds the cost of using independent firms. However, even if the independent firms can perform the service at a lower cost per unit, the manufacturer may choose to vertically integrate if the expense from trying to prevent opportunistic behavior by these firms is high. The manufacturer cannot perfectly observe the sales effort of the distributors and realizes that they may try to take advantage. That is, when firms agree to a future transaction, each firm may try to interpret the terms of a contract to its advantage, especially when terms are vague or missing. Opportunistic behavior is particularly likely when a firm deals with only one other firm: a classic principal-agent problem. If an electronic game manufacturer can buy computer chips from only one firm, it is at the mercy of that chip supplier. The supplier could take advantage of the situation by increasing its price substantially 7.4 The Make or Buy Decision 219 just before the holiday buying season. The game manufacturer may vertically integrate—manufacturing the chip itself—to avoid such opportunistic behavior. Another potential source of transaction costs is a need for coordination. American Apparel felt that the costs of coordinating various aspects of clothing production are high enough to justify vertical integration. Security and Flexibility of Supply. A common reason for vertical integration is to ensure supply of important inputs. Having inputs available on a timely basis is very important in many if not most industries. Costs would skyrocket if a car manufacturer had to stop assembling cars while waiting for a part. Backward (upstream) integration to produce the part itself may help to ensure timely arrival of parts. Alternatively, this problem may be eliminated through quasi-vertical integration, in which the buyer and seller agree to a contract whereby the supplier is rewarded for prompt delivery and penalized for delays. Toyota and other Japanese manufacturers pioneered the just-in-time system of having suppliers deliver inputs at the time needed to process them, thus minimizing inventory costs and avoiding bottlenecks. Similarly, it is often important that a firm be able to vary its production quickly. If the demand curve shifts to the left during a recession, a firm may want to cut output, and hence temporarily reduce its use of essential inputs. By vertically integrating, firms may gain greater flexibility. PepsiCo Inc. offered to buy its two largest bottlers, Pepsi Bottling Group and PepsiAmericas, because, as PepsiCo Chairwoman and Chief Executive Officer Indra Nooyi said, “We could unlock significant cost synergies, improve the speed of decision making and increase our strategic flexibility.”22 Mini-Case Aluminum Backward vertical integration is common in the aluminum industry to ensure a steady supply and to avoid being subject to opportunistic behavior. Aluminum production has four main stages: mining, refining, smelting, and fabricating. After mining bauxite, a firm mixes it with caustic soda to refine it into alumina. In the smelting stage, the firm uses electrolysis to produce primary aluminum metal from alumina. Finally, that firm or other firms fabricate the metal into foil, wire, cookware, airplane parts, and many other products. A few firms engage in the upstream activities of mining and refining bauxite. Bauxite mines and refineries require large capital investments and face substantial barriers to entry. Only 132 alumina refineries operate worldwide as of 2013, and these are owned by a much smaller number of entities. Moreover, bauxite is expensive to ship, so the market for bauxite is regional. Thus, a mine or a refiner has few if any other firms with which it can deal. To guarantee a steady supply, some refineries quasi-vertically integrate by signing 20- to 25-year contracts with mines. Because these firms cannot foresee all possible contingencies during such long periods, one trading party can inflict substantial costs on the other by refusing to deal with it (say, when prices are unusually high or low). These firms have no alternative uses for bauxite and the plants that mine and refine it. 22“PepsiCo bids to buy its bottlers,” Marketwatch, April 20, 2009, www.marketwatch.com/story/ pepsico-bids-buy-bottlers-reports. 220 CHAPTER 7 Firm Organization and Market Structure To avoid the potential for such opportunistic behavior, many of the major producers of aluminum—Alcan Aluminium Ltd. (Canada), Alcoa (Aluminum Company of America), Chalco (China), Comalco (Australia, New Zealand, and Wales), and Pechiney (France)—vertically integrated in bauxite mining, alumina refining, and aluminum smelting. Vertically integrated firms mine and refine virtually all of the world’s bauxite and alumina. Avoiding Government Intervention. Firms may also vertically integrate to avoid government price controls, taxes, and regulations. A vertically integrated firm avoids price controls by selling to itself. For example, the U.S. government has set a maximum price for steel products on several occasions since World War II. Under such price controls, steel producers did not want to sell as much steel as before the controls took effect. Consequently, they rationed steel, selling their long-time customers only a fraction of what they sold before the controls went into effect. Because transactions within a company were unaffected by price controls, a buyer who really desired more steel could purchase a steel company and obtain all the steel it wanted (and at least one firm did so). Thus, purchasing a steel company allowed firms to avoid price controls. Were it not for the high transaction costs, firms could completely avoid price controls by vertically integrating. More commonly, firms integrate to lower their taxes. Tax rates vary by country, state, and type of product. A vertically integrated firm can shift profit from one of its operations to another simply by changing the transfer price at which it sells its internally produced materials from one division to another. By shifting profits from a high-tax state or country to a low-tax state or country, a firm can increase its after-tax profits. The Internal Revenue Service tries to restrict such behavior by requiring that firms use market prices for internal transfers where possible. Government regulations create additional incentives for a firm to integrate vertically (or horizontally) when the profits of only one division of a firm are regulated. When the government restricts the profit that a local telephone company earns on local services but not its profit on other services, such as selling telephones in competition with other suppliers, the telephone company tries to shift profits from its regulated division to its unregulated division. 7.4 The Make or Buy Decision 221 Market Size and the Life Cycle of a Firm Why do workers commonly engage in highly specialized activities? The answer is that it is generally more efficient to divide production processes into several small steps in which workers specialize, with each worker becoming skilled in a certain activity. Adam Smith, writing in Scotland at the time of the American Revolution, gave an example of a pin factory in The Wealth of Nations to illustrate that the division of labor can have important advantages in the “very trifling manufacture” of pins: [A] workman not educated to this business . . . nor acquainted with the use of machinery employed in it . . . could scarce, perhaps, with his utmost industry, make one pin a day, and certainly could not make twenty. But in the way in which this business is now carried on, not only the whole work is a peculiar trade, but it is divided into a number of branches, of which the greater part are likewise peculiar trades. One man draws out the wire, another straightens it, a third cuts it, a fourth points it, a fifth grinds it to the top for receiving the head; to make the head requires two or three distinct operations; to put it on, is a peculiar business, to whiten the pins is another; it is even a trade by itself to put them into the paper; and the important business of making a pin is, in this manner, divided into about eighteen distinct operations, which, in some manufactories, are all performed by distinct hands, though in others the same man will sometimes perform two or three of them. I have seen a small manufactory of this kind where ten men only were employed, and where some of them consequently performed two or three distinct operations. . . . [T]hey could, when they exerted themselves, make among them about twelve pounds of pins in a day [or] upward of forty-eight thousand pins in a day. Using this insight about specialization, Henry Ford became the largest and probably the most profitable automobile manufacturer in the early 1900s by developing mass production techniques. He adapted the conveyor belt and assembly line so that he could produce a standardized, inexpensive car in a series of tasks in which individual workers specialized. By doing so, he achieved cost savings despite paying wages that were considerably above average. Despite the advantages of specialization, many workers and many firms do not specialize. Why? According to Adam Smith, the answer is that “the division of labor is limited by the extent of the market.” That is, a firm can take advantage of specialization and economies of scale only if it produces a sufficiently large amount of output, which it produces only if enough consumers are willing to buy it. Stigler (1951) and Williamson (1975) showed that Adam Smith’s insight provides a theory of the life cycle of firms. They explain why firms rely on markets during certain periods, while during other periods, they vertically integrate. The key insight is that the degree of integration depends on the size of the market. If demand for a product at the current price is low so that the collective output of all the firms in the industry is small, each firm must undertake all the activities associated with producing the final output itself. Why don’t some firms specialize in making one of several inputs that they then sell to another firm to assemble the final product? The answer is that when the industry is small, it does not pay for a firm to specialize in one activity even given increasing returns to scale. A specialized firm may have a large setup or fixed cost. If the specialized firm produces large quantities of output, the average fixed cost per unit is small. In contrast, the average fixed cost is large in a small industry. Therefore, if specialized firms are to earn a profit, the sum of the 222 CHAPTER 7 Firm Organization and Market Structure specialized firms’ prices must be higher than the cost of a firm that produces everything for itself. As the industry expands, it may become profitable for a firm to specialize, because the per-unit transaction costs fall. That is, as the industry grows, firms vertically disintegrate. When the industry was small, each firm produced all successive steps of the production process, so that all firms were vertically integrated. In the larger industry, each firm does not handle every stage of production itself but rather buys services or products from specialized firms. As an industry matures further, new products often develop and reduce much of the demand for the original product, so that the industry shrinks in size. As a result, firms again vertically integrate. 7.5 Market Structure When making their horizontal and vertical decisions, managers need to take account of the behavior of actual and potential rival firms, which affect the profit function the manager’s firm faces. So far, we have implicitly ignored the role of other firms. However, a firm’s manager must take into account how its profit is affected by rival firms’ output levels, the prices rivals set, or whether additional firms are likely to enter the market if the firm makes a large profit. How rivals behave depends on the organization of the industry in which the firms operate. A firm will behave differently if it is one of a very large number of firms rather than the only firm in the market. The behavior of firms depends on the market structure: the number of firms in the market, the ease with which firms can enter and leave the market, and the ability of firms to differentiate their products from those of their rivals. The Four Main Market Structures Most industries fit into one of four common market structures: perfect competition, monopoly, oligopoly, and monopolistic competition. Perfect Competition. When most people talk about competitive firms, they mean firms that are rivals for the same customers. By this interpretation, any market that has more than one firm is competitive. However, economists often use the term competitive to refer to markets that satisfy the conditions for perfect competition (Chapter 2) or that closely approximate perfect competition. Economists say that a market is perfectly competitive if each firm in the market is a price taker: a firm that cannot significantly affect the market price for its output or the prices at which it buys its inputs. Firms are likely to be price takers in markets where all firms in the market sell identical products, firms can freely enter and exit the market in the long run, all buyers and sellers know the prices charged by firms, and transaction costs are low. If any one of the 26,000 tomato producers in the United States were to stop producing or to double its production, the market price of tomatoes would not change appreciably. Similarly, by stopping production or doubling its production, a producer would have little or no effect on the price for fertilizer, labor, or other inputs. Because firms can enter freely, firms enter whenever they see an opportunity to make an economic profit. This entry continues until the economic profit of the last firm to enter—the marginal firm—is zero. 7.5 Market Structure 223 Monopoly. A monopoly is the only supplier of a good for which there is no close substitute. In 1937, Alcoa controlled the entire markets for bauxite, alumina, and primary aluminum. Today, the postal service in most countries and many local public utilities such as cable television companies are local monopolies. Patents give monopoly rights to sell inventions, such as particular pharmaceuticals. A firm may be a monopoly if its costs are substantially below those of other potential firms. A monopoly can set its price—it is not a price taker like a competitive firm. A monopoly’s output is the market output, and the demand curve a monopoly faces is the market demand curve. Because the market demand curve is downward sloping, the monopoly—unlike a competitive firm—doesn’t lose all its sales if it raises its price. As a consequence, the monopoly typically charges relatively high prices— much higher than the price set in a perfectly competitive market. Oligopoly. An oligopoly is a market with only a few firms and with substantial barriers to entry, which prevent other firms from entering. A barrier to entry could be a government licensing law that limits the number of firms or patents that prevent other firms from using low-cost technologies. Nintendo, Microsoft, and Sony are oligopolistic firms that dominate the video game market. Only a handful of firms control the automobile, television, and aircraft manufacturing markets. Because relatively few firms compete in an oligopolistic market, each can influence the price. One reason why oligopolies are price setters is because many oligopolies differentiate their products from those of their rivals. Because consumers perceive differences between a Honda Accord and a Toyota Camry, Toyota can raise the price of its Camry above the price of an Accord without losing all its sales. Some customers who prefer the Camry to the Accord will buy a Camry even if it costs more than an Accord. Moreover, because an oligopoly has few firms, the actions of each firm affect its rivals. An oligopoly firm that ignores or inaccurately predicts its rivals’ behavior is likely to lose profit. For example, as Toyota produces more cars, the price Honda can get for its cars falls. If Honda underestimates how many cars Toyota will produce, Honda may produce too many automobiles and lose money. The need to consider the strategies of rival firms makes analyzing an oligopoly firm’s profit-maximization decision more difficult than that of a monopoly or a competitive firm. A monopoly has no rivals, and a perfectly competitive firm ignores the behavior of individual rivals—it considers only the market price and its own costs in choosing its profit-maximizing output. Oligopolistic firms may act independently or may coordinate their actions. A group of firms that explicitly agree (collude) to coordinate their activities is called a cartel. These firms may agree on how much each firm will sell or on a common price. By cooperating and behaving like a monopoly, the members of a cartel seek to collectively earn the monopoly profit—the maximum possible profit. In most developed countries, cartels are illegal. If oligopolistic firms do not collude, they earn lower profits than a monopoly, but usually earn higher profits than do firms in a competitive industry. Monopolistic Competition. Monopolistic competition is a market structure in which firms are price setters but entry is easy. As in a monopoly or oligopoly, there are few enough firms that each can affect the price. Indeed, monopolistically competitive firms often differentiate their products, which facilitates their ability to be price setters. However, as in competition, firms can freely enter, so the marginal firm earns zero economic profit. 224 CHAPTER 7 Firm Organization and Market Structure Comparison of Market Structures Table 7.2 summarizes the major features of these four market structures. The first row notes that perfectly competitive firms are price takers, whereas monopolies, oligopolies, and monopolistically competitive firms are price setters. Typically, monopolies charge higher prices than oligopolies and monopolistically competitive firms, while competitive firms charge lower prices. In both competitive and monopolistically competitive markets, entry occurs until no new firm can profitably enter, so the marginal firm earns zero economic profit. Monopolistically competitive markets typically have fewer firms than perfectly competitive markets do. Barriers to entry in a market result in a monopoly with one firm or an oligopoly with few firms. Monopolies and oligopolies may earn positive economic profits. Oligopolistic and monopolistically competitive firms must pay attention to rival firms’ behavior, in contrast to monopolistic or competitive firms. A monopoly has no rivals. A competitive firm ignores the behavior of individual rivals in choosing its output because the market price tells the firm everything it needs to know about its competitors. Oligopolistic and monopolistically competitive firms may produce differentiated products in contrast to monopolies and competitive firms. Road Map to the Rest of the Book In Chapters 8 through 13, we examine the market outcomes under perfect competition, monopoly, oligopoly, and monopolistic competition. We start by examining competitive and monopoly firms, which can ignore the behavior of other firms. Then we turn to oligopolies and other markets where firms need to develop strategies to compete with rival firms. In these chapters, we maintain the assumption that T A B L E 7 . 2 Properties of Monopoly, Oligopoly, Monopolistic Competition, and Perfect Competition Monopoly Oligopoly Monopolistic Competition Perfect Competition 1. Ability to set price Price setter Price setter Price setter Price taker 2. Price level Very high High High Low 3. Entry conditions No entry Limited entry Free entry Free entry 4. Number of firms 1 Few Few or many Many 5. Long-run profit Ú0 Ú0 0 0 6. Strategy dependent on individual rival firms’ behavior No (has no rivals) Yes Yes No (cares only about market price) 7. Products Single product May be differentiated May be differentiated Undifferentiated 8. Example Producer of patented drug Automobile manufacturers Plumbers in a small town Apple farmers 7.5 Market Structure 225 firms seek to maximize profits. In contrast, in Chapters 14 through 16 we return to the realistic issues introduced in this chapter concerning uncertainty, unequal information, and government regulation, which lead to agency problems. In Chapter 17, many of the issues raised in this chapter, such as outsourcing, are considered in a global context. M a nagerial So lution Clawing Back Bonuses Does evaluating a manager’s performance over a longer time period lead to better management? The answer depends on whether the reward a manager receives in the short run induces the manager to sacrifice long-run profit for short-run gains. Managers prefer to be paid sooner rather than later because money today is worth more than the same amount later. Thus, if a manager can move a major sale from January of next year to December of this year, the firm’s total profits over the two years are unchanged, but the manager’s performance-based bonus is paid this year rather than next year. Most boards are probably not very concerned with such shifts over time as they are unlikely to lower long-run profits. Of more concern are managers who increase this year’s profit even though doing so lowers profit in later years. Many firms pay a bonus on a positive profit but do not impose fines or penalties (negative bonuses) in bad years. Suppose that a particular policy results in a large profit this year but an even larger loss next year. If the manager gets a bonus based on each year’s profit, the manager receives a large bonus this year and no bonus next year. However, if the bonus is calculated over two years, the manager would receive no bonus in either year. A firm could achieve a similar effect by allowing for a bonus given in one year to be clawed back if the firm does badly in the subsequent year. Without such clawbacks the manager has a greater incentive to adopt this policy of increasing profit in one year at the cost of lower profit the next. In an extreme case, a manager engages in reckless behavior that increases this year’s profit but bankrupts the firm next year. The manager plans to grab this year’s bonus and then disappear. There were many such examples of bad management leading up to the 2007–2009 financial meltdown involving mortgage and financial instruments, such as CDOs, based on mortgages. As described in the Managerial Problem, bad CDO decisions at Merrill Lynch cost its shareholders billions of dollars, while senior managers kept the bonuses despite the negative effects of their decisions on shareholders. One solution to bad managerial incentives is to base bonuses on more than one year. Starting in 2012, Morgan Stanley paid bonuses to high-income employees over a three-year period. Similarly, Apple stock options and related benefits are paid every two years rather than every year. To illustrate why paying over time provides a better incentive structure, we examine the case of Angelo, who is an executive in a company that provides auto loans for a two-year period. Initially, he receives 10% of the amount of the loans he makes in the first year. He can loan to two groups of customers. Customers in one group have excellent financial histories and repay their loans on time. Loans to this group produce revenue of $10 million this year, so that over the two-year period, the firm nets $9 million after paying Angelo. Customers in the 226 CHAPTER 7 Firm Organization and Market Structure other group are much more likely to default. That group produces $30 million in revenue this year, but their defaults in the second year cost the firm $40 million. After paying Angelo $3 million in the first year, the firm suffers a $13 million loss over the two years (ignoring discounting). Because Angelo prefers receiving $4 million by loaning to both groups to $1 million from loaning to only the good risks, he may expose the firm to devastating losses in the second year. He may be happy earning a gigantic amount in the first year even if he’s fired in the second year. This management problem can be avoided if his compensation is based on profit over a two-year period, where he has less incentive to loan to the bad risks. S U MMARY 1. Ownership and Governance of Firms. For-profit firms are normally organized as sole proprietorships, partnerships, or corporations. Owners may manage small companies (particularly sole proprietorships and partnerships) themselves, but owners of larger firms (particularly corporations) typically hire managers to run such firms. Government-owned firms and nonprofit firms normally have objectives other than profit maximization. 2. Profit Maximization. Most firms maximize economic profit, which is revenue minus economic cost (opportunity cost). A firm earning zero economic profit is making as much as it could if its resources were devoted to their best alternative uses. To maximize profit, a firm must make two decisions. First, the firm determines the quantity at which its profit is highest. Profit is maximized when marginal profit is zero or, equivalently, when marginal revenue equals marginal cost. Second, the firm decides whether to produce at all. It shuts down if doing so reduces a loss (negative profit) it would otherwise suffer. 3. Owners’ Versus Managers’ Objectives. Owners and managers may have conflicting objectives. For example, an owner may want to maximize the firm’s profit, while the manager is interested in maximizing personal earnings. Such conflicts are an example of a principle-agent problem or agency problem, where the principal (owner) hires an agent (manager) to perform an action, and the agent acts in his or her own best interest. The owner can use a variety of means including monitoring, contingent rewards, and corporation rules to influence or control the manager’s behavior. Market pressures also make it difficult for a firm to deviate substantially from profit-maximizing behavior. 4. The Make or Buy Decision. A firm may engage in many sequential stages of production itself, perform only a few stages itself and rely on markets for others, or use contracts or other means to coordinate its activities with those of other firms, depending on which approach is most profitable. A firm may vertically integrate (participate in more than one successive stage of the production or distribution of goods or services), quasi-vertically integrate (use contracts or other means to control firms with which it has vertical relations), or buy from others depending on which is more profitable. Key incentives to vertically integrate include lowering transaction costs, ensuring a steady supply, and avoiding government restrictions. 5. Market Structure. A firm’s profit depends in large part on the market structure, which reflects the number of firms in the market, the ease with which firms can enter and leave the market, and the ability of firms to differentiate their products from those of their rivals. The major market structures are perfect competition, monopoly, oligopoly, and monopolistic competition. Competitive firms are price takers, whereas others are price setters. Oligopolies and monopolistically competitive firms, unlike competitive firms and monopolies, must take account of rivals’ strategies and may differentiate their products. Competitive and monopolistically competitive firms are in markets where entry by potential rivals is easy, so economic profit is driven to zero. Questions 227 Q U E S T ION S All exercises are available on MyEconLab; * = answer at the back of this book; C = use of calculus may be necessary. 1. Ownership and Governance of Firms 1.1. What types of firms would not normally maximize profit? *1.2. Describe three important consequences of “going public” by selling shares in an initial public offering. 1.3. What types of firm organization allow owners of a firm to obtain the advantages of limited liability? 2. Profit Maximization 2.1. A firm has three different production facilities, all of which produce the same product. While reviewing the firm’s cost data, Jasmin, a manager, discovers that one of the plants has a higher average cost than the other plants and suggests closing that plant. Another manager, Joshua, notes that the high-cost plant has high fixed costs but that the marginal cost in that plant is lower than in the other plants. He says that the high-cost plant should not be shut down but should expand its operations. Who is right? *2.2. A firm has revenue given by R(q) = 100q - 3q2 and its cost function is C(q) = 100 + 10q. What is the profit-maximizing level of output? What profit does the firm earn at this output level? (Hint: See Q&A 7.1.) C 2.3. Should a firm ever produce if it is losing money (making a negative economic profit)? Why or why not? *2.4. Should a firm shut down if its weekly revenue is $1,000, its variable cost is $500, and its fixed cost is $800, of which $600 is avoidable if it shuts down? Why? 2.5. A firm has to pay a tax equal to 25% of its revenue. Give a condition that determines the output level at which it maximizes its after-tax profit. (Hint: See “Using Calculus: Maximizing Profit” and Q&A 7.1.) C 2.6. At the time of its initial public offering (initial sale of stock), Groupon, an Internet company that provides discount coupons, used unusual measures of its business performance (Michael J. de la Merced, “Abracadabra! Magic Trumps Math at Web Start-Ups,” dealbook.nytimes.com, June 17, 2011). One such measure used by Groupon was acsoi (pronounced “ack-soy” or, alternatively, “ack-swa”) for “adjusted consolidated segment operating income.” Acsoi is operating profit before subtracting the year’s online marketing and acquisition expenses. The firm’s profit was negative, but its acsoi was positive. Groupon argued that acsoi marketing and acquisition expenses were an investment that would build future business and whose costs should therefore be amortized (spread out over time). If shareholders care about the stock price or the present value of the company, is acsoi an appropriate measure? 2.7. A firm that owns and manages rental properties is considering buying a building that would cost $800,000 this year, but would yield an annual revenue stream of $50,000 per year for the foreseeable future. For what range of interest rates would this purchase increase the present value of the firm? 3. Owners’ Versus Managers’ Objectives 3.1. In Q&A 7.2, suppose that Ann’s compensation, Y, is half of the firm’s profit minus $30,000: Y = π/2 - 30,000. Will she still seek to maximize the firm’s profit? 3.2. A firm’s revenue varies with its output: R(q). Its manager’s income, Y, equals aR(q), where 0 6 a 6 1 is the manager’s share of the firm’s revenue. Use calculus to prove that maximizing aR(q) implies the same output level, q, as maximizing R(q). What does this result imply about the manager’s incentive to maximize the firm’s profit, π(q) = R(q) - C(q)? Would it be better for shareholders if the manager received a share of profit rather than a share of revenue? (Hint: See Q&A 7.2 and Q&A 7.3.) C 3.3. Three firms have identical revenue and profit functions with the same general shape as those in Figure 7.3. Firm 1 is a private sector firm operated by an owner-manager who wishes to maximize profit. Firm 2 is managed by an income-maximizing manager whose pay is proportional to the firm’s revenue. Firm 3 is a government-owned firm that has been instructed to maximize the amount of employment, L, subject to the constraint that revenue must not be negative. To increase q, L must increase. Which of these firms produces the most, which the least, and which is in the middle? Show the output level of each firm in a diagram. *3.4. Each of the three firms in Question 3.3 has a revenue function R(q) = 100q - 2q2 and a cost function C(q) = 100 + 20q. Determine how much output each firm chooses. C 3.5. Michael, the CEO of a successful firm, enjoys both income, Y, and perquisites, S (such as a nice office and expensive office furniture). Michael’s utility function (Chapter 4) is U(S, Y) with normal (convex to the origin) indifference curves. Michael 228 CHAPTER 7 Firm Organization and Market Structure receives a base salary of M. He is able to determine the level of perquisites provided by the firm up to a maximum allowable budget of B. However, any of this budget not spent on perquisites is given to Michael as a bonus over and above his base salary. Illustrate Michael’s utility maximization problem in a diagram in which you show his indifference curves and his budget line. 3.6. Inside directors of a firm are also executives of the firm, and they normally receive compensation that includes some form of profit sharing. Outside directors are not employees of the firm. They normally receive some compensation but do not have profitsharing arrangements. Outside directors are often charged with determining salaries of senior executives. From the shareholders’ point of view, why would it be desirable for outside directors to have this responsibility? 3.7. Why are steps taken by corporate management to avoid takeovers often not in shareholders’ best interests? 3.8. How does the market for corporate control encourage firms to maximize profits? 3.9. An acquiring firm, A, seeks to buy a target firm, T. The acquiring firm has better managers. The value of the target firm, if acquired by A, is $100 million. The value of the target firm under its current management is only $80 million. However, the managers of T can impose a poison pill that would reduce the value of firm T to the acquirer by amount P without providing any benefit to shareholders of T. What is the minimum value of P that would prevent A from acquiring T? What is the cost of this poison pill to shareholders of the two firms? 4. The Make or Buy Decision * 4.1. In 2012, the Campbell Soup Company acquired Bolthouse Farms for $1.55 billion. This acquisition increased the level of vertical integration in Campbell, as Bolthouse Farms owned and operated extensive farming operations where it produced many food items used in Campbell’s products. Suppose that the value of produce provided by these farms after the acquisition would be $75 million per year for Campbell and that, in addition, Campbell could save $10 million per year in costs it would otherwise spend in searching for and negotiating over equivalent produce. However, the transaction cost of the acquisition (lawyers’ fees, relocating some production facilities, paying severance to unnecessary employees, etc.) required a one-time payment of $50 million. If the interest rate used to discount future earnings is 5%, what is the gain to Campbell’s from the acquisition? 4.2. Katie’s Quilts is a small retailer of quilts and other bed linen products. Katie currently purchases quilts from a large producer for $100 each and sells them in her store at a price that does not change with the number of quilts that she sells. Katie is considering vertically integrating by making her own quilts. If the fixed cost of vertically integrating is $10,000 and she can produce quilts at $50 per quilt, her total cost of producing quilts, q, herself is C = 10,000 + 50q. How many quilts does Katie need to sell for vertical integration to be a profitable decision? 4.3. A producer of ballpoint pens has been purchasing ink from an ink supplier and is considering acquiring the ink supplier. Would the pen company be more or less likely to vertically integrate by buying the ink manufacturer if the government taxes ink? 4.4. When the western part of the United States was sparsely populated, many small towns had a single schoolhouse in which one teacher taught all subjects to students of all ages. Nowadays, in large cities, teachers are often highly specialized, teaching a single subject, such as mathematics, to just one grade level. Explain why this change occurred by making reference to Adam Smith’s famous description of a pin factory. 5. Market Structure 5.1. Which market structure best describes (a) airplane manufacturing, (b) electricians in a small town, (c) farms that grow tomatoes, and (d) cable television in a city? Why? 6. Managerial Problem 6.1. Consider the following change to Angelo’s situation in the Managerial Solution. Now Angelo can provide loans to only one of the two groups. If he loans to the safer group, he gets his 10% in Year 1 and faces the same choice in Year 2 with two new groups of borrowers. If he loans to the risker group, he gets 10% but will be fired in the second year and earns nothing when the risky loans start to go bad. If Angelo wants to maximize his earnings over the two years (ignoring discounting), what will he do in each year? Would his firm gain by using a system of deferred compensation? Questions 7. Spreadsheet Exercises 7.1. A firm’s revenue function is R(q) = 90q - 2q . Its cost function is C(q) = 104 + 6q + 1.5q2. 2 a. Using Excel, calculate the levels of revenue, total cost, and profit for the firm for q = 0, 1, 2, c, 24. Determine the profit-maximizing output and the maximum profit for the firm. b. Using Excel’s Charting tool, draw the graph of the profit curve and determine the profit-maximizing level of output. c. The firm’s marginal revenue function is MR = 90 - 4q and the marginal cost function is MC = 6 + 3q. Using Excel, calculate MR and MC for q = 0, 1, 2, c , 24. Verify that the “MR = MC” rule determines the same profitmaximizing output as you found in part (a). 7.2. A firm has the same revenue and cost function as in Spreadsheet Exercise 7.1. a. The shareholders of the firm hire a manager on a profit-sharing basis whose payment, M, 229 is 25% of the firm’s profit: M = 0.25(R - C). The shareholders receive the remaining 75%, so their income is S = 0.75(R - C). Add columns for M and S to the spreadsheet in part a of Exercise 7.1 and calculate the manager’s payment and the shareholders’ income for q = 0, 1, 2, c , 20. Determine the amount of output that the manager will produce if the manager’s objective is to maximize his or her own compensation. Is this outcome consistent with the shareholders’ profit-maximizing objective? b. Now suppose that the manager receives compensation equal to 10% of revenue, so that the return to the owners is S = 0.9R - C. Use Excel to determine the return to the manager and the return to the owners for q = 0, 1, 2, c , 20. Are the incentives of the shareholders and the manager aligned in this case? Appendix 7 Interest Rates, Present Value, and Future Value To make decisions based on cash flows such as costs and revenues over time, managers compare current and future cash flows using interest rates. The interest rate, i, connects the value of money you invest today, the present value, PV, and the amount that you will be repaid later, the future value, FV. For example, if you put $100 in the bank today, your present value is $100. If the annual interest rate is i = 5% = 0.05, then a year from now the bank will return your original $100 and give you an additional interest payment of $5 = 0.05 * 100, so that your future value is $105 one year from now. More generally, if you invest PV today at an interest rate of i, one year from now you will receive FV = PV(1 + i). If you leave this future value, PV(1 + i) in the bank for a second year to earn more interest, you’ll receive PV(1 + i)(1 + i) = PV(1 + i)2 at the end of the second year. That is, in the second year, you are earning interest on both your original investment and the interest payment from the first year. After t years, the future value is FV = PV(1 + i)t. (7A.1) t Dividing both sides of Equation 7A.1 by (1 + i) , we can express the present value in terms of the future value: PV = FV . (1 + i)t (7A.2) For example, if the interest rate is 5% and you will receive a payment of $105 with certainty one year from now, your present value of this future payment is PV = 105/(1.05) = 100. Because the future payment of $105 has a present value of only $100, we say that the future payment is discounted when compared with the present. At high interest rates, money in the future is virtually worthless today. Using Equation 7A.2, we can calculate that a $100 payment 25 years from now is worth only slightly more than $1 today at a 20% interest rate: PV = 100/(1.2)25 ≈ 100/95.4 ≈ $1.05. Sometimes we want to calculate the present value of a stream of payments, such as the firm’s annual profits over the next 15 years. We can generalize the relationships we have already developed to determine the present value of the stream of payments by calculating the present value of each future payment and then summing them. Suppose an investor has a share that pays $10 in dividends at the end of each year for three years and nothing thereafter. If the interest rate is 10%, the present value of this series of payments is PV = 230 $10 $10 $10 + + ≈ $24.87. 1.1 1.12 1.13 Appendix 7 Interest Rates, Present Value, and Future Value 231 More generally, a stream of payments of f per year for t years given interest rate i has a present value of PV = f J 1 1 1 + + g + R. (1 + i)t (1 + i)2 (1 + i)1 (7A.3) If these dividend payments are made at the end of each year forever, Equation 7A.3 can be simplified. If you invest PV at i forever, you can receive a future payment of f = PV * i each year forever. Dividing both sides of this equation by i, we find that f PV = . i (7A.4) 8 Competitive Firms and Markets The love of money is the root of all virtue. —George Bernard Shaw Ma nagerial P ro blem The Rising Cost of Keeping On Truckin’ To plan properly, managers need to be able to predict the impact of new government regulations on their firms’ costs, their sales, and their probability of surviving. Managers complain constantly about the costs and red tape that government regulations impose on them. The very competitive U.S. trucking industry has a particular beef. In recent years, federal and state fees have increased substantially and truckers have had to adhere to many new regulations. The Federal Motor Carrier Safety Administration (FMCSA) along with state transportation agencies in 41 states (as of 2013) administer interstate trucking licenses through the Unified Carrier Registration Agreement. Before going into the interstate trucking business, a firm needs a U.S. Department of Transportation number and must participate in the New Entrant Safety Assurance Process, which raised the standard of compliance for passing the new entrant safety audit starting in 2009. To pass the new entrant safety audit, a carrier must now meet 16 safety regulations and be in compliance with the Americans with Disabilities Act and certain household goods-related requirements. A trucker must also maintain minimum insurance coverage, pay registration fees, and follow policies that differ across states before the FMCSA will issue the actual authorities (grant permission to operate). The registration process is so complex and timeconsuming that firms pay substantial amounts to brokers who expedite the application process and take care of state licensing requirements. According to its website in 2013, the FMCSA has 27 types of driver regulations, 16 types of vehicle regulations, 42 types of company regulations, 4 types of hazardous materials regulations, and 14 types of other regulatory guidance. Of course, they may have added some additional rules while we wrote this last sentence.1 For a large truck, the annual federal interstate registration fee can exceed $8,000. During the 2007–2009 financial crisis, many states raised their annual fee from a few hundred to several thousand dollars per truck. In 2012, Congress debated requiring that each truck install an electronic onboard recorder, which would document its travel time and distance and cost $1,500. There are many additional fees and costly regulations that a trucker or firm must meet to operate. These largely lump-sum costs—which are not related to the number of miles driven—have increased substantially in recent years. 1Indeed, the first time we checked after writing that sentence, we found that they had added a new 232 rule forbidding truckers from texting while driving. (Of course, many of these rules and regulations help protect society and truckers in particular.) 8.1 Perfect Competition 233 What effect do these new fixed costs have on the trucking industry’s market price and quantity? Are individual firms providing more or fewer trucking services? Does the number of firms in the market rise or fall? (As we’ll discuss at the end of the chapter, the answer to one of these questions is surprising.) T o answer questions like these, we need to combine our understanding of demand curves with knowledge about firm and market supply curves to predict industry price, quantity, and profits. We start our analysis of firm behavior by addressing the fundamental question “How much should a firm produce?” To pick a level of output that maximizes its profit, a firm must consider its cost function and how much it can sell at a given price. The amount the firm thinks it can sell depends on the market demand of consumers and on its beliefs about how other firms in the market will behave. As described in Chapter 7, how a firm should approach such issues depends on the market’s structure. We identified four primary market structures—monopoly, oligopoly, monopolistic competition, and perfect competition—that differ based on such attributes as the number of firms in the market, the control firms have over market prices, the ease with which firms can enter and leave the market, and the ability of firms to differentiate their products from those of their rivals. This chapter focuses on perfect competition, a market structure in which there are so many buyers and sellers that each market participant is a price taker, who cannot affect the market’s equilibrium price. Perfect competition is an important market structure for two main reasons. First, a significant part of the economy—including much of agriculture, finance, construction, real estate, wholesale and retail trade, and many service industries—is highly competitive and is well-described by the model of perfect competition. Second, a competitive market is the only market structure that maximizes a commonly used measure of economic well-being (total surplus) and thus serves as a baseline against which to compare the economic outcomes of other market structures. Main Topics 1. Perfect Competition: In a perfectly competitive market, each firm is a price taker, which means the firm faces a horizontal demand curve for its product. In this chapter, we examine four main topics 2. Competition in the Short Run: Short-run marginal costs determine a profit-maximizing, competitive firm’s short-run supply curve and the market supply curve, which, when combined with the market demand curve, determines the competitive equilibrium. 3. Competition in the Long Run: Firm supply, market supply, and the competitive equilibrium may be different in the long run than in the short run because firms can vary inputs that were fixed in the short run. 4. Perfect Competition Maximizes Economic Well-Being: Perfect competition maximizes a widely used measure of economic well-being for society. 8.1 Perfect Competition Perfect competition is a market structure in which buyers and sellers are price takers. A price-taking firm cannot affect the market price for the product it sells. A firm is a price taker if it faces a demand curve for its product that is horizontal at the market price. That is, it can sell as much as it wants at the market price, so it has no 234 CHAPTER 8 Competitive Firms and Markets incentive to lower its price to gain more sales. If it raises its price even slightly, it can sell nothing. Thus, the firm sells its product at the market price. In this section, we discuss how the characteristics of a perfectly competitive market lead to price taking and how much a market can deviate from these characteristics and still be regarded as a competitive market. Characteristics of a Perfectly Competitive Market Perfectly competitive markets have five characteristics that force firms to be price takers: 1. The market consists of many small buyers and sellers. 2. All firms produce identical products. 3. All market participants have full information about price and product characteristics. 4. Transaction costs are negligible. 5. Firms can freely enter and exit the market in the long run. Large Numbers of Buyers and Sellers. If the sellers in a market are small and numerous, no single firm can raise or lower the market price. The more firms in a market, the less any one firm’s output affects the market output and hence the market price. For example, the 107,000 U.S. soybean farmers are price takers. If a typical grower were to drop out of the market, market supply would fall by only 1/107,000 = 0.00093%, so the market price would not be noticeably affected. Each soybean farm can sell as much output as it can produce at the prevailing market equilibrium price, so each farm faces a demand curve that is a horizontal line at the market price. Similarly, perfect competition requires that buyers be price takers as well. In contrast, if firms sell to only a single buyer—such as producers of weapons that are allowed to sell to only the government—then the buyer can set the price and the market is not perfectly competitive. Identical Products. Firms in a perfectly competitive market sell identical or homogeneous products. Consumers do not ask which farm grew a particular Granny Smith apple because they view all Granny Smith apples as essentially identical products. If the products of all firms are identical, it is difficult for any single firm to raise its price above the going price charged by other firms. In contrast, in the automobile market—which is not perfectly competitive—the characteristics of a Ferrari and a Honda Civic differ substantially. These products are differentiated or heterogeneous. Competition from Civics is not in itself a very strong force preventing Ferrari from raising its price. Full Information. If buyers know that different firms are producing identical products and they know the prices charged by all firms, no single firm can unilaterally raise its price above the market equilibrium price. If it tried to do so, consumers would buy the identical product from another firm. However, if consumers are unaware that products are identical or they don’t know the prices charged by other firms, a single firm may be able to raise its price and still make sales. Negligible Transaction Costs. Perfectly competitive markets have very low transaction costs. Buyers and sellers do not have to spend much time and money 8.1 Perfect Competition 235 finding each other or hiring lawyers to write contracts to make a trade. If transaction costs are low, it is easy for a customer to buy from a rival firm if the customer’s usual supplier raises its price. In contrast, if transaction costs are high, customers may absorb a price increase from their traditional supplier to avoid incurring a substantial transaction cost in finding and contracting with a new supplier. Because some consumers prefer to buy a carton of milk at a local convenience store rather than travel several extra miles to a supermarket, the convenience store can charge slightly more than the supermarket without losing all its customers. In some perfectly competitive markets, many buyers and sellers are brought together in a single room or online so that transaction costs are virtually zero. Transaction costs are very low at FloraHolland’s daily plant and cut flower auctions in the Netherlands, which attract 7,000 suppliers and 4,500 buyers from around the world. There are about 125,000 auction transactions every day, with 12 billion cut flowers and 1.3 billion plants trading in a year. Free Entry and Exit. The ability of firms to enter and exit a market freely in the long run leads to a large number of firms in a market and promotes price taking. Suppose a firm could raise its price and make a higher profit. If other firms could not enter the market, this firm would not be a price taker. However, if other firms can quickly and easily enter the market, the higher profit encourages entry by new firms until the price is driven back to the original level. Free exit is also important: If firms can freely enter a market but cannot quickly exit if prices decline, they are reluctant to enter the market in response to a possibly temporary profit opportunity.2 Perfect Competition in the Chicago Mercantile Exchange. The Chicago Mercantile Exchange, where buyers and sellers can trade wheat and other commodities, has the various characteristics of perfect competition including a very large number of many buyers and sellers who are price takers. Anyone can be a buyer or a seller. Indeed, a trader might buy wheat in the morning and sell it in the afternoon. They trade virtually identical products. Buyers and sellers have full information about products and prices, which is posted for everyone to see. Market participants waste no time finding someone who wants to trade and they can easily place buy or sell orders in person, over the telephone, or electronically without paperwork, so transaction costs are negligible. Finally, buyers and sellers can easily enter this market and trade wheat. These characteristics lead to an abundance of buyers and sellers and to price-taking behavior by these market participants. Deviations from Perfect Competition Many markets possess some but not all the characteristics of perfect competition, but they are still highly competitive so that buyers and sellers are, for all practical purposes, price takers. For example, a government may limit entry into a market, but if there are still many buyers and sellers, they may still be price takers. Many cities use zoning laws to limit the number of certain types of stores or motels, yet these cities still have a large number of these firms. Other cities impose moderately large transaction costs on entrants by requiring them to buy licenses, post bonds, 2For example, some governments, particularly in Europe, require firms to give workers six months’ warning before they can exit the market. 236 CHAPTER 8 Competitive Firms and Markets and deal with a slow moving city bureaucracy, yet a significant number of firms enter the market. Similarly, even if only some customers have full information, that may be sufficient to prevent firms from deviating significantly from price taking. For example, tourists do not know the prices at various stores, but locals do and use their knowledge to prevent one store from charging unusually high prices. Economists use the terms competition and competitive more restrictively than do others. To an economist, a competitive firm is a price taker. In contrast, when most people talk about competitive firms, they mean that firms are rivals for the same customers. Even in an oligopolistic market (Chapter 7) with only a few firms, the firms compete for the same customers so they are competitive in this broader sense. From now on, we will use the terms competition and competitive to refer to all markets in which no buyer or seller can significantly affect the market price—they are price takers—even if the market is not perfectly competitive. 8.2 Competition in the Short Run In this section, we examine the profit-maximizing behavior of competitive firms, derive their supply curves, and determine the competitive equilibrium in the short run. In the next section, we examine the same issues in the long run. The short run is a period short enough that at least one input cannot be varied (Chapter 5). Because a firm cannot quickly build a new plant or make other large capital expenditures, a new firm cannot enter a market in the short run. Similarly, a firm cannot fully exit in the short run. It can choose not to produce—to shut down— but it is stuck with some fixed inputs such as a plant or other capital that it cannot quickly sell or assign to other uses. In the long run, all inputs can be varied so firms can enter and fully exit the industry. We treat the short run and the long run separately for two reasons. First, profit-maximizing firms may choose to operate at a loss in the short run, whereas they do not do so in the long run. Second, a firm’s long-run supply curve typically differs from its short-run supply curve. Economists usually assume that all firms—not just competitive firms—want to maximize their profits. This assumption is reasonable for at least two reasons (Chapter 7). First, many owners and managers of firms say that their objective is to maximize profits. Second, firms—especially competitive firms—that do not maximize profit are likely to lose money and be driven out of business. As we showed in Chapter 7, all firms—not just competitive firms—use a two-step decision-making process to determine how to maximize profit: 1. How much to produce. A firm first determines the output that maximizes its profit or minimizes its loss. 2. Whether to produce. Given that it has determined its profit-maximizing output, the firm decides whether to produce this quantity or shut down, producing no output. How Much to Produce As Chapter 7 shows, any operating firm—not just a competitive firm—maximizes its profit or minimizes its loss by setting its output where its marginal profit is zero or, equivalently, where its marginal revenue equals its marginal 8.2 Competition in the Short Run 237 cost: MR(q) = MC(q). 3 A competitive firm can easily determine its marginal revenue. Because it faces a horizontal demand curve, a competitive firm can sell as many units of output as it wants at the market price, p. Thus, a competitive firm’s revenue, R = pq, increases by p if it sells one more unit of output, so its marginal revenue is p. For example, if the firm faces a market price of $1 per unit, its revenue is $5 if it sells 5 units and $6 if it sells 6 units, so its marginal revenue for the sixth unit is $1 = $6 - $5, which is the market price.4 Thus, because a competitive firm’s marginal revenue equals the market price, a profit-maximizing competitive firm produces the amount of output, q, at which the market price, p, equals its marginal cost, MC: p = MC(q). (8.1) To illustrate how a competitive firm maximizes its profit, we examine a representative firm in the highly competitive Canadian lime manufacturing industry. Lime is a nonmetallic mineral used in mortars, plasters, cements, bleaching powders, steel, paper, glass, and other products. The lime plant’s estimated average cost curve, AC, first falls and then rises in panel a of Figure 8.1.5 As always, the marginal cost curve, MC, intersects the average cost curve at its minimum point. If the market price of lime is p = $8 per metric ton, the competitive firm faces a horizontal demand curve (marginal revenue curve) at $8. The MC curve crosses the firm’s demand curve (or price or marginal revenue curve) at point e, where the firm’s output is 284 units (where a unit is a thousand metric tons). Thus at a market price of $8, the competitive firm maximizes its profit by producing 284 units. If the firm produced fewer than 284 units, the market price would be above its marginal cost. As a result, the firm could increase its profit by expanding output because the firm earns more on the next ton, p = $8, than it costs to produce it, MC 6 $8. If the firm were to produce more than 284 units, the market price would be below its marginal cost, MC 7 $8, and the firm could increase its profit by reducing its output. Thus, the competitive firm maximizes its profit by producing that output at which its marginal cost equals its marginal revenue, which is the market price.6 At that 284 units, the firm’s profit is π = $426,000, which is the shaded rectangle in panel a. The length of the rectangle is the number of units sold, q = 284,000 (or 284 3As explained in Chapter 7, if MR 7 MC, then a small increase in quantity causes revenue to rise by more than cost, so maximizing profit requires an increase in output. If MR 6 MC, then maximizing profit requires a decrease in quantity as the reduction in cost exceeds the reduction in revenue. Only if MR = MC is the firm maximizing profit. 4We can use calculus to derive this result. Because R(q) = pq, MR(q) = dR(q)/dq = d(pq)/dq = p. 5The figure is based on Robidoux and Lester’s (1988) estimated variable cost function. In the figure, we assume that the minimum of the average variable cost curve is $5 at 50,000 metric tons of output. Based on information from Statistics Canada, we set the fixed cost so that the average cost is $6 at 140,000 tons. 6The firm chooses its output level to maximize its total profit rather than its average profit per ton. If the firm were to produce 140 units, where its average cost is minimized at $6, the firm would maximize its average profit at $2, but its total profit would be only $280,000. Although the firm gives up 50¢ in profit per ton when it produces 284 units instead of 140 units, it more than makes up for that lost profit per ton by selling an extra 144 units. At $1.50 profit per ton, the firm’s total profit is $426,000, which is $146,000 higher than it is at 140 units. 238 CHAPTER 8 Competitive Firms and Markets F IG U RE 8. 1 How a Competitive Firm Maximizes Profit (a) A competitive lime manufacturing firm maximizes its profit at π* = $426,000 where its marginal revenue, MR, which is the market price, p = $8, equals its marginal cost, MC. (b) The corresponding profit curve reaches its peak at 284 units of lime. Estimated cost curves are based on Robidoux and Lester (1988). p, $ per ton (a) 10 MC AC e 8 p = MR π = $426,000 6.50 6 0 140 284 q, Thousand metric tons of lime per year Cost, revenue, Thousand $ (b) 426 π (q) 0 140 284 q, Thousand metric tons of lime per year –100 units). The height of the rectangle is the firm’s average profit per unit. Because the firm’s profit is its revenue, R(q) = pq, minus its cost, π(q) = R(q) - C(q), its average profit per unit is the difference between the market price (or average revenue), p = R(q)/q = pq/q, and its average cost, AC = C(q)/q: π(q) R(q) - C(q) R(q) C(q) = = = p - AC. q q q q (8.2) At 284 units, the lime firm’s average profit per unit is $1.50 = p - AC(284) = $8 - $6.50, and the firm’s profit is π = $1.50 * 284,000 = $426,000. Panel b shows that this profit is the maximum possible profit because it is the peak of the profit curve. 8.2 Competition in the Short Run 239 If a competitive firm’s cost increases due to an increase in the price of a factor of production or a tax, the firm’s manager can quickly determine by how much to adjust output by calculating how the firm’s marginal cost has changed and applying the profit-maximization rule. Suppose that the Canadian province of Manitoba imposes a specific (per-unit) tax of t per ton of lime produced in the province. There is only one lime-producing firm in Manitoba, so the tax affects only that firm and hence has virtually no effect on the market price. If the tax is imposed, how should the Manitoba firm change its output level to maximize its profit, and how does its maximum profit change? Q& A 8.1 Answer 1. Show how the tax shifts the marginal cost and average cost curves. The firm’s before-tax marginal cost curve is MC 1 and its before-tax average cost curve is AC 1. Because the specific tax adds t to the per-unit cost, it shifts the after-tax marginal cost curve up to MC 2 = MC 1 + t and the after-tax average cost curve to AC 2 = AC 1 + t. p, $ per unit MC 2 = MC 1 + t MC1 AC 2 = AC1 + t AC 1 e2 p e1 p = MR A AC 2(q2) t B AC 1(q1) t q2 q1 q, Units per year 2. Determine the before-tax and after-tax equilibria and the amount by which the firm adjusts its output. Where the before-tax marginal cost curve, MC 1, hits the horizontal demand curve, p, at e1, the profit-maximizing quantity is q1. The after-tax marginal cost curve, MC 2, intersects the demand curve, p, at e2, where the profit-maximizing quantity is q2. Thus, in response to the tax, the firm produces q1 - q2 fewer units of output. 3. Show how the profit changes after the tax. Because the market price is constant but the firm’s average cost curve shifts upward, the firm’s profit at every output level falls. The firm sells fewer units (because of the increase in MC) and makes less profit per unit (because of the increase in AC). The after-tax profit is area A = π2 = [p - AC 2(q2)]q2, and the before-tax profit is area A + B = π1 = [p - AC 1(q1)]q1, so profit falls by area B due to the tax. 240 CHAPTER 8 Competitive Firms and Markets Using Calculus We can use calculus to solve the problem in Q&A 8.1. The competitive firm’s profit after the specific tax t is imposed is Profit Maximization with a Specific Tax π = pq - [C(q) + tq], where C(q) is the firm’s before-tax cost and C(q) + tq is its after-tax cost. We obtain a necessary condition for the firm to maximize its after-tax profit by taking the first derivative of profit with respect to quantity and setting it equal to zero: dC(q) d(pq) d[C(q) + tq] dπ = = p - J + t R = p - [MC + t] = 0. dq dq dq dq Thus, the competitive firm maximizes its profit by choosing q such that its after-tax marginal cost, MC + t, equals the market price. Whether to Produce Once a firm determines the output level that maximizes its profit or minimizes its loss, it must decide whether to produce that output level or to shut down and produce nothing. This decision is easy for the lime firm in Figure 8.1 because, at the output that maximizes its profit, it makes a positive profit. However, the question remains whether a firm should shut down if it is making a loss in the short run. In Chapter 7, we showed that all firms—not just competitive firms—use the same shutdown rule: The firm shuts down only if it can reduce its loss by doing so. Equivalently, the firm shuts down only if its revenue is less than its avoidable variable cost (VC): R 6 VC. If the firm shuts down, it does not incur the variable cost, so its only loss is its unavoidable fixed cost (F). For a competitive firm, this rule is R = pq 6 VC. Dividing both sides of this inequality by output, we find that a competitive firm shuts down only if the market price is less than its average variable cost: p 6 AVC = VC/q. We illustrate the logic behind this rule using our lime firm example. We look at three cases where the market price is (1) above the minimum average cost (AC), (2) less than the minimum average cost but at least equal to or above the minimum average variable cost, or (3) below the minimum average variable cost. The Market Price Is Above Minimum AC. If the market price is above the firm’s average cost at the quantity that it’s producing, the firm makes a profit and so it operates. In panel a of Figure 8.1, the competitive lime firm’s average cost curve reaches its minimum of $6 per ton at 140 units. Thus, if the market price is above $6, the firm makes a profit of p - AC on each unit it sells and operates. In the figure, the market price is $8, and the firm makes a profit of $426,000. The Market Price Is Between the Minimum AC and the Minimum AVC. The tricky case is when the market price is less than the minimum average cost but at least as great as the minimum average variable cost. If the price is in this range, the firm makes a loss, but it reduces its loss by operating rather than shutting down. Figure 8.2 (which reproduces the marginal and average cost curves from panel a of Figure 8.1 and adds the average variable cost curve) illustrates this case for the lime firm. The lime firm’s average cost curve reaches a minimum of $6 at 140 units, while its average variable cost curve hits its minimum of $5 at 50 units. If the market price is between $5 and $6, the lime firm loses money (its profit is negative) because the price is less than its AC, but the firm does not shut down. 8.2 Competition in the Short Run 241 The competitive lime manufacturing plant operates if price is above the minimum of the average variable cost curve, point a, at $5. With a market price of $5.50, the firm produces 100 units because that price is above AVC(100) = $5.14, so the firm more than covers its out-of-pocket, variable costs. At that price, the firm makes a loss of area A = $62,000 because the price is less than the average cost of $6.12. If it shuts down, its loss is its fixed cost, area A + B = $98,000. Thus, the firm does not shut down. p, $ per ton F IG U RE 8. 2 The Short-Run Shutdown Decision MC AC b 6.12 6.00 AVC A = $62,000 5.50 B = $36,000 5.14 5.00 0 p e a 50 100 140 q, Thousand metric tons of lime per year For example, if the market price is $5.50, the firm minimizes its loss by producing 100 units where the marginal cost curve crosses the price line. At 100 units, the average cost is $6.12, so the firm’s loss is -62¢ = p - AC(100) = $5.50 - $6.12 on each unit that it sells. Why does the firm produce given that it is making a loss? The reason is that the firm reduces its loss by operating rather than shutting down because its revenue exceeds its variable cost—or equivalently, the market price exceeds its average variable cost. If the firm shuts down in the short run, it incurs a loss equal to its fixed cost of $98,000, which is the sum of rectangles A and B.7 If the firm operates and produces q = 100 units, its average variable cost is AVC = $5.14, which is less than the market price of p = $5.50 per ton. It makes 36¢ = p - AVC = $5.50 - $5.14 more on each ton than its average variable cost. The difference between the firm’s revenue and its variable cost, R - VC, is the rectangle B = $36,000, which has a length of 100 thousand tons and a height of 36¢. Thus, if the firm operates, it loses only $62,000 (rectangle A), which is less than its loss if it shuts down, $98,000. The firm makes a smaller loss by operating than by shutting down because its revenue more than covers its variable cost and hence helps to reduce the loss from the fixed cost. The Market Price Is Less than the Minimum AVC. If the market price dips below the minimum of the average variable cost, $5 in Figure 8.2, then the firm should shut down in the short run. At any price less than the minimum average variable cost, the firm’s revenue is less than its variable cost, so it makes a greater 7From Chapter 6, we know that the average cost is the sum of the average variable cost and the average fixed cost, AC = AVC + F/q. Thus, the gap between the average cost and the average variable cost curves at any given output is AC - AVC = F/q. Consequently, the height of the rectangle A + B is AC(100) - AVC(100) = F/100, and the length of the rectangle is 100 units, so the area of the rectangle is F, or $98,000 = $62,000 + $36,000. 242 CHAPTER 8 Competitive Firms and Markets loss by operating than by shutting down because it loses money on each unit sold in addition to the fixed cost that it loses if it shuts down. In summary, a competitive firm uses a two-step decision-making process to maximize its profit. First, the competitive firm determines the output that maximizes its profit or minimizes its loss when its marginal cost equals the market price (which is its marginal revenue): p = MC. Second, the firm chooses to produce that quantity unless it would lose more by operating than by shutting down. The competitive firm shuts down in the short run only if the market price is less than the minimum of its average variable cost, p 6 AVC. Mini-Case Oil, Oil Sands, and Oil Shale Shutdowns Oil production starts and stops in the short run as the market price fluctuates. In 1998–1999 when oil prices were historically low, 74,000 of the 136,000 oil wells in the United States temporarily shut down or were permanently abandoned. At the time, Terry Smith, the general manager of Tidelands Oil Production Company, who had shut down 327 of his company’s 834 wells, said that he would operate these wells again when price rose above $10 a barrel—his minimum average variable cost. Getting oil from oil wells is relatively easy. It is harder and more costly to obtain oil from other sources, so firms that use those alternative sources have a higher minimum average variable cost— higher shutdown points—and hence shut down at a higher price than companies that pump oil from wells. It might surprise you to know that Canada has the third-largest known oil reserves in the world, 175 billion barrels, trailing only Saudi Arabia and Venezuela and far exceeding Iraq in fourth place. Yet you rarely hear about Canada’s vast oil reserves because 97% of those reserves are in oil sands, which cover an area the size of Florida. Oil sands are a mixture of heavy petroleum (bitumen), water, and sandstone. Extracting oil from oil sands is expensive and causes significant pollution in the production process. To liberate four barrels of crude oil from the sands, a processor must burn the equivalent of a fifth barrel. With the technology available in 2013, two tons of oil sands yielded only a single barrel (42 gallons) of oil. The first large oil sands mining began in the 1960s, but because oil prices were often less than the $25-per-barrel average variable cost of recovering oil from the sands at that time, production was frequently shut down. In recent years, however, technological improvements in the production process have lowered the average variable cost to $18 a barrel. That, coupled with higher oil prices, has led to continuous oil sands production without shutdowns. As of 2013, more than 50 oil companies had operations in the Canadian oil sands, including major international producers such as Exxon, BP (formerly British Petroleum), and 8.2 Competition in the Short Run 243 Royal Dutch Shell, major Canadian producers such as Suncor and Husky, and companies from China, Japan, and South Korea. The huge amounts of oil hidden in oil sands may be dwarfed by those found in oil shale, which is sedimentary rock containing oil. According to current estimates, oil shale deposits in Colorado and neighboring areas in Utah and Wyoming contain 800 billion recoverable barrels, the equivalent of 40 years of U.S. oil consumption. The United States has between 1 and 2 trillion recoverable barrels from oil shale, which is at least four times Saudi Arabia’s proven reserves of crude oil, which are in underground pools. A federal task force report concluded that the United States will be able to produce 3 million barrels of oil a day from oil shale and sands by 2035. Shell Oil reports that its average variable cost of extracting oil from shale is $30 a barrel in Colorado. In recent years, the lowest price for world oil was $39 a barrel on December 12, 2008. Since then prices have risen significantly, reaching $100 per barrel in early 2011 and remaining close to or above that level through early 2013. Therefore, oil shale production has become profitable and extraction is occurring. The Short-Run Firm Supply Curve We just demonstrated how a competitive firm chooses its output for a given market price in a way that maximizes its profit or minimizes its losses. By repeating this analysis at different possible market prices, we can show how the amount the competitive firm supplies varies with the market price. As the market price increases from p1 = $5 to p2 = $6 to p3 = $7 to p4 = $8, the lime firm increases its output from 50 to 140 to 215 to 285 units per year, as Figure 8.3 shows. The profit-maximizing output at each market price is determined As the market price increases, the lime manufacturing firm produces more output. The change in the price traces out the marginal cost (MC ) curve of the firm. The firm’s short-run supply (S) curve is the MC curve above the minimum of its AVC curve (at e1). p, $ per ton F IG U RE 8. 3 How the Profit-Maximizing Quantity Varies with Price S e4 8 p4 e3 AC 7 p3 AVC e2 p2 6 e1 p1 5 MC 0 q1 = 50 q2 = 140 q3 = 215 q4 = 285 q, Thousand metric tons of lime per year 244 CHAPTER 8 Competitive Firms and Markets by the intersection of the relevant demand curve—market price line—and the firm’s marginal cost curve, as equilibria e1 through e4 illustrate. That is, as the market price increases, the equilibria trace out the marginal cost curve. However, if the price falls below the firm’s minimum average variable cost at $5, the firm shuts down. Thus, the competitive firm’s short-run supply curve is its marginal cost curve above its minimum average variable cost. The firm’s short-run supply curve, S, is a solid red line in the figure. At prices above $5, the short-run supply curve is the same as the marginal cost curve. The supply is zero when price is less than the minimum of the AVC curve of $5. (From now on, to keep the graphs as simple as possible, we will not show the supply curve at prices below the minimum AVC.) The Short-Run Market Supply Curve The market supply curve is the horizontal sum of the supply curves of all the individual firms in the market. In the short run, the maximum number of firms in a market, n, is fixed because new firms need time to enter the market. If all the firms in a competitive market are identical, each firm’s costs are identical, so their supply curves are identical, and the market supply at any price is n times the supply of an individual firm. If the firms have different costs functions, their supply curves and shutdown points differ. Consequently, the market supply curve reflects a different number of firms operating at various prices even in the short run. We examine competitive markets first with firms that have identical costs and then with firms that have different costs. Short-Run Market Supply with Identical Firms. To illustrate how to construct a short-run market supply curve, we suppose, for graphical simplicity, that the lime manufacturing market has n = 5 competitive firms with identical cost curves. Panel a of Figure 8.4 plots the short-run supply curve, S1, of a typical F IG U RE 8. 4 Short-Run Market Supply with Five Identical Lime Firms (a) The short-run supply curve, S1, for a typical lime manufacturing firm is its MC above the minimum of its AVC. (b) The market supply curve, S5, is the horizontal (b) Market S1 7 6.47 AVC p, $ per ton p, $ per ton (a) Firm sum of the supply curves of each of the five identical firms. The curve S 4 shows what the market supply curve would be if there were only four firms in the market. 7 S5 5 5 140 175 q, Thousand metric tons of lime per year S3 6.47 6 MC 50 S2 S4 6 0 S1 0 50 150 250 100 200 700 Q, Thousand metric tons of lime per year 8.2 Competition in the Short Run 245 firm—the MC curve above the minimum AVC—where the horizontal axis shows the firm’s output, q, per year. Panel b illustrates the competitive market supply curve, the dark line S5, where the horizontal axis is market output, Q, per year. The price axis is the same in the two panels. If the market price is less than $5 per ton, no firm supplies any output, so the market supply is zero. At $5, each firm is willing to supply q = 50 units, as in panel a. Consequently, the market supply is Q = 5q = 250 units in panel b. At $6 per ton, each firm supplies 140 units, so the market supply is 700 ( = 5 * 140) units. Suppose, however, that there were fewer than five firms in the short run. The light-color lines in panel b show the market supply curves for various other numbers of firms. The market supply curve is S1 if there is one price-taking firm, S2 with two firms, S3 with three firms, and S4 with four firms. The market supply curve flattens as the number of firms in the market increases because the market supply curve is the horizontal sum of more and more upward-sloping firm supply curves.8 Thus, the more identical firms producing at a given price, the flatter the short-run market supply curve at that price. The flatter the supply curve is at a given quantity, the more elastic is the supply curve. As a result, the more firms in the market, the less the price has to increase for the short-run market supply to increase substantially. Consumers pay $6 per ton to obtain 700 units of lime if there are five firms, but they must pay $6.47 per ton to obtain that much with only four firms. As the number of firms grows very large, the market supply curve approaches a horizontal line at $5. Short-Run Market Supply with Firms That Differ. If the firms in a competitive market have different minimum average variable costs, not all firms produce at every price, a situation that affects the shape of the short-run market supply curve. Suppose that the only two firms in the lime market are our typical lime firm with a supply curve of S1 and another firm with a higher marginal and minimum average cost and the supply curve of S2 in Figure 8.5. The first firm produces if the market price is at least $5, whereas the second firm does not produce unless the price is $6 or more. At $5, the first firm produces 50 units, so the quantity on the market supply curve, S, is 50 units. Between $5 and $6, only the first firm produces, so the market supply, S, is the same as the first firm’s supply, S1. At and above $6, both firms produce, so the market supply curve is the horizontal summation of their two individual supply curves. For example, at $7, the first firm produces 215 units, and the second firm supplies 100 units, so the market supply is 315 units. As with the identical firms, where both firms are producing, the market supply curve is flatter than that of either firm. Because the second firm does not produce at as low a price as the first firm, the short-run market supply curve has a steeper slope (less elastic supply) at relatively low prices than it would if the firms were identical. When the firms differ, only the low-cost firm supplies goods at relatively low prices. As the price rises, the other, higher-cost firm starts supplying, creating a stair-like market supply curve. The more suppliers there are with differing costs, the more steps there are in the market supply curve. As price rises and more firms supply the good, the market supply curve flattens, so it takes a smaller increase in price the figure, if the price rises by Δp = 47¢ from $6 to $6.47 per ton, each firm increases its output by Δq = 35 tons, so the slope (measured in cents per ton) of its supply curve over that range is Δp/Δq = 47/35 ≈ 1.34. With two firms, Δq = 70, so the slope is 47/70 ≈ 0.67. Similarly, the slope is 47/105 ≈ 0.45 with three firms, 0.33 with four firms, and 0.27 with five firms. Although not shown in the figure, the slope is 0.13 with 10 firms and 0.013 with 100 firms. 8In 246 CHAPTER 8 Competitive Firms and Markets The supply curve S1 is the same as for the typical lime firm in Figure 8.3. A second firm has an MC that lies to the left of the original firm’s cost curve and a higher minimum of its AVC. Thus, its supply curve, S2, lies above and to the left of the original firm’s supply curve, S1. The market supply curve, S, is the horizontal sum of the two supply curves. When price is $6 or higher, both firms produce, and the market supply curve is flatter than the supply curve of either individual firm. p, $ per ton F IG U RE 8. 5 Short-Run Market Supply with Two Different Lime Firms S2 8 S1 S 7 6 5 0 25 50 100 140 165 215 315 450 q, Q, Thousand metric tons of lime per year to increase supply by a given amount. Stated the other way, the more firms differ in costs, the steeper the market supply curve at low prices. Differences in costs are one explanation for why some market supply curves are upward sloping. Short-Run Competitive Equilibrium By combining the short-run market supply curve and the market demand curve, we can determine the short-run competitive equilibrium. We first show how to determine the equilibrium in the lime market, and we then examine how the equilibrium changes when firms are taxed. Suppose that there are five identical firms in the short-run equilibrium in the lime manufacturing industry. Panel a of Figure 8.6 shows the short-run cost curves and the supply curve, S1, for a typical firm, and panel b shows the corresponding short-run competitive market supply curve, S. In panel b, the initial demand curve D1 intersects the market supply curve at E1, the market equilibrium. The equilibrium quantity is Q1 = 1,075 units of lime per year, and the equilibrium market price is $7. In panel a, each competitive firm faces a horizontal demand curve at the equilibrium price of $7. Each price-taking firm chooses its output where its marginal cost curve intersects the horizontal demand curve at e1. Because each firm is maximizing its profit at e1, no firm wants to change its behavior, so e1 is the firm’s equilibrium. In panel a, each firm makes a short-run profit of area A + B = $172,000, which is the average profit per ton, p - AC = $7 - $6.20 = 80¢, times the firm’s output, q1 = 215 units. The equilibrium market output, Q1, is the number of firms, n, times the equilibrium output of each firm: Q1 = nq1 = 5 * 215 units = 1,075 units (panel b). Now suppose that the demand curve shifts to D2. The new market equilibrium is E2, where the price is only $5. At that price, each firm produces q = 50 units, and 8.3 Competition in the Long Run 247 F IG U RE 8. 6 Short-Run Competitive Equilibrium in the Lime Market (a) The short-run supply curve is the marginal cost above minimum average variable cost of $5. At a price of $5, each firm makes a short-run loss of (p - AC )q = ($5 - $6.97) * 50,000 = - $98,500, area A + C. At a price of $7, the short-run profit of a typical lime firm is (p - AC)q = ($7 - $6.20) * 215,000 = $172,000, (b) Market 8 p, $ per ton p, $ per ton (a) Firm area A + B. (b) If there are five firms in the lime market in the short run, so the market supply is S, and the market demand curve is D1, then the short-run equilibrium is E1, the market price is $7, and market output is Q1 = 1,075 units. If the demand curve shifts to D2, the market equilibrium is p = $5 and Q2 = 250 units. S1 e1 7 6.97 A S 8 D1 7 E1 AC B D2 6.20 6 AVC 6 C 5 0 5 e2 q2 = 50 q1 = 215 0 E2 Q2 = 250 q, Thousand metric tons of lime per year Q1 = 1,075 Q, Thousand metric tons of lime per year market output is Q = 250 units. In panel a, each firm loses $98,500, area A + C, because it earns (p - AC) = ($5 - $6.97) = -$1.97 per unit and it sells q2 = 50 units. However, such a firm does not shut down because price equals the firm’s average variable cost, so the firm is covering its out-of-pocket expenses. 8.3 Competition in the Long Run I think there is a world market for about five computers. —Thomas J. Watson, IBM chairman, 1943 In the long run, competitive firms can vary inputs that were fixed in the short run and firms can enter and exit the industry freely, so the long-run firm and market supply curves differ from the short-run curves. After briefly looking at how a firm determines its long-run supply curve to maximize its profit, we examine the relationship between short-run and long-run market supply curves and competitive equilibria. Long-Run Competitive Profit Maximization The firm’s two profit-maximizing decisions—how much to produce and whether to produce at all—are simpler in the long run than in the short run because, in the long run, all costs are avoidable. The firm chooses the quantity that maximizes its profit using the same rules as in the short run. The firm picks the quantity that maximizes long-run profit, the 248 CHAPTER 8 Competitive Firms and Markets difference between revenue and long-run cost. Equivalently, it operates where long-run marginal profit is zero—where marginal revenue (price) equals long-run marginal cost. After determining the output level, q*, that maximizes its profit or minimizes its loss, the firm decides whether to produce or shut down. The firm shuts down if its revenue is less than its avoidable cost. Because all costs are avoidable in the long run, the firm shuts down if it would make an economic loss by operating. The Long-Run Firm Supply Curve A firm’s long-run supply curve is its long-run marginal cost curve above the minimum of its long-run average cost curve (because all costs are avoidable in the long run). The firm is free to choose its capital in the long run, so the firm’s long-run supply curve may differ substantially from its short-run supply curve. The firm chooses a plant size to maximize its long-run economic profit in light of its beliefs about the future. If its forecast is wrong, it may be stuck with a plant that is too small or too large for its level of production in the short run. The firm acts to correct this mistake in plant size in the long run. Mini-Case The Size of Ethanol Processing Plants When a large number of firms initially built ethanol processing plants, they built relatively small ones. When the ethanol market took off in the first half decade of the twenty-first century, with the price reaching a peak of $4.23 a gallon in June 2006, many firms built larger plants or greatly increased their plant size. Then, with the more recent collapse of that market—the price fell below $3 and often below $1.50 from 2007 through 2012—many firms either closed their plants or reduced their size. The capacity of plants under construction or expansion went from 3,644 million gallons per year in 2005 to 5,635 in 2007, but since then the size has fallen to 1,432 in 2010 and 522 in 2011. The Long-Run Market Supply Curve The competitive market supply curve is the horizontal sum of the supply curves of the individual firms in both the short run and the long run. Because the maximum number of firms in the market is fixed in the short run, we add the supply curves of a known number of firms to obtain the short-run market supply curve. The only way for the market to supply more output in the short run is for existing firms to produce more. However, in the long run, firms can enter or leave the market. Thus, before we can add all the relevant firm supply curves to obtain the long-run market supply curve, we need to determine how many firms are in the market at each possible market price. We now look in detail at how market entry affects long-run market supply. To isolate the role of entry, we derive the long-run market supply curve, assuming that the price of inputs remains constant as market output increases. Entry and Exit. The number of firms in a market in the long run is determined by the entry and exit of firms. In the long run, each firm decides whether to enter or exit depending on whether it can make a long-run profit. 8.3 Competition in the Long Run 249 In some markets, firms face significant costs to enter, such as large start-up costs, or barriers to entry, such as a government restriction. For example, many city governments limit the number of cabs, creating an insurmountable barrier that prevents additional taxis from entering. Similarly, patent protection prevents new firms from producing the patented product until the patent expires. However, in perfectly competitive markets, firms can enter and exit freely in the long run, which is referred to as free entry and exit. For example, many construction firms that provide only labor services enter and exit a market several times a year. In the United States, an estimated 198,000 new firms began operations and 187,000 firms exited in the third quarter of 2011.9 The annual rates of entry and exit of such firms are both about 10% of the total number of firms per year. In such markets, a shift of the market demand curve to the right attracts firms to enter. For example, if there were no government regulations, the market for taxicabs would have free entry and exit. Car owners could enter or exit the market quickly. If the demand curve for cab rides shifted to the right, the market price would rise, and existing cab drivers would make unusually high profits in the short run. Seeing these profits, other car owners would enter the market, causing the market supply curve to shift to the right and the market price to fall. Entry would continue until he last firm to enter—the marginal firm—makes zero long-run profit. Similarly, if the demand curve shifts to the left so that the market price drops, firms suffer losses. Firms with minimum average costs above the new, lower market price exit the market. Firms continue to leave the market until the next firm considering leaving, the marginal firm, is again earning a zero long-run profit. Thus, in a market with free entry and exit: ◗ A firm enters the market if it can make a long-run profit, π 7 0. ◗ A firm exits the market to avoid a long-run loss, π 6 0. If firms in a market are making zero long-run profit, they are indifferent between staying in the market and exiting. We presume that if they are already in the market, they stay in the market when they are making zero long-run profit. Mini-Case Fast-Food Firms’ Entry in Russia American fast-food restaurants are flooding into Russia. When McDonald’s opened its first restaurant in Pushkin Square in 1990, workers greeted gigantic lines of customers. Today, it has 279 restaurants in Russia. For years, McDonald’s faced little western competition, despite the popularity of western fast food. The average bill at a Russian fast-food outlet is $8.92 compared to $6.50 in the United States (even though Russian incomes are about one-sixth U.S. incomes). Belatedly recognizing the profit opportunities, other chains are flooding into Russia. Burger King opened 22 restaurants in just two years, Carl’s Jr. has 17 restaurants in just two cities, Wendy’s has 2 restaurants and plans to have 180 throughout Russia by 2020, Subway has about 200 shops under several franchisees, and Yum Brands (which owns KFC, Pizza Hut, and Taco Bell) has about 350 restaurants in Russia. Moscow is particularly ripe for entry by pizza restaurants. With a population of 13 million, it has only about 300 pizza restaurants. In contrast, Manhattan, with a population only about a tenth as large (1.6 million) has 4,000 pizza joints. 9www.bls.gov/news.release/cewbd.t08.htm (viewed March 1, 2013). 250 CHAPTER 8 Competitive Firms and Markets Christopher Wynne, an American who is fluent in Russian and gained Russian expertise researching arms proliferation, left his original career to open pizza restaurants in Russia. He bought 51% of the Papa John’s Russian franchise. Although he competes with the U.S. chains Sbarro and Domino’s and a Russian chain, Pizza Fabrika, among others, he says, “I could succeed in my sleep there is so much opportunity here.” In 2011, Mr. Wynne opened his twenty-fifth Papa John’s outlet in Russia, doubling the number from the previous year. Nineteen are in Moscow. Each restaurant costs about $400,000 to open, but a restaurant can start earning an operating profit in three months. Mr. Wynne will continue opening outlets until the marginal restaurant earns zero economic profit. Long-Run Market Supply with Identical Firms and Free Entry. The long-run market supply curve is flat at the minimum of long-run average cost if firms can freely enter and exit the market, an unlimited number of firms have identical costs, and input prices are constant. This result follows from our reasoning about the short-run supply curve, in which we showed that the market supply curve becomes flatter as more firms enter the market. With a large number of firms in the market in the long run, the market supply curve is effectively flat. The long-run supply curve of a typical vegetable oil mill, S1 in panel a of Figure 8.7, is the long-run marginal cost curve above a minimum long-run average cost of $10. Because each firm shuts down if the market price is below $10, the long-run market supply curve is zero at a price below $10. If the price rises above $10, firms are making positive profits, so new firms enter, expanding market output until profits are driven F IG U RE 8. 7 Long-Run Firm and Market Supply with Identical Vegetable Oil Firms (a) The long-run supply curve of a typical vegetable oil mill, S1, is the long-run marginal cost curve above the minimum average cost of $10. (b) The long-run market supply curve is horizontal at the minimum of the (a) Firm long-run minimum average cost of a typical firm. Each firm produces 150 units, so market output is 150n, where n is the number of firms. S1 LRAC 10 p, $ per unit p, $ per unit (b) Market 10 Long-run market supply LRMC 0 150 0 q, Hundred metric tons of oil per year Q, Hundred metric tons of oil per year 8.3 Competition in the Long Run 251 to zero, where price is again $10. The long-run market supply curve in panel b is a horizontal line at the minimum long-run average cost of the typical firm, $10. At a price of $10, each firm produces q = 150 units (where one unit equals 100 metric tons). Thus, the total output produced by n firms in the market is Q = nq = n * 150 units. Extra market output is obtained by new firms entering the market. In summary, the long-run market supply curve is horizontal if the market has free entry and exit, an unlimited number of firms have identical costs, and input prices are constant. As we show next, when these strong assumptions do not hold, the long-run market supply curve typically slopes upward but may slope downward. We examine two reasons why a long-run market supply curve is not flat: limited entry and differences in cost functions across firms. In addition, although we do not demonstrate this result, there is a third reason why long-run supply curves may slope up (or down), which is that input prices rise (or fall) when output increases. Long-Run Market Supply When Entry Is Limited. If the number of firms in a market is limited in the long run, the market supply curve slopes upward. The number of firms is limited if the government restricts that number, if all firms need a scarce resource, or if entry is costly. An example of a scarce resource is the limited number of lots on which a luxury beachfront hotel can be built in Miami. High entry costs restrict the number of firms in a market because firms enter only if the long-run economic profit is greater than the cost of entering. The only way to get more output if the number of firms is limited is for existing firms to produce more. Because individual firms’ supply curves slope upward, the long-run market supply curve is also upward sloping. The reasoning is the same as in the short run, as panel b of Figure 8.4 illustrates, given that no more than five firms can enter. The market supply curve is the upward-sloping S5 curve, which is the horizontal sum of the five firms’ upward-sloping marginal cost curves above minimum average cost. Long-Run Market Supply When Firms Differ. A second reason why some long-run market supply curves slope upward is that firms differ. Firms with relatively low minimum long-run average costs are willing to enter the market at lower prices than others, resulting in an upward-sloping long-run market supply curve (similar to the short-run example in Figure 8.5). Suppose that a market has a number of low-cost firms and other higher-cost firms. If lower-cost firms can produce as much output as the market wants, only low-cost firms produce, and the long-run market supply curve is horizontal at the minimum of the low-cost firm’s average cost curve. The long-run supply curve is upward sloping only if lower-cost firms cannot produce as much output as the market demands because each of these firms has a limited capacity and the number of these firms is limited. Mini-Case Upward-Sloping Long-Run Supply Curve for Cotton Many countries produce cotton. Production costs differ among countries because of differences in the quality of land, rainfall, costs of irrigation, costs of labor, and other factors. The length of each step-like segment of the long-run supply curve of cotton in the graph is the quantity produced by the labeled country. The amount that CHAPTER 8 Competitive Firms and Markets the low-cost countries can produce is limited, so we observe production by the higher-cost countries if the market price is sufficiently high. Price, $ per kg 252 Iran 1.71 S United States 1.56 Nicaragua, Turkey 1.43 Brazil 1.27 1.15 1.08 0.71 0 Australia Argentina Pakistan 1 2 3 4 5 6 6.8 Cotton, billion kg per year The height of each segment of the supply curve is the typical minimum average cost of production in that country. The average cost of production in Pakistan is less than half that in Iran. The supply curve has a step-like appearance because we are assuming that average cost is constant within a given country, up to capacity. As the market price rises, the number of countries producing rises. At market prices below $1.08 per kilogram, only Pakistan produces. If the market price is below $1.50, the United States and Iran do not produce. If the price increases to $1.56, the United States supplies a large amount of cotton. In this range of the supply curve, supply is elastic. For Iran to produce, the price has to rise to $1.71. Price increases in that range result in only a relatively small increase in supply. Thus, the supply curve is relatively inelastic at prices above $1.56. Long-Run Competitive Equilibrium The intersection of the long-run market supply and demand curves determines the long-run competitive equilibrium. With identical firms, constant input prices, and free entry and exit, the long-run competitive market supply is horizontal at minimum long-run average cost, so the equilibrium price equals long-run average cost. A shift in the demand curve affects only the equilibrium quantity and not the equilibrium price, which remains constant at the minimum of long-run average cost. The market supply curve is different in the short run than in the long run, so the long-run competitive equilibrium differs from the short-run equilibrium. The relationship between the short- and long-run equilibria depends on where the market demand curve crosses the short- and long-run market supply curves. Figure 8.8 8.3 Competition in the Long Run 253 F IG U RE 8. 8 The Short-Run and Long-Run Equilibria for Vegetable Oil (a) A typical vegetable oil mill produces where its MR or price equals its MC, so it is willing to produce 150 units of oil at a price of $10, or 165 units at $11. (b) The short-run market supply curve, SSR, is the horizontal sum of 20 individual firms’ short-run marginal cost curves above minimum average variable cost, $7. The long-run market supply curve, SLR, is p, $ per ton MC AC f2 11 10 p, $ per ton (b) Market (a) Firm D1 D2 S SR AVC e F2 11 10 f1 7 0 horizontal at the minimum average cost, $10. If the demand curve is D1, in the short-run equilibrium, F1, 20 firms sell 2,000 units of oil at $7. In the long-run equilibrium, E1, 10 firms sell 1,500 units at $10. If demand is D2, the short-run equilibrium is F2 ($11, 3,300 units, 20 firms) and the long-run equilibrium is E2 ($10, 3,600 units, 24 firms). E2 S LR E1 F1 7 100 150 165 q, Hundred metric tons of oil per year 0 1,500 2,000 3,300 3,600 Q, Hundred metric tons of oil per year illustrates this point using the short- and long-run supply curves for the vegetable oil mill market. The short-run firm supply curve for a typical firm in panel a is the marginal cost above the minimum of the average variable cost, $7. At a price of $7, each firm produces 100 units, so the 20 firms in the market in the short run collectively supply 2,000 (= 20 * 100) units of oil in panel b. At higher prices, the short-run market supply curve slopes upward because it is the horizontal summation of the firm’s upward-sloping marginal cost curves. We assume that the firms use the same size plant in the short and long run so that the minimum average cost is $10 in both the short and long run. Because all firms have the same costs and can enter freely, the long-run market supply curve is flat at the minimum average cost, $10, in panel b. At prices between $7 and $10, firms supply goods at a loss in the short run but not in the long run. If the market demand curve is D1, the short-run market equilibrium, F1, is below and to the right of the long-run market equilibrium, E1. This relationship is reversed if the market demand curve is D2.10 In the short run, if the demand is as low as D1, the market price in the short-run equilibrium, F1, is $7. At that price, each of the 20 firms produces 100 units, at f1 in panel a. The firms lose money because the price of $7 is below average cost at 100 units. These losses drive some of the firms out of the market in the long run, so market output falls and the market price rises. In the long-run equilibrium, E1, price 10Using data from Statistics Canada, we estimate that the elasticity of demand for vegetable oil is -0.8. Both D1 and D2 are constant -0.8 elasticity demand curves, but the demand at any price on D2 is 2.4 times that on D1. 254 CHAPTER 8 Competitive Firms and Markets is $10, and each firm produces 150 units, e, and breaks even. As the market demands only 1,500 units, only 10 (= 1,500/150) firms produce, so half the firms that produced in the short run exit the market.11 Thus, with the D1 demand curve, price rises and output falls in the long run. If demand expands to D2, in the short run, each of the 20 firms expands its output to 165 units, f2, and the price rises to $11, where the firms make profits: The price of $11 is above the average cost at 165 units. These profits attract entry in the long run, and the price falls. In the long-run equilibrium, each firm produces 150 units, e, and 3,600 units are sold by the market, E2, by 24 (= 3,600/150) firms. Thus, with the D2 demand curve, price falls and output rises in the long run. Zero Long-Run Profit with Free Entry The long-run supply curve is horizontal if firms are free to enter the market, firms have identical cost, and input prices are constant. All firms in the market are operating at minimum long-run average cost. That is, they are indifferent between shutting down or not because they are earning zero economic profit. In a competitive market with identical firms and free entry, if most firms are profit-maximizing, profits are driven to zero at the long-run equilibrium. Any firm that does not maximize profit—that is, any firm that sets its output so that the market price does not equal its marginal cost or does not use the most cost-efficient methods of production—loses money. Thus, to survive in a competitive market in the long run, a firm must maximize its profit. 8.4 Competition Maximizes Economic Well-Being Why do we study competition in a book on managerial economics? There are two main reasons. First, many sectors of the economy are highly competitive including agriculture, parts of the construction industry, many labor markets, and much retail and wholesale trade. Second, and perhaps more important, perfect competition serves as an ideal or benchmark for other industries. This benchmark is widely used by economists and widely misused by politicians. Most U.S. politicians have at one point or another in their careers stated (with a hand over their heart), “I believe in the free market.” While we’re not about to bash free markets, we find this statement to be, at best, mysterious. What do the politicians mean by “believe in” and “free market?” Hopefully they realize that whether a free market is desirable is a scientific question rather than one of belief. Possibly when they say they “believe in,” they are making some claim that free markets are desirable for some unspecified reason. By “free market,” they might mean a market without government regulation or intervention. We believe that this statement is a bad summary of what is probably the most important theoretical result in economics: a perfectly competitive market maximizes an important measure of economic well-being. Adam Smith, the father of modern economics, in his book An Inquiry into the Nature and Causes of the Wealth of Nations in 1776, was 11How do we know which firms leave? If the firms are identical, the theory says nothing about which ones leave and which ones stay. The firms that leave make zero economic profit, and those that stay make zero economic profit, so firms are indifferent as to whether they stay or exit. 8.4 Competition Maximizes Economic Well-Being 255 the first to observe that firms and consumers acting independently in their own self interest generate a desirable outcome. This insight is sometimes called the invisible hand theorem.12 Because a competitive market is desirable, government intervention in a perfectly competitive market reduces a society’s economic well-being. However, government intervention may increase economic well-being in markets that are not perfectly competitive, such as in a monopolized market. In other words, freedom from government intervention does not guarantee that society’s well-being is maximized in markets that are not perfectly competitive. In the rest of this section, we first describe widely accepted measures of consumer well-being, consumer surplus, and producer well-being, producer surplus (a concept close to that of profit). Next, we define a measure of a society’s economic well-being, total surplus, as the sum of the consumer and producer measures of well-being. Then, we demonstrate why perfect competition maximizes total surplus. Finally, we discuss why a government action that causes a deviation from the perfectly competitive equilibrium reduces total surplus. Consumer Surplus The monetary difference between what a consumer is willing to pay for the quantity of the good purchased and what the consumer actually pays is called consumer surplus (CS). Consumer surplus is a dollar-value measure of the extra economic benefit the consumer receives from a transaction over and above the good’s price. By measuring how much more a consumer is willing to pay than the consumer actually paid, we know how much the consumer gained from this transaction. For example, if Jane is willing to pay up to $500 for a ticket to a U2 concert, but only has to pay $150, her consumer surplus is $350. We use this monetary measure to answer questions such as “What effect does a price increase have on consumers’ well-being?” or “How much does a government quota on the number of items each consumer may buy hurt consumers?” or “What is the harm to consumers from one firm monopolizing a market?”13 Measuring Consumer Surplus Using a Demand Curve. Because consumer surplus is the difference between what a consumer is willing to pay for a unit of a good and the price of that good, it is a measure of what the consumer gains from trade: from exchanging money for the good. We can use the information stored in a demand curve and the market price to determine consumer surplus. The 12The term invisible hand was coined by Smith. He expressed the basic theorem as “. . . every individual . . . intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value, he intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention. . . . By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it.” 13If we knew a consumer’s utility function (Chapter 4), we could directly answer the question of how an economic event, such as a price change, affects a consumer’s well-being. However, we do not know individual utility functions. Even if we did, we could not compare the utility levels of different individuals. If Mei says that she got 1,000 utils (units of utility) from watching a movie, while Alan reports that he got 872 utils, we would not know if Mei enjoyed the movie more than Alan. She might just be using a different subjective scale. Because of these and other difficulties in comparing consumers’ utilities, we use a monetary measure. CHAPTER 8 256 Competitive Firms and Markets demand curve reflects a consumer’s marginal willingness to pay: the maximum amount a consumer will spend for an extra unit. The consumer’s marginal willingness to pay is the marginal value the consumer places on the last unit of output. For example, David’s demand curve for magazines per week, panel a of Figure 8.9, indicates his marginal willingness to buy various numbers of magazines. David places a marginal value of $5 on the first magazine. As a result, if the price of a magazine is $5, David buys one magazine, point a on the demand curve. His marginal willingness to buy a second magazine is $4, so if the price falls to $4, he buys two magazines, b. His marginal willingness to buy three magazines is $3, so if the price of magazines is $3, he buys three magazines, c. David’s consumer surplus from each additional magazine is his marginal willingness to pay minus what he pays to obtain the magazine. His marginal willingness to pay for the first magazine, $5, is area CS1 + E1. If the price is $3, his expenditure to obtain the magazine is area E1 = $3. Thus, his consumer surplus on the first magazine is area CS1 = (CS1 + E1) - E1 = $5 - $3 = $2. Because his marginal willingness to pay for the second magazine is $4, his consumer surplus for the second magazine is the smaller area CS2 = $1. His marginal willingness to pay for the third magazine is $3, which equals what he must pay to obtain it, so his consumer surplus is zero, CS3 = $0. He is indifferent between buying and not buying the third magazine. F IG U RE 8. 9 Consumer Surplus (a) David’s demand curve for magazines has a step-like shape. When the price is $3, he buys three magazines, point c. David’s marginal value for the first magazine is $5, areas CS1 + E1, and his expenditure is $3, area E1, so his consumer surplus is CS1 = $2. His consumer surplus is $1 for the second magazine, area CS2, and is $0 for the third (he is indifferent between buying (b) Steven’s Consumer Surplus p, $ per trading card p, $ per magazine (a) David’s Consumer Surplus a 5 b 4 and not buying it). Thus, his total consumer surplus is the shaded area CS1 + CS2 + CS3 = $3. (b) Steven’s willingness to pay for trading cards is the height of his smooth demand curve. At price p1, Steven’s expenditure is E (= p1q1), his consumer surplus is CS, and the total value he places on consuming q1 trading cards per year is CS + E. CS1 = $2 CS2 = $1 c 3 Price = $3 Consumer surplus, CS 2 p1 E1 = $3 E2 = $3 E3 = $3 Demand Demand Expenditure, E 1 Marginal willingness to pay for the last unit of output 0 1 2 3 4 5 q, Magazines per week q1 q, Trading cards per year 8.4 Competition Maximizes Economic Well-Being 257 At a price of $3, David buys three magazines. His total consumer surplus from the three magazines he buys is the sum of the consumer surplus he gets from each of these magazines: CS1 + CS2 + CS3 = $2 + $1 + $0 = $3. This total consumer surplus of $3 is the extra amount that David is willing to spend for the right to buy three magazines at $3 each. Thus, an individual’s consumer surplus is the area under the demand curve and above the market price up to the quantity the consumer buys. David is unwilling to buy a fourth magazine unless the price drops to $2 or less. If David’s mother gives him a fourth magazine as a gift, the marginal value that David puts on that fourth magazine, $2, is less than what it cost his mother, $3. We can determine consumer surplus for smooth demand curves in the same way as with David’s unusual stair-like demand curve. Steven has a smooth demand curve for baseball trading cards, panel b of Figure 8.9. The height of this demand curve measures his willingness to pay for one more card. This willingness varies with the number of cards he buys in a year. The total value he places on obtaining q1 cards per year is the area under the demand curve up to q1, the areas CS and E. Area E is his actual expenditure on q1 cards. Because the price is p1, his expenditure is p1q1. Steven’s consumer surplus from consuming q1 trading cards is the value of consuming those cards, areas CS and E, minus his actual expenditures E to obtain them, or CS. Thus, his consumer surplus, CS, is the area under the demand curve and above the horizontal line at the price p1 up to the quantity he buys, q1. Just as we measure the consumer surplus for an individual using that individual’s demand curve, we measure the consumer surplus of all consumers in a market using the market demand curve. Market consumer surplus is the area under the market demand curve above the market price up to the quantity consumers buy. To summarize, consumer surplus is a practical and convenient measure of consumers’ economic benefits from market transactions. There are two advantages to using consumer surplus rather than utility to discuss economic benefits. First, the dollar-denominated consumer surplus of several individuals can be easily compared or combined, whereas the utility of various individuals cannot be easily compared or combined. Second, it is relatively easy to measure consumer surplus, whereas it is difficult to get a meaningful measure of utility directly. To calculate consumer surplus, all we have to do is measure the area under a demand curve. Ma nagerial I mplication Willingness to Pay on eBay If a product is sold on eBay, a manager can use the information that eBay reports to quickly estimate the market demand curve for the product. People differ in their willingness to pay for a given item. We can determine individuals’ willingness to pay for a 238 a.d. Roman coin, a sesterce (originally equivalent in value to two and a half asses) of Emperor Balbinus, by how much they bid in an eBay auction. On its website, eBay correctly argues (Chapter 12) that the best strategy for bidders is to bid their willingness to pay: the maximum value that they place on the item. If bidders follow this strategy, from what eBay reports, we know the maximum bid of each person except the winner because eBay uses a second-price auction, where the winner pays the second-highest amount bid (plus an CHAPTER 8 Competitive Firms and Markets increment).14 In the figure, bids are arranged from highest to lowest. Because each bar on the graph indicates the bid for one coin, the figure shows how many units could have been sold to this group of bidders at various prices (assuming each bidder wants only one coin). That is, it is the market demand curve. Willingness to pay, $ bid per coin 258 $? $1,003 $950 $706 $600 $555 $166 $108 $50 1 2 3 4 5 6 7 8 $28 9 10 Q, Number of coins Effects of a Price Change on Consumer Surplus. If the supply curve shifts upward or a government imposes a new sales tax, the equilibrium price rises, causing the consumer surplus to fall. We illustrate the effect of a price increase on market consumer surplus using estimated supply and demand curves for sweetheart and hybrid tea roses sold in the United States.15 We then discuss which markets are likely to have the greatest loss of consumer surplus due to a price increase. Suppose that the introduction of a new tax causes the wholesale price of roses to rise from the original equilibrium price of 30¢ to 32¢ per rose stem, a movement along the demand curve in Figure 8.10. The consumer surplus at the initial price of 30¢ is area A + B + C = $173.74 million per year.16 At a higher price of 32¢, the consumer surplus falls to area A = $149.64 million. Thus, the loss in consumer surplus from the increase in price is B + C = $24.1 million per year. Producer Surplus A supplier’s gain from participating in the market is measured by producer surplus (PS), which is the difference between the amount a good sells for and the minimum amount necessary for the producers to be willing to produce the good. 14The increment depends on the size of the bid. It is $1 for bids between $25 and $100 and $25 for bids between $1,000 and $2,499.99. 15We estimated this model using data from the Statistical Abstract of United States, Floriculture Crops, Floriculture and Environmental Horticulture Products, and usda.mannlib.cornell.edu. The prices are in real 1991 dollars. height of triangle A is 25.8¢ = 57.8¢ - 32¢ per stem and the base is 1.16 billion stems per year, so its area is 12 * $0.258 * 1.16 billion = $149.64 million per year. Rectangle B is $0.02 * 1.16 billion = $23.2 million. Triangle C is 12 * $0.02 * 0.09 billion = $0.9 million. 16The 8.4 Competition Maximizes Economic Well-Being 259 As the price of roses rises 2¢ per stem from 30¢ to 32¢ per stem, the quantity demanded decreases from 1.25 to 1.16 billion stems per year. The loss in consumer surplus from the higher price, areas B and C, is $24.1 million per year. p, ¢ per stem F IG U RE 8. 10 Fall in Consumer Surplus from Roses as Price Rises 57.8 A = $149.64 million 32 30 b B = $23.2 million C = $0.9 million a Demand 0 1.16 1.25 Q, Billion rose stems per year The minimum amount a firm must receive to be willing to produce is the firm’s avoidable production cost. Therefore, producer surplus is a measure of what the firm gains from trade. Measuring Producer Surplus Using a Supply Curve. To determine a competitive firm’s producer surplus, we use its supply curve: its marginal cost curve above its minimum average variable cost. The firm’s supply curve in panel a of Figure 8.11 looks like a staircase. The marginal cost of producing the first unit is MC1 = $1, which is the area under the marginal cost curve between 0 and 1. The marginal cost of producing the second unit is MC2 = $2, and so on. The variable cost, VC, of producing four units is the sum of the marginal costs for the first four units: VC = MC1 + MC2 + MC3 + MC4 = $1 + $2 + $3 + $4 = $10. If the market price, p, is $4, the firm’s revenue from the sale of the first unit exceeds its cost by PS1 = p - MC1 = $4 - $1 = $3, which is its producer surplus on the first unit. The firm’s producer surplus is $2 on the second unit and $1 on the third unit. On the fourth unit, the price equals marginal cost, so the firm just breaks even. As a result, the firm’s total producer surplus, PS, from selling four units at $4 each is the sum of its producer surplus on these four units: PS = PS1 + PS2 + PS3 + PS4 = $3 + $2 + $1 + $0 = $6. Graphically, the total producer surplus is the area above the supply curve and below the market price up to the quantity actually produced. This same reasoning holds when the firm’s supply curve is smooth. A firm’s producer surplus is revenue, R, minus variable cost, VC: PS = R - VC. In panel a of Figure 8.11, revenue is $4 * 4 = $16 and variable cost is $10, so the firm’s producer surplus is $6. 260 CHAPTER 8 Competitive Firms and Markets F IG U RE 8. 11 Producer Surplus (a) The firm’s producer surplus, $6, is the area below the market price, $4, and above the marginal cost (supply curve) up to the quantity sold, 4. The area under the marginal cost curve up to the number of units actually produced is the variable cost of production. (b) The market (b) A Market’s Producer Surplus Supply 4 p PS1 = $3 PS2 = $2 PS3 = $1 3 p, Price per unit p, $ per unit (a) A Firm’s Producer Surplus producer surplus is the area above the supply curve and below the line at the market price, p*, up to the quantity produced, Q*. The area below the supply curve and to the left of the quantity produced by the market, Q*, is the variable cost of producing that level of output. Market supply curve p* Market price Producer surplus, PS 2 1 MC1 = $1 MC2 = $2 MC3 = $3 MC4 = $4 0 1 2 3 Variable cost, VC 4 q, Units per week Q& A 8.2 Q* Q, Units per year If a firm has unavoidable fixed costs of F, how is its producer surplus related to its profit? Answer 1. Express the formula for profit in terms of variable and fixed cost. A firm’s profit is its revenue minus its total cost, C, which equals variable cost plus fixed cost, F: π = R - C = R - (VC + F). 2. Take the difference between producer surplus and profit. The difference is PS - π = (R - VC) - (R - VC - F) = F. Thus, the difference between a firm’s producer surplus and profit is the fixed cost, F. If the fixed cost is zero (as often occurs in the long run), producer surplus equals profit. Using Producer Surplus. Even in the short run, we can use producer surplus to study the effects of a shock that affects the variable cost of production, such as a change in the price of a substitute or a variable input. Such shocks change profit by exactly the same amount as they change producer surplus because fixed costs do not change. 8.4 Competition Maximizes Economic Well-Being 261 A major advantage of producer surplus is that we can use it to measure the effect of a shock on all the firms in a market without having to measure the profit of each firm in the market separately. We can calculate market producer surplus using the market supply curve in the same way as we calculate a firm’s producer surplus using its supply curve. The market producer surplus in panel b of Figure 8.11 is the area above the supply curve and below the market price, p*, up to the quantity sold, Q*. The market supply curve is the horizontal sum of the marginal cost curves of each of the firms. As a result, the variable cost for all the firms in the market of producing Q is the area under the supply curve between 0 and the market output, Q*. We estimated the supply curve for roses, which is the upward-sloping line in the following figure. How much producer surplus is lost if the price of roses falls from 30¢ to 21¢ per stem (so that the quantity sold falls from 1.25 billion to 1.16 billion rose stems per year)? Answer 1. Draw the supply curve, and show the change in producer surplus caused by the price change. The figure shows the estimated supply curve for roses. Point a indicates the quantity supplied at the original price, 30¢, and point b reflects the quantity supplied at the lower price, 21¢. The loss in producer surplus is the sum of rectangle D and triangle E. p, ¢ per stem Q& A 8.3 Supply 30 D = $104.4 million 21 E = $4.05 million a b F 0 1.16 1.25 Q, Billion rose stems per year Producer Surplus Original Price, 30¢ Lower Price, 21¢ Change ($ millions) D+E+F F –(D + E) = –108.45 2. Calculate the lost producer surplus by adding the areas of rectangle D and triangle E. The height of rectangle D is the difference between the original and the new price, 9¢, and its base is 1.16 billion stems per year, so the area of D (not all of which is shown in the figure because of the break in the quantity axis) is $0.09 262 CHAPTER 8 Competitive Firms and Markets per stem × 1.16 billion stems per year = $104.4 million per year. The height of triangle E is also 9¢, and its length is 90 million stems per year, so its area is 1 2 * $0.09 per stem × 90 million stems per year = $4.05 million per year. Thus, the loss in producer surplus from the drop in price is $108.45 million per year. Competition Maximizes Total Surplus One of the most important results in economics is that perfect competition maximizes the sum of consumer surplus and producer surplus, which we call total surplus (TS):17 TS = CS + PS. Total surplus is a measure of the total benefit to all market participants from market transactions, which are market participants’ gains from trade. Total surplus implicitly weights the gains to consumers and producers equally. By using this measure to assess policies that affect market transactions, we are making a value judgment that the well-being of consumers and that of producers are equally important. While most economists and many other people accept total surplus as a reasonable objective for society to try to maximize, not everyone agrees. Groups of producers commonly argue for legislation that helps them even if it hurts consumers by more than the producers gain—as though only producer surplus matters. Similarly, some consumer advocates argue that we should care only about consumers, so social well-being should include only consumer surplus. A demonstration that perfect competition maximizes total surplus requires showing that (1) producing less than the competitive output lowers economic benefit as measured by total surplus, and (2) producing more than the competitive output lowers total surplus. We show that reducing output from the competitive level reduces consumer surplus, producer surplus, and total surplus. (In Question 4.3 at the end of the chapter, you are asked to use a similar analysis to show that producing more than the competitive equilibrium quantity reduces total surplus.) At the competitive equilibrium in Figure 8.12, E1, where output is Q1 and price is p1, consumer surplus, CS1, equals areas A + B + C, producer surplus, PS1, is D + E, and the total surplus is TS1 = A + B + C + D + E. Now suppose that we reduce output slightly from the competitive equilibrium quantity Q1 to Q2. As a result, price rises to p2 at e2, consumer surplus falls to CS2 = A, producer surplus drops to PS2 = B + D, and total surplus falls to TS2 = A + B + D. The change in consumer surplus is ΔCS = CS2 - CS1 = A - (A + B + C) = -B - C. Consumers lose B because they have to pay p2 - p1 more than at the competitive price for the Q2 units they buy. Consumers lose C because they buy only Q2 rather than Q1 at the higher price. 17Many economists call this sum welfare. We do not use that term because it has many different meanings in common speech. 8.4 Competition Maximizes Economic Well-Being 263 F IG U RE 8. 12 Reducing Output from the Competitive Level Lowers Total Surplus gain or lose: Producer surplus is now B + D, a change of ΔPS = B - E. Overall, total surplus falls by ΔTS = -C - E, which is a deadweight loss (DWL) to society. p, $ per unit Reducing output from the competitive level, Q1, to Q2 causes price to increase from p1 to p2. Consumers suffer: Consumer surplus is now A, a fall of ΔCS = - B - C. Producers may Supply A e2 p2 B e1 C MC1 = p1 E D Demand MC2 F Q2 Consumer Surplus, CS Producer Surplus, PS Total Surplus, TS = CS + PS Q1 Q, Units per year Competitive Output, Q1 (1) Smaller Output, Q2 (2) A+B+C D+E A B+D −B − C = ΔCS B − E = ΔPS A+B+C+D+E A+B+D −C − E = ΔTS = DWL Change (2) – (1) The change in producer surplus is ΔPS = PS2 - PS1 = (B + D) - (D + E) = B - E. Producers gain B because they now sell Q2 units at p2 rather than p1. They lose E because they sell Q2 - Q1 fewer units. The change in total surplus, ΔTS = TS2 - TS1, is18 ΔTS = ΔCS + ΔPS = (-B - C) + (B - E) = -C - E. The area B is a transfer from consumers to producers—the extra amount consumers pay for the Q2 units goes to the sellers—so it does not affect total surplus. Total surplus drops because the consumer loss of C and the producer change in total surplus is ΔTS = TS2 - TS1 = (CS2 + PS2) - (CS1 + PS1) = (CS2 - CS1) + (PS2 - PS1) = ΔCS + ΔPS. 18The 264 CHAPTER 8 Competitive Firms and Markets loss of E benefit no one. This drop in total surplus, ΔTS = -C - E, is a deadweight loss (DWL): the net reduction in total surplus from a loss of surplus by one group that is not offset by a gain to another group from an action that alters a market equilibrium. The deadweight loss results because consumers value extra output by more than the marginal cost of producing it. At each output between Q2 and Q1, consumers’ marginal willingness to pay for another unit—the height of the demand curve—is greater than the marginal cost of producing the next unit—the height of the supply curve. For example, at e2, consumers value the next unit of output at p2, which is much greater than the marginal cost, MC2, of producing it. Increasing output from Q2 to Q1 raises firms’ variable cost by area F, the area under the marginal cost (supply) curve between Q2 and Q1. Consumers value this extra output by the area under the demand curve between Q2 and Q1, area C + E + F. Thus, consumers value the extra output by C + E more than it costs to produce it. Society would be better off producing and consuming extra units of this good than spending this amount on other goods. In short, the deadweight loss is the opportunity cost of giving up some of this good to buy more of another good. M ini-Case The Deadweight Loss of Christmas Presents Just how much did Nicholas enjoy the expensive lime green woolen socks with the dancing purple teddy bears that his Aunt Fern gave him last Christmas? Often the cost of a gift exceeds the value that the recipient places on it. Until the advent of gift cards, only 10% to 15% of holiday gifts were monetary. A gift of cash typically gives at least as much pleasure to the recipient as a gift that costs the same but can’t be exchanged for cash. (So what if giving cash is tacky?) Of course, it’s possible that a gift can give more pleasure to the recipient than it cost the giver—but how often does that happen to you? An efficient gift is one that the recipient values as much as the gift costs the giver, or more. The difference between the price of the gift and its value to the recipient is a deadweight loss to society. Joel Waldfogel (1993, 2009) asked Yale undergraduates just how large this deadweight loss is. He estimated that the deadweight loss is between 10% and 33% of the value of gifts. Waldfogel (2005) found that consumers value their own purchases at 10% to 18% more, 8.4 Competition Maximizes Economic Well-Being 265 per dollar spent, than items received as gifts.19 Indeed, only 65% of holiday shoppers said they didn’t return a single gift after Christmas 2010. Waldfogel found that gifts from friends and “significant others” are most efficient, while noncash gifts from members of the extended family are least efficient (one-third of the value is lost).20 Luckily, grandparents, aunts, and uncles are most likely to give cash. Given holiday expenditures of about $66 billion in 2007 in the United States, Waldfogel concluded that a conservative estimate of the deadweight loss of Christmas, Hanukkah, and other holidays with gift-giving rituals is about $12 billion. (And that’s not counting about 2.8 billion hours spent shopping.) The question remains why people don’t give cash instead of presents. Indeed, 61% of Americans gave a gift card as a Christmas present. (A gift card is the equivalent of cash, though some can only be used in a particular store.) More than $110 billion in gift cards were purchased in 2012 in the United States. If the reason others don’t give cash or gift cards is that they get pleasure from picking the “perfect” gift, the deadweight loss that adjusts for the pleasure of the giver is lower than these calculations suggest. (Bah, humbug!) Effects of Government Intervention I don’t make jokes. I just watch the government and report the facts. —Will Rogers A government policy that limits trade in a competitive market reduces total surplus. For example, in some markets the government imposes a price ceiling, which sets a limit on the highest price that a firm can legally charge. If the government sets the ceiling below the precontrol competitive price, consumers want to buy more than the precontrol equilibrium quantity but firms supply less than that quantity. (For example, see Chapter 2’s Mini-Case “Disastrous Price Controls.”) Thus, due to the price ceiling, consumers can buy the good at a lower price but cannot buy as much of it as they’d like. Because less is sold than at the precontrol equilibrium, there is deadweight loss: Consumers value the good more than the marginal cost of producing extra units. Producer surplus must fall because firms receive a lower price and sell fewer units. 19Gift recipients may exhibit an endowment effect (Chapter 4), in which their willingness to pay (WTP) for the gift is less than what they would have to be offered to give up the gift, their willingness to accept (WTA). Bauer and Schmidt (2008) asked students at the Ruhr University in Germany their WTP and WTA for three recently received Christmas gifts. On average over all students and gifts, the average WTP was 11% percent below the market price and the WTA was 18% above the market price. 20People may deal with a disappointing present by “regifting” it. Some families have been passing the same fruitcake among family members for decades. According to one survey, 33% of women and 19% of men admitted that they pass on an unwanted gift (and 28% of respondents said that they would not admit it if asked whether they had done so). 266 CHAPTER 8 Competitive Firms and Markets What is the effect on the equilibrium and consumer, producer, and total surplus if the government sets a price ceiling, p, below the unregulated competitive equilibrium price? Q& A 8.4 Answer p, $ per unit 1. Show the initial unregulated equilibrium. The intersection of the demand curve and the supply curve determines the unregulated, competitive equilibrium e1, where the equilibrium quantity is Q1. A p3 p1 Supply B C D E p2 F e1 – p, Price ceiling e2 Demand Q s = Q2 Q1 Qd Q, Units per year Consumer Surplus, CS Producer Surplus, PS Total Surplus, TS = CS + PS No Ceiling Price Ceiling Change A+B+C D+E+F A+B+D F D − C = ΔCS −D − E = ΔPS A+B+C+D+E+F A+B+D+F −C − E = ΔTS = DWL 2. Show how the equilibrium changes with the price ceiling. Because the price ceiling, p, is set below the equilibrium price of p1, the ceiling binds. At this lower price, consumer demand increases to Qd while the quantity firms are willing to supply falls to Qs, so only Qs = Q2 units are sold at the new equilibrium, e2. Thus, the price control causes the equilibrium quantity and price to fall, but consumers have excess demand of Qd - Qs. 3. Describe the effects on consumer, producer, and total surplus. Because consumers are able to buy Qs units at a lower price than before the controls, they gain area D. Consumers lose consumer surplus of C, however, because they can purchase only Qs instead of Q1 units of output. Thus, consumers gain net consumer surplus of D - C. Because they sell fewer units at a lower price, firms lose producer surplus -D - E. Part of this loss, D, is transferred to consumers because of lower prices, but the rest, E, is a loss to society. The deadweight loss to society is at least ΔTS = ΔCS + ΔPS = -C - E. Comment: This measure of the deadweight loss may underestimate the true loss. Because consumers want to buy more units than are sold, they may spend time 8.4 Competition Maximizes Economic Well-Being 267 searching for a store that has units for sale. This unsuccessful search activity is wasteful and hence a deadweight loss to society. (Note that less of this wasteful search does not occur if the good is known to be efficiently but inequitably distributed to people according to some discriminatory criterion such as race, gender, being in the military, or being attractive.) Another possible inefficiency is that consumers who buy the good may value it less than those who are unable to find a unit to purchase. For example, someone might purchase the good who values it at p 2 , while someone who values it at p3 cannot find any to buy. We return to the Managerial Problems at the beginning of the chapter about the effects of higher annual fees and other lump-sum costs on the trucking market price and quantity, the output of individual firms, and the number of trucking firms (assuming that the demand curve remains constant). Because firms may enter and exit this industry in the long run, such higher lump-sum costs can have a counterintuitive effect on the competitive equilibrium. All trucks of a certain size are essentially identical, and trucks can easily enter and exit the industry (government regulations aside). Panel a of the figure shows a typical firm’s cost curves and panel b shows the market equilibrium. Ma nagerial So l ution The Rising Cost of Keeping On Truckin’ (b) Market MC 2 1 AC = AC + T/q p, $ per unit p, $ per unit (a) Firm AC1 e2 p2 p2 e1 p1 p1 E2 S2 E1 S1 D q1 q2 q, Units per year Q2 = n2q2 Q1 = n1q1 Q, Units per year The new, higher fees and other lump-sum costs raise the fixed cost of operating by T. In panel a, a lump-sum, franchise tax shifts the typical firm’s average cost curve upward from AC 1 to AC 2 = AC 1 + T/q, but does not affect the marginal cost. As a result, the minimum average cost rises from e1 to e2. Given that an unlimited number of identical truckers are willing to operate in this market, the long-run market supply is horizontal at minimum average cost. Thus, the market supply curve shifts upward in panel b by the same amount as the minimum average cost increases. Given a downward-sloping market 268 CHAPTER 8 Competitive Firms and Markets demand curve D, the new equilibrium, E2, has a lower quantity, Q2 6 Q1, and higher price, p2 7 p1, than the original equilibrium, E1. As the market price rises, the quantity that a firm produces rises from q1 to q2 in panel a. Because the marginal cost curve is upward sloping at the original equilibrium, when the average cost curve shifts up due to the higher fixed cost, the new minimum point on the average cost curve corresponds to a larger output than in the original equilibrium. Thus, any trucking firm still operating in the market produces at a larger volume. Because the market quantity falls but each firm remaining in the market produces more, the number of firms in the market must fall. At the initial equilibrium, the number of firms was n1 = Q1/q1. The new equilibrium number of firms, n2 = Q2/q2, must be smaller than n1 because Q2 6 Q1 and q2 7 q1. Therefore, an increase in fixed cost causes the market price to rise and the total quantity and number of trucking firms to fall, as most people would have expected. However, it also has the surprising effect that it causes output per firm to increase for the firms that continue to produce. S U MMARY 1. Perfect Competition. Perfect competition is a market structure in which buyers and sellers are price takers. Each firm faces a horizontal demand curve. A firm’s demand curve is horizontal because perfectly competitive markets have five characteristics: there are a very large number of small buyers and sellers, firms produce identical (homogeneous) products, buyers have full information about product prices and characteristics, transaction costs are negligible, and there is free entry and exit in the long run. Many markets are highly competitive—firms are very close to being price takers—even if they do not strictly possess all five of the characteristics associated with perfect competition. 2. Competition in the Short Run. To maximize its profit, a competitive firm (like a firm in any other market structure) chooses its output level where marginal revenue equals marginal cost. Because a competitive firm is a price taker, its marginal revenue equals the market price, so it sets its output so that price equals marginal cost. New firms cannot enter in the short run. In addition, firms that are in the industry have some fixed inputs that cannot be changed and whose costs cannot be avoided. In this sense firms cannot exit the industry in the short run. However, a profit-maximizing firm shuts down and produces no output if the market price is less than its minimum average variable cost. Thus, a competitive firm’s short-run supply curve is its marginal cost curve above its minimum average variable cost. The short-run market supply curve is the sum of the supply curves of the fixed number of firms producing in the short run. The short-run competitive equilibrium is determined by the intersection of the market demand curve and the short-run market supply curve. 3. Competition in the Long Run. In the long run, a competitive firm sets its output where the market price equals its long-run marginal cost. It shuts down if the market price is less than the minimum of its long-run average cost, because all costs are avoidable in the long run. Consequently, the competitive firm’s long-run supply curve is its long-run marginal cost above its minimum long-run average cost. The long-run supply curve of a firm may have a different slope than the shortrun curve because it can vary its fixed inputs in the long run. The long-run market supply curve is the horizontal sum of the supply curves of all the firms in the market. If all firms are identical, entry and exit are easy, and input prices are constant, then the long-run market supply curve is flat at minimum average cost. If firms differ, entry is difficult or costly, or input prices increase with output, the long-run market supply curve has an upward slope. The long-run market equilibrium price and quantity may be different from the short-run price and quantity. 4. Competition Maximizes Economic Well-Being. Perfect competition maximizes a commonly used measure of economic well-being, total surplus. Total surplus is the monetary value of the gain from trade. It is the sum of consumer surplus and producer surplus. Consumer surplus Questions is the economic benefit or well-being obtained by a consumer in excess of the price paid. It equals the area under the consumer’s demand curve above the market price up to the quantity that the consumer buys. Producer surplus is the amount producers are paid over and above the minimum amount needed to induce them to produce a given output level. A firm’s producer surplus is 269 its revenue minus the variable cost of production. Thus, if a firm has no fixed costs, as often occurs in the long run, a firm’s producer surplus is the same as profit. In the short run, a firm’s producer surplus is greater than profit by an amount equal to unavoidable fixed cost. Producer surplus is the area below the price and above the supply curve up to the quantity that the firm sells. Q U E S T ION S All exercises are available on MyEconLab; * = answer at the back of this book; C = use of calculus may be necessary. 1. Perfect Competition 1.1. A large city has nearly 500 restaurants, with new ones entering regularly as the population grows. The city decides to limit the number of restaurant licenses to 500. Which characteristics of this market are consistent with perfect competition and which are not? Is this restaurant market likely to be nearly perfectly competitive? Why? *1.2. Why would high transaction costs or imperfect information tend to prevent price-taking behavior? 2. Competition in the Short Run 2.1. Mercedes-Benz of San Francisco advertises on the radio that it has been owned and operated by the same family in the same location for 50 years (as of 2012). It then makes two claims: first, that it has lower overhead than other nearby auto dealers because it has owned this land for 50 years, and second, it charges a lower price for its cars because of its lower overhead. Discuss the logic of these claims. *2.2. Many marginal cost curves are U-shaped. As a result, it is possible that the MC curve hits the demand or price line at two output levels. Which is the profit-maximizing output? Why? 2.3. Initially, the market price was p = 20, and the competitive firm’s minimum average variable cost was 18, while its minimum average cost was 21. Should it shut down? Why? Now this firm’s average variable cost increases by 3 at every quantity, while other firms in the market are unaffected. What happens to its average cost? Should this firm shut down? Why? 2.4. Should a firm shut down if its revenue is R = $1,000 per week, a. its variable cost is VC = $500, and its sunk fixed cost is F = $600? b. its variable cost is VC = $1,001, and its sunk fixed cost F = $500? c. its variable cost is VC = $500, and its fixed cost is $800, of which $600 is avoidable if it shuts down? *2.5. The cost function for Acme Laundry is C(q) = 10 + 10q + q2, so its marginal cost function is MC = 10 + 2q, where q is tons of laundry cleaned. Derive the firm’s average cost and average variable cost curves. What q should the firm choose so as to maximize its profit if the market price is p? How much does it produce if the competitive market price is p = 50? 2.6. Beta Laundry’s cost function is C(q) = 30 + 20q + q2. a. What quantity maximizes the firm’s profit if the market price is p? How much does it produce if p = 60? b. If the government imposes a specific tax of t = 2, what quantity maximizes its after-tax profit? Does it operate or shut down? (Hint: See Q&A 8.1.) C 2.7. If the pre-tax cost function for John’s Shoe Repair is C(q) = 100 + 10q - q2 + 13 q3, and it faces a specific tax of t = 10, what is its profit-maximizing condition if the market price is p? Can you solve for a single, profit-maximizing q in terms of p? (Hint: See Q&A 8.1.) C 2.8. If a specific subsidy (negative tax) of s is given to only one competitive firm, how should that firm change its output level to maximize its profit, and how does its maximum profit change? Use a graph to illustrate your answer. (Hint: See Q&A 8.1.) 2.9. According to the “Oil, Oil Sands, and Oil Shale Shutdowns” Mini-Case, the minimum average variable cost of processing oil sands dropped from $25 a barrel in the 1960s to $18 due to technological advances. In a figure, show how this change affects the supply curve of a typical competitive firm and the supply curve of all the firms producing oil from oil sands. 2.10. Fierce storms in October 2004 caused TomatoFest Organic Heirlooms Farm to end its tomato harvest two weeks early. According to Gary Ibsen, a partner in this small business (Carolyn Said, “Tomatoes in 270 CHAPTER 8 Competitive Firms and Markets Trouble,” San Francisco Chronicle, October 29, 2004, C1, C2), TomatoFest lost about 20,000 pounds of tomatoes that would have sold for about $38,000; however, because he did not have to hire pickers and rent trucks during these two weeks, his net loss was about $20,000. In calculating the revenue loss, he used the post-storm price, which was double the pre-storm price. a. Draw a diagram for a typical firm next to one for the market to show what happened as a result of the storm. Assume that TomatoFest’s experience was typical of that of many small tomato farms. b. Did TomatoFest suffer an economic loss? What extra information (if any) do you need to answer this question? How do you define “economic loss” in this situation? 2.11. The Internet is affecting holiday shipping. In years past, the busiest shipping period was Thanksgiving week. Now as people have become comfortable with e-commerce, they purchase later in the year and are more likely to have gifts shipped (rather than purchasing locally). FedEx, along with Amazon and other e-commerce firms, hires extra workers during this period, and many regular workers log substantial overtime hours. a. Are the marginal and average costs of Internet retailers likely to rise or fall with this extra business? (Discuss economies of scale and the slopes of marginal and average cost curves.) b. Use side-by-side firm-market diagrams to show the effects on the number of firms, equilibrium price and output, and profits of such a seasonal shift in demand for e-retailers in both the short run and the long run. Explain your reasoning. 2.12. What is the effect on the short-run equilibrium of a specific subsidy of s per unit that is given to all n firms in a market? 3. Competition in the Long Run 3.1. As of 2013, customers at California grocery and drug stores must pay an extra 10¢ for every paper bag that the store provides (the store keeps this fee). Does such a charge affect the marginal cost of any particular good? If so, by how much? Is this fee likely to affect the overall amount that consumers pay for groceries? *3.2. What is the short-run and long-run effect on firm and market equilibrium of the U.S. law requiring a firm to give its workers six months’ notice before it can shut down its plant? 3.3. The “Upward-Sloping Long-Run Supply Curve for Cotton” Mini-Case shows a supply curve for cotton. Discuss the equilibrium if the world demand curve crosses this supply curve in either (a) a flat section labeled Brazil or (b) the following vertical section. What do cotton farms in the United States do? 3.4. Chinese art factories are flooding the world’s generic art market (Keith Bradsher, “Own Original Chinese Copies of Real Western Art!” New York Times, July 15, 2005). The value of bulk shipments of Chinese paintings to the United States nearly tripled from slightly over $10 million in 1996 to $30.5 million in 2004 (and early 2005 sales were up 50% from the corresponding period in 2004). A typical artist earns less than $200 a month, plus modest room and board, or $360 a month without food and housing. Using a step-like supply function (similar to the one in the “Upward-Sloping Long-Run Supply Curve for Cotton” Mini-Case), show how the entry of the Chinese affects the world supply curve and how this change affects the equilibrium (including who produces art). Explain. 3.5. The 2010 oil spill in the Gulf of Mexico caused the oil firm BP and the U.S. government to greatly increase purchases of boat services, various oil-absorbing materials, and other goods and services to minimize damage from the spill. Use side-by-side firm and market diagrams to show the effects (number of firms, price, output, profits) of such a shift in demand in one such industry, such as boat services, in both the short run and the long run. Explain how your answer depends on whether the shift in demand is expected to be temporary or permanent. 3.6. In late 2004 and early 2005, the price of raw coffee beans jumped as much as 50% from the previous year. In response, the price of roasted coffee rose about 14%. Similarly, in 2012, the price of raw beans fell by a third, yet the price of roasted coffee fell by only a few percentage points. Why did the roasted coffee price change less than in proportion to the rise in the cost of raw beans? 3.7. In 2009, the voters of Oakland, California, passed a measure to tax medical cannabis (marijuana), effectively legalizing it. In 2010, the City Council adopted regulations permitting industrial-scale marijuana farms with no size limits but requiring each to pay a $211,000 per year fee.21 One proposal called for 21Matthai Kuruvila, “Oakland Allows Industrial-Scale Marijuana Farms,” San Francisco Chronicle, July 21, 2010, and Malia Wol- lan, “Oakland, Seeking Financial Lift, Approves Giant Marijuana Farms,” New York Times, July 21, 2010. Questions a 100,000 square feet farm, the size of two football fields. Prior to this legalization, only individuals could grow marijuana. These small farmers complained bitterly, arguing that the large firms would drive them out of the industry they helped to build due to economies of scale. Draw a figure to illustrate the situation. Under what conditions (such as relative costs, position of the demand curve, number of low-cost firms) will the smaller, higher-cost growers be driven out of business? (In 2012, the federal government brought an end to this business in Oakland. However, Colorado and Washington state passed laws permitting marijuana sales as of 2013.) 4. Competition Maximizes Economic Well-Being *4.1. If the inverse demand function for toasters is p = 60 - Q, what is the consumer surplus when the price is 30? 4.2. For a firm, how does the concept of producer surplus differ from that of profit if it has no fixed costs? (Hint: See Q&A 8.2.) *4.3. Using a graph similar to Figure 8.12, show that increasing output beyond the competitive level decreases total surplus because the cost of producing this extra output exceeds the value consumers place on it. 4.4. If the supply function is Q = 10 + p, what is the producer surplus if price is 20? (Hint: See Q&A 8.3.) 4.5. Use an indifference curve (Chapter 4) diagram (gift goods on one axis and all other goods on the other) to illustrate that a consumer is better off receiving cash rather than a gift. Relate your analysis to the Mini-Case “The Deadweight Loss of Christmas Presents.” 4.6. The government sets a minimum wage above the current equilibrium wage. What effect does the minimum wage have on the market equilibrium? What are its effects on consumer surplus, producer surplus, and total surplus? Who are the consumers and who are the producers? (Hint: See Q&A 8.4.) 271 5. Managerial Problem 5.1. The North American Free Trade Agreement provides for two-way, long-haul trucking across the U.S.-Mexican border. U.S. truckers have objected, arguing that the Mexican trucks don’t have to meet the same environmental and safety standards as U.S. trucks. They are concerned that the combination of these lower fixed costs and lower Mexican wages will result in Mexican drivers taking business from them. Their complaints have delayed implementation of this agreement (except for a small pilot program during the Bush administration, which was ended during the Obama administration). What would be the short-run and long-run effects of allowing entry of Mexican drivers on market price and quantity and on the number of U.S. truckers? 5.2. In the Managerial Solution, would it make a difference to the analysis whether the lump-sum costs such as registration fees are collected annually or only once when the firm starts operation? How would each of these franchise taxes affect the firm’s long-run supply curve? Explain your answer. 5.3. Give an answer to the Managerial Problem for the short run rather than for the long run. (Hint: The answer depends on where the demand curve intersects the original short-run supply curve.) 5.4. In a perfectly competitive market, all firms are identical, there is free entry and exit, and an unlimited number of potential entrants. Now, the government starts collecting a specific tax t. What is the effect on the long-run equilibrium market quantity, market price, and the quantity for an individual firm? 6. Spreadsheet Exercises 6.1. A competitive firm’s cost of producing q units of output is C = 18 + 4q + q2. Its corresponding marginal cost is MC = 2q + 4. a. Describe how the equilibrium changes. a. The firm faces a market price p = $24. Create a spreadsheet with q = 0, 1, 2, c , 15, where the columns are q, R, C, VC, AVC, MC, and profit. Determine the profit-maximizing output for the firm and the corresponding profit. Should the firm produce this level of output or should it shut down? Explain. b. What effect does this price ceiling have on consumer surplus, producer surplus, and deadweight loss? b. Suppose the competitive price declines to p = $12. Repeat the calculations of part a. Should the firm shut down? 4.7. Suppose that the demand curve for wheat is Q = 100 - 10p and the supply curve is Q = 10p. The government imposes a price ceiling of p = 3. (Hint: See Q&A 8.4.) 272 CHAPTER 8 Competitive Firms and Markets 6.2. In a competitive market, the market demand curve is Q = 28 - 2p and the market supply curve is Qs = -8 + 2p. Use a spreadsheet to answer the following questions. a. Determine the quantity demanded and quantity supplied for p = $4, 5, 6, c , 14. Determine the equilibrium quantity and price. b. For prices p = $4, 5, 6, c , 14, determine the consumer surplus. How does an increase in price affect the consumer surplus? c. For prices p = $4, 5, 6, c , 14, determine the producer surplus. How does an increase in price affect the producer surplus? d. Suppose the government limits the quantity traded in the market to 6 units. Calculate the resulting deadweight loss. Monopoly Monopoly: one parrot. Ma nagerial P ro blem Brand-Name and Generic Drugs 9 A firm that creates a new drug may receive a patent that gives it the right to be the monopoly or sole producer of the drug for up to 20 years. As a result, the firm can charge a price much greater than its marginal cost of production. For example, one of the world’s best-selling drugs, the heart medication Plavix, sold for about $7 per pill but can be produced for about 3¢ per pill. Prices for drugs used to treat rare diseases are often very high. Drugs used for certain rare types of anemia cost patients about $5,000 per year. As high as this price is, it pales in comparison with the price of over $400,000 per year for Soliris, a drug used to treat a rare blood disorder.1 Recently, firms have increased their prices substantially for specialty drugs in response to perceived changes in willingness to pay by consumers and their insurance companies. In 2008, the price of a crucial antiseizure drug, H.P. Acthar Gel, which is used to treat children with a rare and severe form of epilepsy, increased from $1,600 to $23,000 per vial. Two courses of Acthar treatment for a severely ill 3-year-old girl, Reegan Schwartz, cost her father’s health plan about $226,000. Steve Cartt, an executive vice president at the drug’s manufacturer, Questcor, explained that this price increase was based on a review of the prices of other specialty drugs and estimates of how much of the price insurers and employers would be willing to bear. In 2013, 107 U.S. drug patents expired, including major products such as Cymbalta and OxyContin. When a patent for a highly profitable drug expires, many firms enter the market 1When asked to defend such prices, executives of pharmaceutical companies emphasize the high costs of drug development—in the hundreds of millions of dollars—that must be recouped from a relatively small number of patients with a given rare condition. 273 274 CHAPTER 9 Monopoly and sell generic (equivalent) versions of the brand-name drug.2 Generics account for nearly 70% of all U.S. prescriptions and half of Canadian prescriptions. Congress, when it passed laws permitting generic drugs to quickly enter a market after a patent expires, expected that patent expiration would subsequently lead to sharp declines in drug prices. If consumers view the generic product and the brand-name product as perfect substitutes, both goods will sell for the same price, and entry by many firms will drive the price down to the competitive level. Even if consumers view the goods as imperfect substitutes, one might expect the price of the brand-name drug to fall. However, the prices of many brand-name drugs have increased after their patents expired and generics entered the market. The generic drugs are relatively inexpensive, but the brandname drugs often continue to enjoy a significant market share and sell for high prices. Even after the patent for what was then the world’s largest selling drug, Lipitor, expired in 2011, it continued to sell for high prices despite competition from generics selling at much lower prices. Indeed, Regan (2008), who studied the effects of generic entry on post-patent price competition for 18 prescription drugs, found an average 2% increase in brand-name prices. Studies based on older data have found up to a 7% average increase. Why do some brandname prices rise after the entry of generic drugs? W hy can a firm with a patent-based monopoly charge a high price? Why might a brand-name pharmaceutical’s price rise after its patent expires? To answer these questions, we need to understand the decision-making process for a monopoly: the sole supplier of a good that has no close substitute.3 Monopolies have been common since ancient times. In the fifth century b.c., the Greek philosopher Thales gained control of most of the olive presses during a year of exceptionally productive harvests. The ancient Egyptian pharaohs controlled the sale of food. In England, until Parliament limited the practice in 1624, kings granted monopoly rights called royal charters to court favorites. Particularly valuable royal charters went to companies that controlled trade with North America, the Hudson Bay Company, and with India, the British East India Company. In modern times, government actions continue to play an important role in creating monopolies. For example, governments grant patents that allow the inventor of a new product to be the sole supplier of that product for up to 20 years. Similarly, until 1999, the U.S. government gave one company the right to be the sole registrar of Internet domain names. Many public utilities are government-owned or government-protected monopolies.4 2Under the 1984 Hatch-Waxman Act, the U.S. government allows a firm to sell a generic product after a brand-name drug’s patent expires if the generic-drug firm can prove that its product delivers the same amount of active ingredient or drug to the body in the same way as the brand-name product. Sometimes the same firm manufactures both a brand-name drug and an identical generic drug, so the two have identical ingredients. Generics produced by other firms usually differ in appearance and name from the original product and may have different nonactive ingredients but the same active ingredients. 3Analogously, a monopsony is the only buyer of a good in a given market. 4Whether the law views a firm as a monopoly depends on how broadly the market is defined. Is the market limited to a particular drug or the pharmaceutical industry as a whole? The manufacturer of the drug is a monopoly in the former case, but just one of many firms in the latter case. Thus, defining a market is critical in legal cases. A market definition depends on whether other products are good substitutes for those in that market. 9.1 Monopoly Profit Maximization 275 Unlike a competitive firm, which is a price taker (Chapter 8), a monopoly can set its price. A monopoly’s output is the market output, and the demand curve a monopoly faces is the market demand curve. Because the market demand curve is downward sloping, the monopoly (unlike a competitive firm) doesn’t lose all its sales if it raises its price. As a consequence, a profit-maximizing monopoly sets its price above marginal cost, the price that would prevail in a competitive market. Consumers buy less at this relatively high monopoly price than they would at the competitive price. M ain Topics 1. Monopoly Profit Maximization: Like all firms, a monopoly maximizes profit by setting its output so that its marginal revenue equals marginal cost. In this chapter, we examine six main topics 2. Market Power: A monopoly sets its price above the competitive level, which equals the marginal cost. 3. Market Failure Due to Monopoly Pricing: By setting its price above marginal cost, a monopoly creates a deadweight loss because the market fails to maximize total surplus. 4. Causes of Monopoly: Two important causes of monopoly are cost factors and government actions that restrict entry, such as patents. 5. Advertising: A monopoly advertises to shift its demand curve so as to increase its profit. 6. Networks, Dynamics, and Behavioral Economics: If its current sales affect a monopoly’s future demand curve, a monopoly may charge a low initial price so as to maximize its long-run profit. 9.1 Monopoly Profit Maximization All firms, including competitive firms and monopolies, maximize their profits by setting quantity such that marginal revenue equals marginal cost (Chapter 7). Chapter 6 demonstrates how to derive a marginal cost curve. We now derive the monopoly’s marginal revenue curve and then use the marginal revenue and marginal cost curves to examine how the manager of a monopoly sets quantity to maximize profit. Marginal Revenue A firm’s marginal revenue curve depends on its demand curve. We will show that a monopoly’s marginal revenue curve lies below its demand curve at any positive quantity because its demand curve is downward sloping. Marginal Revenue and Price. A firm’s demand curve shows the price, p, it receives for selling a given quantity, q. The price is the average revenue the firm receives, so a firm’s revenue is R = pq. A firm’s marginal revenue, MR, is the change in its revenue from selling one more unit. A firm that earns ΔR more revenue when it sells Δq extra units of output has a marginal revenue of ΔR . MR = Δq 276 CHAPTER 9 Monopoly If the firm sells exactly one more unit (Δq = 1), then its marginal revenue, MR, is ΔR (= ΔR/1). The marginal revenue of a monopoly differs from that of a competitive firm because the monopoly faces a downward-sloping demand curve, unlike the competitive firm. The competitive firm in panel a of Figure 9.1 faces a horizontal demand curve at the market price, p1. Because its demand curve is horizontal, the competitive firm can sell another unit of output without reducing its price. As a result, the marginal revenue it receives from selling the last unit of output is the market price. Initially, the competitive firm sells q units of output at the market price of p1, so its revenue, R1, is area A, which is a rectangle that is p1 * q. If the firm sells one more unit, its revenue is R2 = A + B, where area B is p1 * 1 = p1. The competitive firm’s marginal revenue equals the market price: ΔR = R2 - R1 = (A + B) - A = B = p1. A monopoly faces a downward-sloping market demand curve, as in panel b of Figure 9.1. (So far we have used q to represent the output of a single firm and Q to represent the combined market output of all firms in a market. Because a monopoly F IG U RE 9. 1 Average and Marginal Revenue The demand curve shows the average revenue or price per unit of output sold. (a) The competitive firm’s marginal revenue, area B, equals the market price, p1. (b) The monopoly’s marginal revenue is less than the price p2 by area C, the revenue lost due to a lower price on the Q units originally sold. (b) Monopoly p, $ per unit p, $ per unit (a) Competitive Firm Demand curve p1 p1 C p2 A Demand curve B A q Competition Monopoly q+1 q, Units per year B Q Q+1 Q, Units per year Initial Revenue, R1 Revenue with One More Unit, R2 Marginal Revenue, R2 - R1 A A+C A+B A+B B = p1 B − C = p2 − C 9.1 Monopoly Profit Maximization 277 is the only firm in the market, q and Q are identical, so we use Q to describe both the firm’s output and market output. The monopoly, which initially sells Q units at p1, can sell one extra unit only if it lowers its price to p2 on all units. The monopoly’s initial revenue, p1 * Q, is R1 = A + C. When it sells the extra unit, its revenue, p2 * (Q + 1), is R2 = A + B. Thus, its marginal revenue is ΔR = R2 - R1 = (A + B) - (A + C) = B - C. The monopoly sells the extra unit of output at the new price, p2 , so its extra revenue is B = p2 * 1 = p2. The monopoly loses the difference between the new price and the original price, Δp = (p2 - p1), on the Q units it originally sold: C = Δp * Q. Therefore the monopoly’s marginal revenue, B - C = p2 - C, is less than the price it charges by an amount equal to area C. Because the competitive firm in panel a can sell as many units as it wants at the market price, it does not have to cut its price to sell an extra unit, so it does not have to give up revenue such as Area C in panel b. It is the downward slope of the monopoly’s demand curve that causes its marginal revenue to be less than its price. For a monopoly to sell one more unit in a given period it must lower the price on all the units it sells that period, so its marginal revenue is less than the price obtained for the extra unit. The marginal revenue is this new price minus the loss in revenue arising from charging a lower price for all other units sold. The Marginal Revenue Curve. Thus, the monopoly’s marginal revenue curve lies below a downward-sloping demand curve at every positive quantity. The relationship between the marginal revenue and demand curves depends on the shape of the demand curve. For linear demand curves, the marginal revenue curve is a straight line that starts at the same point on the vertical (price) axis as the demand curve but has twice the slope. Therefore, the marginal revenue curve hits the horizontal (quantity) axis at half the quantity at which the demand curve hits the quantity axis. In Figure 9.2, the demand curve has a slope of -1 and hits the horizontal axis at 24 units, while the marginal revenue curve has a slope of -2 and hits the horizontal axis at 12 units. We now derive an equation for the monopoly’s marginal revenue curve. For a monopoly to increase its output by one unit, the monopoly lowers its price per unit by an amount indicated by the demand curve, as panel b of Figure 9.1 illustrates. Specifically, output demanded rises by one unit if price falls by the slope of the demand curve, Δp/ΔQ. By lowering its price, the monopoly loses (Δp/ΔQ) * Q on the units it originally sold at the higher price (area C), but it earns an additional p on the extra output it now sells (area B). Thus, the monopoly’s marginal revenue is MR = p + Δp ΔQ Q. (9.1) Because the slope of the monopoly’s demand curve, Δp/ΔQ, is negative, the last term in Equation 9.1, (Δp/ΔQ)Q, is negative. Equation 9.1 confirms that the price is greater than the marginal revenue, which equals p plus a negative term and must therefore be less than the price. We now use Equation 9.1 to derive the marginal revenue curve when the monopoly faces the linear inverse demand function (Chapter 3) p = 24 - Q, (9.2) 278 CHAPTER 9 Monopoly F IG U RE 9. 2 Elasticity of Demand and Total, Average, and Marginal Revenue p, $ per unit The demand curve (or average revenue curve), p = 24 - Q, lies above the marginal revenue curve, MR = 24 - 2Q. Where the marginal revenue equals 24 zero, Q = 12, the elasticity of demand is ε = - 1. For larger quantities, the marginal revenue is negative, so the MR curve is below the horizontal axis. Perfectly elastic, ε→ –∞ Elastic, ε < –1 ΔMR = –2 Δp = –1 ΔQ = 1 ΔQ = 1 ε = –1 12 Inelastic, –1 < ε < 0 Marginal Revenue (MR = 24 – 2Q ) 0 Demand ( p = 24 – Q ) 12 Perfectly inelastic, ε = 0 24 Q, Units per day that Figure 9.2 illustrates. Equation 9.2 shows that the price consumers are willing to pay falls $1 if quantity increases by one unit. More generally, if quantity increases by ΔQ, price falls by Δp = - ΔQ. Thus, the slope of the demand curve is Δp/ΔQ = -1. We obtain the marginal revenue function for this monopoly by substituting into Equation 9.1 the actual slope of the demand function, Δp/ΔQ = -1, and replacing p with 24 - Q (using Equation 9.2): MR = p + Δp ΔQ Q = (24 - Q) + (-1)Q = 24 - 2Q. (9.3) Figure 9.2 shows a plot of Equation 9.3. The slope of this marginal revenue curve is ΔMR/ΔQ = -2, so the marginal revenue curve is twice as steep as the demand curve. Using Calculus Deriving a Monopoly’s Marginal Revenue Function Using calculus, if a firm’s revenue function is R(Q), then its marginal revenue function is defined as MR(Q) = dR(Q) . dQ For our example, where the inverse demand function is p = 24 - Q, the revenue function is R(Q) = (24 - Q)Q = 24Q - Q2. (9.4) 9.1 Monopoly Profit Maximization 279 By differentiating Equation 9.4 with respect to Q, we obtain the marginal revenue function, MR(Q) = dR(Q)/dQ = 24 - 2Q, which is the same as Equation 9.3. Q&A 9.1 Given a general linear inverse demand curve p(Q) = a - bQ, where a and b are positive constants, use calculus to show that the marginal revenue curve is twice as steeply sloped as the inverse demand curve. Answer 1. Differentiate a general inverse linear demand curve with respect to Q to determine its slope. The derivative of the linear inverse demand function with respect to Q is dp(Q) dQ = d(a - bQ) = -b. dQ 2. Differentiate the monopoly’s revenue function with respect to Q to obtain the marginal revenue function, then differentiate the marginal revenue function with respect to Q to determine its slope. The monopoly’s revenue function is R(Q) = p(Q)Q = (a - bQ)Q = aQ - bQ2. Differentiating the revenue function with respect to quantity, we find that the marginal revenue function is linear, MR(Q) = dR(Q)/dQ = a - 2bQ. Thus, the slope of the marginal revenue curve, dMR(Q) = -2b, dQ is twice that of the inverse demand curve, dp/dQ = -b. Comment: Note that the vertical axis intercept is a for both the inverse demand and MR curves. Thus, if the demand curve is linear, its marginal revenue curve is twice as steep and intercepts the horizontal axis at half the quantity as does the demand curve. Marginal Revenue and Price Elasticity of Demand. The marginal revenue at any given quantity depends on the demand curve’s height (the price) and shape. The shape of the demand curve at a particular quantity is described by the price elasticity of demand (Chapter 3), ε = (ΔQ/Q)/(Δp/p) 6 0, which tells us the percentage by which quantity demanded falls as the price increases by 1%. At a given quantity, the marginal revenue equals the price times a term involving the elasticity of demand (Chapter 3):5 MR = p¢ 1 + 1 ≤. ε (9.5) 5By multiplying the last term in Equation 9.1 by p/p (= 1) and using algebra, we can rewrite the expression as MR = p + p Δp Q ΔQ p = pJ1 + 1 R. (ΔQ/Δp)(p/Q) The last term in this expression is 1/ε, because ε = (ΔQ/Δp)(p/Q). Monopoly According to Equation 9.5, marginal revenue is closer to price as demand becomes more elastic. Where the demand curve hits the price axis (Q = 0), the demand curve is perfectly elastic, so the marginal revenue equals price: MR = p.6 Where the demand elasticity is unitary, ε = -1, marginal revenue is zero: MR = p[1 + 1/(-1)] = 0. Marginal revenue is negative where the demand curve is inelastic, -1 6 ε … 0. With the demand function in Equation 9.2, ΔQ/Δp = -1, so the elasticity of demand is ε = (ΔQ/Δp)(p/Q) = -p/Q. Table 9.1 shows the relationship among quantity, price, marginal revenue, and elasticity of demand for this linear example. As Q approaches 24, ε approaches 0, and marginal revenue is negative. As Q approaches zero, the demand becomes increasingly elastic, and marginal revenue approaches the price. Choosing Price or Quantity Any firm maximizes its profit by operating where its marginal revenue equals its marginal cost. Unlike a competitive firm, a monopoly can adjust its price, so it has a choice of setting its price or its quantity to maximize its profit. (A competitive firm sets its quantity to maximize profit because it cannot affect market price.) T A B L E 9 . 1 Quantity, Price, Marginal Revenue, and Elasticity for the Linear Inverse Demand Function p = 24 - Q Quantity, Q Price, p Marginal Revenue, MR Elasticity of Demand, ε = -p/Q 0 24 24 -∞ 1 23 22 -23 2 22 20 -11 3 21 18 -7 4 20 16 -5 5 19 14 -3.8 6 18 12 -3 7 17 10 -2.43 8 16 8 -2 9 15 6 -1.67 10 14 4 -1.4 11 13 2 -1.18 12 12 0 13 11 -2 - 0.85 f f f f 23 1 -22 24 0 -24 more elastic S CHAPTER 9 -1 - 0.043 0 d less elastic 280 6As ε approaches - ∞ (perfectly elastic demand), the 1/ε term approaches zero, so MR = p(1 + 1/ε) approaches p. 9.1 Monopoly Profit Maximization 281 Whether the monopoly sets its price or its quantity, the other variable is determined by the market demand curve. Because the demand curve slopes down, the monopoly faces a trade-off between a higher price and a lower quantity or a lower price and a higher quantity. A profit-maximizing monopoly chooses the point on the demand curve that maximizes its profit. Unfortunately for the monopoly, it cannot set both its quantity and its price, such as a point that lies above its demand curve. If it could do so, the monopoly would choose an extremely high price and an extremely large output and would earn a very high profit. However, the monopoly cannot choose a point that lies above the demand curve. If the monopoly sets its price, the demand curve determines how much output it sells. If the monopoly picks an output level, the demand curve determines the price. Because the monopoly wants to operate at the price and output at which its profit is maximized, it chooses the same profit-maximizing solution whether it sets the price or output. Thus, setting price and setting quantity are equivalent for a monopoly. In the following discussion, we assume that the monopoly sets quantity. Two Steps to Maximizing Profit All profit-maximizing firms, including monopolies, use a two-step analysis to determine the output level that maximizes their profit (Chapter 7). First, the firm determines the output, Q*, at which it makes the highest possible profit (or minimizes its loss). Second, the firm decides whether to produce Q* or shut down. Profit-Maximizing Output. In Chapter 7, we saw that profit is maximized where marginal profit equals zero. Equivalently, because marginal profit equals marginal revenue minus marginal cost (Chapter 7), marginal profit is zero where marginal revenue equals marginal cost. To illustrate how a monopoly chooses its output to maximize its profit, we use the same linear demand and marginal revenue curves as above and add a linear marginal cost curve in panel a of Figure 9.3. Panel b shows the corresponding profit curve. The marginal revenue curve, MR, intersects the marginal cost curve, MC, at 6 units in panel a. The corresponding price, 18, is the height of the demand curve, point e, at 6 units. The profit, π, is the gold rectangle. The height of this rectangle is the average profit per unit, p - AC = 18 - 8 = 10. The length of the rectangle is 6 units. Thus, the area of the rectangle is the average profit per unit times the number of units, which is the profit, π = 60. The profit at 6 units is the maximum possible profit: The profit curve in panel b reaches its peak, 60, at 6 units. At the peak of the profit curve, the marginal profit is zero, which is consistent with the marginal revenue equaling the marginal cost. Why does the monopoly maximize its profit by producing where its marginal revenue equals its marginal cost? At smaller quantities, the monopoly’s marginal revenue is greater than its marginal cost, so its marginal profit is positive—the profit curve is upward sloping. By increasing its output, the monopoly raises its profit. Similarly, at quantities greater than 6 units, the monopoly’s marginal cost is greater than its marginal revenue, so its marginal profit is negative, and the monopoly can increase its profit by reducing its output. As Figure 9.2 illustrates, the marginal revenue curve is positive where the elasticity of demand is elastic, is zero at the quantity where the demand curve has a unitary 282 CHAPTER 9 Monopoly F IG U RE 9. 3 Maximizing Profit (a) Monopolized Market p, $ per unit (a) At Q = 6, where marginal revenue, MR, equals marginal cost, MC, profit is maximized. The rectangle shows that the profit is $60, where the height of the rectangle is the average profit per unit, p - AC = $18 - $8 = $10, and the length is the number of units, 6. (b) Profit is maximized at Q = 6 (where marginal revenue equals marginal cost). MC 24 AC AVC e 18 π = 60 12 8 6 MR 0 6 12 Demand 24 Q, Units per day π, $ (b) Profit 60 0 Profit, π 6 12 Q, Units per day elasticity, and is negative at larger quantities where the demand curve is inelastic. Because the marginal cost curve is never negative, the marginal revenue curve can only intersect the marginal cost curve where the marginal revenue curve is positive, in the range in which the demand curve is elastic. That is, a monopoly’s profit is maximized in the elastic portion of the demand curve. In our example, profit is maximized at Q = 6, where the elasticity of demand is -3. A profit-maximizing monopoly never operates in the inelastic portion of its demand curve. The Shutdown Decision. A monopoly shuts down to avoid making a loss in the short run if its price is below its average variable cost at its profit-maximizing (or loss-minimizing) quantity (Chapter 7). In the long run, the monopoly shuts down if the price is less than its average cost. In the short-run example in Figure 9.3, the average variable cost, AVC = 6, is less than the price, p = 18, at the profit-maximizing output, Q = 6, so the firm chooses to produce. Price is also above average cost at Q = 6, so the average profit per unit, p - AC is positive (the height of the gold profit rectangle), so the monopoly makes a positive profit. 9.1 Monopoly Profit Maximization Using Calculus Solving for the Profit-Maximizing Output 283 We can also solve for the profit-maximizing quantity mathematically. We already know the demand and marginal revenue functions for this monopoly. We need to determine its cost curves. The monopoly’s cost is a function of its output, C(Q). In Figure 9.3, we assume that the monopoly faces a short-run cost function of C(Q) = 12 + Q2, (9.6) where Q2 is the monopoly’s variable cost as a function of output and 12 is its fixed cost. Given this cost function, Equation 9.6, the monopoly’s marginal cost function is dC(Q) = MC(Q) = 2Q. dQ (9.7) This marginal cost curve in panel a is a straight line through the origin with a slope of 2. The average variable cost is AVC = Q2/Q = Q, so it is a straight line through the origin with a slope of 1. The average cost is AC = C/Q = (12 + Q2)/Q = 12/Q + Q, which is U-shaped. Using Equations 9.4 and 9.6, we can write the monopoly’s profit as π(Q) = R(Q) - C(Q) = (24Q - Q2) - (12 + Q2). By setting the derivative of this profit function with respect to Q equal to zero, we have an equation that determines the profit-maximizing output: dπ(Q) dR(Q) dC(Q) = dQ dQ dQ = MR - MC = (24 - 2Q) - 2Q = 0. That is, MR = 24 - 2Q = 2Q = MC. To determine the profit-maximizing output, we solve this equation and find that Q = 6. Substituting Q = 6 into the inverse demand function (Equation 9.2), we learn that the profit-maximizing price is p = 24 - Q = 24 - 6 = 18. Should the monopoly operate at Q = 6? At that quantity, average variable cost is AVC = Q2/Q = 6, which is less than the price, so the firm does not shut down. The average cost is AC = (6 + 12/6) = 8, which is less than the price, so the firm makes a profit. Effects of a Shift of the Demand Curve Shifts in the demand curve or marginal cost curve affect the profit-maximizing monopoly price and quantity and can have a wider variety of effects with a monopoly than with a competitive market. In a competitive market, the effect of a shift in demand on a competitive firm’s output depends only on the shape of the 284 CHAPTER 9 Monopoly marginal cost curve. In contrast, the effect of a shift in demand on a monopoly’s output depends on the shapes of both the marginal cost curve and the demand curve. As we saw in Chapter 8, a competitive firm’s marginal cost curve tells us everything we need to know about the amount that the firm is willing to supply at any given market price. The competitive firm’s supply curve is its upward-sloping marginal cost curve above its minimum average variable cost. A competitive firm’s supply behavior does not depend on the shape of the market demand curve because it always faces a horizontal demand curve at the market price. Thus, if we know a competitive firm’s marginal cost curve, we can predict how much that firm will produce at any given market price. In contrast, a monopoly’s output decision depends on the shapes of its marginal cost curve and its demand curve. Unlike a competitive firm, a monopoly does not have a supply curve. Knowing the monopoly’s marginal cost curve is not enough for us to predict how much a monopoly will sell at any given price. Figure 9.4 illustrates that the relationship between price and quantity is unique in a competitive market but not in a monopolistic market. If the market is competitive, the initial equilibrium is e1 in panel a, where the original demand curve D1 intersects the supply curve, MC, which is the sum of the marginal cost curves of a large number of competitive firms. When the demand curve shifts to D2, the new competitive equilibrium, e2, has a higher price and quantity. A shift of the demand curve maps out competitive equilibria along the marginal cost curve, so every equilibrium quantity has a single corresponding equilibrium price. For the monopoly in panel b, as the demand curve shifts from D1 to D2, the profit-maximizing monopoly outcome shifts from E1 to E2, so the price rises but the quantity stays constant, Q1 = Q2. Thus, a given quantity can correspond to more than one profit-maximizing price, depending on the position of the demand curve. A shift in F IG U RE 9. 4 Effects of a Shift of the Demand Curve (a) A shift of the demand curve from D1 to D2 causes the competitive equilibrium to move from e1 to e2 along the supply curve (which is the horizontal sum of the marginal cost curves of all the competitive firms). Because the competitive equilibrium lies on the supply curve, each quantity (such as Q1 and Q2) corresponds to only one possible equilibrium price. (b) With a monopoly, this same shift of p, $ per unit (b) Monopoly p, $ per unit (a) Competition MC, Supply curve MC E2 p2 e2 p2 p1 demand causes the monopoly optimum to change from E1 to E2. The monopoly quantity stays the same, but the monopoly price rises. Thus, a shift in demand does not map out a unique relationship between price and quantity in a monopolized market. The same quantity, Q1 = Q2, is associated with two different prices, p1 and p2. E1 p1 e1 MR1 D2 Q1 Q 2 D1 Q, Units per year MR 2 Q 1 = Q2 D2 D1 Q, Units per year 9.2 Market Power 285 the demand curve may cause the profit-maximizing price to stay constant while the quantity changes. More commonly, both the profit-maximizing price and quantity would change. 9.2 Market Power A monopoly has market power, which is the ability to significantly affect the market price. In contrast, no single competitive firm can significantly affect the market price. A profit-maximizing monopoly charges a price that exceeds its marginal cost. The extent to which the monopoly price exceeds marginal cost depends on the shape of the demand curve. Market Power and the Shape of the Demand Curve If the monopoly faces a highly elastic—nearly flat—demand curve at the profitmaximizing quantity, it would lose substantial sales if it raised its price by even a small amount. Conversely, if the demand curve is not very elastic (relatively steep) at that quantity, the monopoly would lose fewer sales from raising its price by the same amount. We can derive the relationship between markup of price over marginal cost and the elasticity of demand at the profit-maximizing quantity using the expression for marginal revenue in Equation 9.5 and the firm’s profit-maximizing condition that marginal revenue equals marginal cost: MR = p¢ 1 + 1 ≤ = MC. ε (9.8) By rearranging terms, we see that a profit-maximizing manager chooses quantity such that p MC = 1 . 1 + (1/ε) (9.9) In our linear demand example in panel a of Figure 9.3, the elasticity of demand is ε = -3 at the monopoly optimum where Q = 6. As a result, the ratio of price to marginal cost is p/MC = 1/[1 + 1/(-3)] = 1.5, or p = 1.5MC. The profit-maximizing price, $18, in panel a is 1.5 times the marginal cost of $12. Table 9.2 illustrates how the ratio of price to marginal cost varies with the elasticity of demand. When the elasticity is -1.01, only slightly elastic, the monopoly’s profit-maximizing price is 101 times larger than its marginal cost: p/MC = 1/[1 + 1/(-1.01)] ≈ 101. As the elasticity of demand approaches negative infinity (becomes perfectly elastic), the ratio of price to marginal cost shrinks to p/MC = 1.7 Thus, even in the absence of rivals, the shape of the demand curve constrains the monopolist’s ability to exercise market power. 7As the elasticity approaches negative infinity, 1/ε approaches zero, so 1/(1 + 1/ε) approaches 1/1 = 1. 286 CHAPTER 9 Monopoly T A BLE 9 .2 Elasticity of Demand, Price, and Marginal Cost d more elastic less elastic S Elasticity of Demand, ε Ma nagerial I mplication Checking Whether the Firm Is Maximizing Profit Mini-Case Cable Cars and Profit Maximization Price/Marginal Cost Ratio, p/MC = 1/[1 + (1/ε)] Lerner Index, (p - MC)/p = -1/ε - 1.01 101 0.99 - 1.1 11 0.91 -2 2 0.5 -3 1.5 0.33 -5 1.25 0.2 - 10 1.11 0.1 - 100 1.01 0.01 -∞ 1 0 A manager can use this last result to determine whether the firm is maximizing its profit. Typically a monopoly knows its costs accurately, but is somewhat uncertain about the demand curve it faces and hence what price (or quantity) to set. Many private firms—such as ACNielsen, IRI, and IMS Health—and industry groups collect data on quantities and prices in a wide variety of industries including automobiles, foods and beverages, drugs, and many services. Firms can use these data to estimate the firm’s demand curve (Chapter 3). More commonly, firms hire consulting firms (often the same firms that collect data) to estimate the elasticity of demand facing their firm. A manager can use the estimated elasticity of demand to check whether the firm is maximizing profit. If the p/MC ratio does not approximately equal 1/(1 + 1/ε), as required by Equation 9.9, then the manager knows that the firm is not setting its price to maximize its profit. Of course, the manager can also check whether the firm is maximizing profit by varying its price or quantity. However, often such experiments may be more costly than using statistical techniques to estimate the elasticity of demand. Since San Francisco’s cable car system started operating in 1873, it has been one of the city’s main tourist attractions. In 2005, the cash-strapped Municipal Railway raised the one-way fare by two-thirds from $3 to $5. Not surprisingly, the number of riders dropped substantially, and many in the city called for a rate reduction. The rate increase prompted many locals to switch to buses or other forms of transportation, but most tourists have a relatively inelastic demand curve for cable car rides. Frank Bernstein of Arizona, who visited San Francisco with his wife, two children, and mother-in-law, said they would not visit San Francisco without riding a cable car: “That’s what you do when you’re here.” But the round-trip $50 cost for his family to ride a cable car from the Powell Street turnaround to Fisherman’s Wharf and back “is a lot of money for our family. We’ll do it once, but we won’t do it again.” 9.2 Market Power 287 If the city ran the cable car system like a profit-maximizing monopoly, the decision to raise fares would be clear. The 67% rate hike resulted in a 23% increase in revenue to $9,045,792 in the 2005–2006 fiscal year. Given that the revenue increased when the price rose, the city must have been operating in the inelastic portion of its demand curve (ε 7 -1), where MR = p(1 + 1/ε) 6 0 prior to the fare increase.8 With fewer riders, costs stayed constant (they would have fallen if the city had decided to run fewer than its traditional 40 cars), so the city’s profit increased given the increase in revenue. Presumably the profitmaximizing price is even higher in the elastic portion of the demand curve. However, the city may not be interested in maximizing its profit on the cable cars. At the time, then-Mayor Gavin Newsom said that having fewer riders “was my biggest fear when we raised the fare. I think we’re right at the cusp of losing visitors who come to San Francisco and want to enjoy a ride on a cable car.” The mayor said that he believed keeping the price of a cable car ride relatively low helps attract tourists to the city, thereby benefiting many local businesses. Newsom observed, “Cable cars are so fundamental to the lifeblood of the city, and they represent so much more than the revenue they bring in.” The mayor decided to continue to run the cable cars at a price below the profit-maximizing level. The fare stayed at $5 for six years, then rose to $6 in 2011 and has stayed there through at least the first half of 2013. The Lerner Index Another way to show how the elasticity of demand affects a monopoly’s price relative to its marginal cost is to look at the firm’s Lerner Index (or price markup)—the ratio of the difference between price and marginal cost to the price: (p - MC)/p. This index can be calculated for any firm, whether or not the firm is a monopoly. The Lerner Index is zero for a competitive firm because a competitive firm produces where marginal cost equals price. The Lerner Index measures a firm’s market power: the larger the difference between price and marginal cost, the larger the Lerner Index. If the firm is maximizing its profit, we can express the Lerner Index in terms of the elasticity of demand by rearranging Equation 9.9: p - MC 1 = - . p ε 8The (9.10) marginal revenue is the slope of the revenue function. Thus, if a reduction in quantity causes the revenue to increase, the marginal revenue must be negative. As Figure 9.2 illustrates, marginal revenue is negative in the inelastic portion of the demand curve. 288 CHAPTER 9 Monopoly The Lerner Index ranges between 0 and 1 for a profit-maximizing monopoly.9 Equation 9.10 confirms that a competitive firm has a Lerner Index of zero because its demand curve is perfectly elastic.10 As Table 9.2 illustrates, the Lerner Index for a monopoly increases as the demand becomes less elastic. If ε = -5, the monopoly’s markup (Lerner Index) is 1/5 = 0.2; if ε = -2, the markup is 1/2 = 0.5; and if ε = -1.01, the markup is 0.99. Monopolies that face demand curves that are only slightly elastic set prices that are multiples of their marginal cost and have Lerner Indexes close to 1. M ini-Case Apple’s iPad Apple started selling the iPad on April 3, 2010. The iPad was not the first tablet. Indeed, it wasn’t Apple’s first tablet: Apple sold another tablet, the Newton, from 1993–1998. But it was the most elegant one, and the first one large numbers of consumers wanted to own. Users interact with the iPad using Apple’s multitouch, finger-sensitive touchscreen (rather than a pressure-triggered stylus that most previous tablets used) and a virtual onscreen keyboard (rather than a physical one). Most importantly, the iPad offered an intuitive interface and was very well integrated with Apple’s iTunes, eBooks, and various application programs. People loved the original iPad. Even at $499 for the basic model, Apple had a virtual monopoly in its first year. According to the research firm IDC, Apple’s share of the 2010 tablet market was 87%. Moreover, the other tablets available in 2010 were not viewed by most consumers as close substitutes. Apple reported that it sold 25 million iPads worldwide in its first full year, 2010–2011. According to one estimate, the basic iPad’s marginal cost was MC = $220, so its Lerner Index was (p - MC)/p = (499 - 220)/499 = 0.56. Within a year of the iPad’s introduction, over a hundred iPad want-to-be tablets were launched. To maintain its dominance, Apple replaced the original iPad with the feature-rich iPad 2 in 2011, added the enhanced iPad 3 in 2012, and cut the price of the iPad 2 by $100 in 2012. According to court documents Apple filed in 2012, its Lerner Index fell to between 0.23 and 0.32. Industry experts believe that Apple can produce tablets at far lower cost than most if not all of its competitors. Apple has formed strategic partnerships with other companies to buy large supplies of components, securing a lower price from suppliers than its competitors. Using its own patents, Apple avoids paying as many licensing fees as do other firms. Copycat competitors with 10″ screens have gained some market share from Apple. More basic tablets with smaller 7″ screens that are little more than e-readers have sold a substantial number of units, so that the iPad’s share of the total tablet market was 68% in the first quarter of 2012. ε would have to be a negative fraction, indicating that the demand curve was inelastic at the monopoly’s output choice. However, as we’ve already seen, a profit-maximizing monopoly never operates in the inelastic portion of its demand curve. 9For the Lerner Index to be above 1 in Equation 9.10, 10As the elasticity of demand approaches negative infinity, the Lerner Index, -1/ε, approaches zero. 9.2 Market Power Q& A 9.2 289 When the iPad was introduced, Apple’s constant marginal cost of producing this iPad was about $220. We estimate that Apple’s inverse demand function for the iPad was p = 770 - 11Q, where Q is the millions of iPads purchased.11 What was Apple’s marginal revenue function? What were its profit-maximizing price and quantity? Given that the Lerner Index for the iPad was (p - MC)/p = 0.56 (see the “Apple’s iPad” Mini-Case), what was the elasticity of demand at the profit-maximizing level? Answer 1. Derive Apple’s marginal revenue function using the information about its demand function. Given that Apple’s inverse demand function was linear, p = 770 - 11Q, its marginal revenue function has the same intercept and twice the slope: MR = 770 - 22Q.12 2. Derive Apple’s profit-maximizing quantity and price by equating the marginal revenue and marginal cost functions and solving. Apple maximized its profit where MR = MC: 770 - 22Q = 220. Solving this equation for the profit-maximizing output, we find that Q = 25 million iPads. By substituting this quantity into the inverse demand function, we determine that the profit-maximizing price was p = $495 per unit. 3. Use Equation 9.10 to infer Apple’s demand elasticity based on its Lerner Index. We can write Equation 9.10 as (p - MC)/p = 0.56 = -1/ε. Solving this last equality for ε, we find that ε ≈ -1.79. (Of course, we could also calculate the demand elasticity by using the demand function.) Sources of Market Power What factors cause a monopoly to face a relatively elastic demand curve and hence have little market power? Ultimately, the elasticity of demand of the market demand curve depends on consumers’ tastes and options. The more consumers want a good—the more willing they are to pay “virtually anything” for it—the less elastic is the demand curve. Other things equal, the demand curve a firm (not necessarily a monopoly) faces becomes more elastic as (1) better substitutes for the firm’s product are introduced, (2) more firms enter the market selling the same product, or (3) firms that provide the same service locate closer to this firm. The demand curves for Xerox, the U.S. Postal Service, and McDonald’s have become more elastic in recent decades for these three reasons. When Xerox started selling its plain-paper copier, no other firm sold a close substitute. Other companies’ machines produced copies on special heat-sensitive paper 11See the Sources for “Pricing Apple’s iPad” for details on these estimates. 12Alternatively, we can use calculus to derive the marginal revenue curve. Multiplying the inverse demand function by Q to obtain Apple’s revenue function, R = 770Q - 11Q2. Then, we derive the marginal revenue function by differentiating the revenue with respect to quantity: MR = dR/dQ = 770 - 22Q. 290 CHAPTER 9 Monopoly that yellowed quickly. As other firms developed plain-paper copiers, the demand curve that Xerox faced became more elastic. In the past, the U.S. Postal Service (USPS) had a monopoly in overnight delivery services. Now FedEx, United Parcel Service, and many other firms compete with the USPS in providing overnight deliveries. Because of these increases in competition, the USPS’s share of business and personal correspondence fell from 77% in 1988 to 59% in 1996. Its total mail volume fell 40% from 2006 to 2010. Its overnight market fell to 15% by 2010.13 Compared to when it was a monopoly, the USPS’s demand curves for first-class mail and package delivery have shifted downward and become more elastic. As you drive down a highway, you may notice that McDonald’s restaurants are located miles apart. The purpose of this spacing is to reduce the likelihood that two McDonald’s outlets will compete for the same customer. Although McDonald’s can prevent its own restaurants from competing with each other, it cannot prevent Wendy’s or Burger King from locating near its restaurants. As other fast-food restaurants open near a McDonald’s, that restaurant faces a more elastic demand. What happens as a profit-maximizing monopoly faces more elastic demand? It has to lower its price. 9.3 Market Failure Due to Monopoly Pricing Unlike perfect competition, which achieves economic efficiency—that is, maximizes total surplus, TS (= consumer surplus + producer surplus = CS + PS)—a profitmaximizing monopoly is economically inefficient because it wastes potential surplus, resulting in a deadweight loss. The inefficiency of monopoly pricing is an example of a market failure: a non-optimal allocation of goods and services such that a market does not achieve economic efficiency. Market failure often occurs because the price differs from the marginal cost, as with a monopoly. This economic inefficiency creates a rationale for governments to intervene, as we discuss in Chapter 16. Total surplus (Chapter 8) is lower under monopoly than under competition. That is, monopoly destroys some of the potential gains from trade. Chapter 8 showed that competition maximizes total surplus because price equals marginal cost. By setting its price above its marginal cost, a monopoly causes consumers to buy less than the competitive level of the good, so society suffers a deadweight loss. If the monopoly were to act like a competitive market, it would produce where the marginal cost curve cuts the demand curve—the output where price equals marginal 13Peter Passell, “Battered by Its Rivals,” New York Times, May 15, 1997, C1; Grace Wyler, “11 Things You Should Know about the U.S. Postal Service Before It Goes Bankrupt,” Business Insider, May 31, 2011; “The U.S. Postal Service Nears Collapse,” BloombergBusinessweek, May 26, 2011; www .economicfreedom.org/2012/12/12/stamping-out-waste. 9.3 Market Failure Due to Monopoly Pricing 291 cost. For example, using the demand curve given by Equation 9.2 and the marginal cost curve given by Equation 9.7, p = 24 - Q = 2Q = MC. Solving this equation, we find that the competitive quantity, Qc, would be 8 units and the price would be $16, as Figure 9.5 shows. At this competitive price, consumer surplus is area A + B + C and producer surplus is D + E. If instead the firm acts like a profit-maximizing monopoly and operates where its marginal revenue equals its marginal cost, the monopoly output Qm is only 6 units and the monopoly price is $18. Consumer surplus is only A. Part of the lost consumer surplus, B, goes to the monopoly, but the rest, C, is lost. The benefit of being a monopoly is that it allows the firm to extract some consumer surplus from consumers and convert it to profit. By charging the monopoly price of $18 instead of the competitive price of $16, the monopoly receives $2 more per unit and earns an extra profit of area B = $12 on the F IG U RE 9. 5 Deadweight Loss of Monopoly p, $ per unit A competitive market would produce Qc = 8 at pc = $16, where the demand curve intersects the marginal cost (supply) curve. A monopoly produces only Qm = 6 at pm = $18, where the marginal revenue curve intersects the marginal cost curve. Under monopoly, consumer surplus is A, producer surplus is B + D, and the inefficiency or deadweight loss of monopoly is -C - E. 24 MC pm = 18 A = $18 B = $12 pc = 16 MR = MC = 12 D = $60 em C = $2 ec E = $4 Demand MR 0 Consumer Surplus, CS Producer Surplus, PS Total Surplus, TS = CS + PS Qm = 6 Qc = 8 12 24 Q, Units per day Competition Monopoly Change A+B+C D+E A B+D −B − C = ΔCS B − E = ΔPS A+B+C+D+E A+B+D −C − E = ΔTS = DWL 292 CHAPTER 9 Monopoly Qm = 6 units it sells. The monopoly loses area E, however, because it sells less than the competitive output. Consequently, the monopoly’s producer surplus increases by B - E over the competitive level. Monopoly pricing increases producer surplus relative to competition. Total surplus is less under monopoly than under competition. The deadweight loss of monopoly is -C - E, which represents the potential surplus that is wasted because less than the competitive output is produced. The deadweight loss is due to the gap between price and marginal cost at the monopoly output. At Qm = 6, the price, $18, is above the marginal cost, $12, so consumers are willing to pay more for the last unit of output than it costs to produce it. Q& A 9.3 In the linear example in panel a of Figure 9.3, how does charging the monopoly a specific tax of τ = $8 per unit affect the profit-maximizing price and quantity and the well-being of consumers, the monopoly, and society (where total surplus includes the tax revenue)? What is the tax incidence on consumers (the increase in the price they pay as a fraction of the tax)? Answer 1. Determine how imposing the tax affects the monopoly price and quantity. In the accompanying graph, the intersection of the marginal revenue curve, MR, and the before-tax marginal cost curve, MC 1, determines the monopoly quantity, Q1 = 6. At the before-tax solution, e1, the price is p1 = 18. The specific tax causes the monopoly’s before-tax marginal cost curve, MC 1 = 2Q, to shift upward by 8 to MC 2 = MC 1 + 8 = 2Q + 8. After the tax is applied, the monopoly operates where MR = 24 - 2Q = 2Q + 8 = MC 2. In the aftertax monopoly solution, e2, the quantity is Q2 = 4 and the price is p2 = 20. Thus, output falls by ΔQ = 6 - 4 = 2 units and the price increases by Δp = 20 - 18 = 2. 2. Calculate the change in the various surplus measures. The graph shows how the surplus measures change. Area G is the tax revenue collected by the government, τQ = 32, because its height is the distance between the two marginal cost curves, τ = 8, and its width is the output the monopoly produces after the tax is imposed, Q = 4. The tax reduces consumer and producer surplus and increases the deadweight loss. We know that producer surplus falls because (a) the monopoly could have produced this reduced output level in the absence of the tax but did not because it was not the profit-maximizing output, so its before-tax profit falls, and (b) the monopoly must now pay taxes. The beforetax deadweight loss from monopoly is -F. The after-tax deadweight loss is -C - E - F, so the increase in deadweight loss due to the tax is -C - E. The table below the graph shows that consumer surplus changes by -B - C and producer surplus by B - E - G. 3. Calculate the incidence of the tax on consumers. Because the tax goes from 0 to 8, the change in the tax is Δτ = 8. Because the change in the price that the consumer pays is Δp = 2, the share of the tax paid by consumers is Δp/Δτ = 2/8 = 14. Thus, the monopoly absorbs $6 of the tax and passes on only $2. p, $ per unit 9.4 Causes of Monopoly 293 MC 2 (after tax) 24 Monopoly Before Tax Consumer Surplus, CS A p2 = 20 Surplus, PS Producer e2 Monopoly After Tax MC 1 (before tax) A A + B + C D + E +τG= $8 B Tax T = τQ C 0 e1 18 p =Revenues, 1 Change -B - C = ΔCS B + D B - E - G = ΔPS G G = ΔT -C - E = ΔTS Total Surplus, A + B + C + D + E + G A + B + D + G E F TS = CS + PS D+ T Deadweight Loss, DWL -F -C - E - F -C - E = ΔDWL 8 G MR 0 Q2 = 4 Q1 = 6 Demand 12 24 Q, Units per day Consumer Surplus, CS Producer Surplus, PS Tax Revenues, T = τQ Total Surplus, TS = CS + PS + T Deadweight Loss, DWL 9.4 Monopoly Before Tax Monopoly After Tax Change A+B+C D+E+G 0 A B+D G −B − C = ΔCS B − E − G = ΔPS G = ΔT A+B+C+D+E+G −F A+B+D+G −C − E − F −C − E = ΔTS −C − E = ΔDWL Causes of Monopoly Why are some markets monopolized? The two most important reasons are cost considerations and government policy.14 14In later chapters, we discuss other means by which monopolies are created. One method is the merger of several firms into a single firm. This method creates a monopoly if new firms fail to enter the market. A second method is for a monopoly to use strategies that discourage other firms from entering the market. A third possibility is that firms coordinate their activities and set their prices as a monopoly would. Firms that act collectively in this way are called a cartel rather than a monopoly. 294 CHAPTER 9 Monopoly Cost-Based Monopoly Certain cost structures may facilitate the creation of a monopoly. One possibility is that a firm may have substantially lower costs than potential rivals. A second possibility is that the firms in an industry have cost functions such that one firm can produce any given output at a lower cost than two or more firms can. Cost Advantages. If a low-cost firm profitably sells at a price so low that other potential competitors with higher costs would lose money, no other firms enter the market. Thus, the low-cost firm is a monopoly. A firm can have a cost advantage over potential rivals for several reasons. It may have a superior technology or a better way of organizing production.15 For example, Henry Ford’s methods of organizing production using assembly lines and standardization allowed him to produce cars at substantially lower cost than rival firms until they copied his organizational techniques. If a firm controls an essential facility or a scarce resource that is needed to produce a particular output, no other firm can produce at all—at least not at a reasonable cost. For example, a firm that owns the only quarry in a region is the only firm that can profitably sell gravel to local construction firms. Natural Monopoly. A market has a natural monopoly if one firm can produce the total output of the market at lower cost than two or more firms could. A firm can be a natural monopoly even if it does not have a cost advantage over rivals provided that average cost is lower if only one firm operates. Specifically, if the cost for any firm to produce q is C(q), the condition for a natural monopoly is C(Q) 6 C(q1) + C(q2) + g + C(qn), (9.11) where Q = q1 + q2 + g + qn is the sum of the output of any n firms where n Ú 2 firms. If a firm has economies of scale at all levels of output, its average cost curve falls as output increases for any observed level of output. If all potential firms have the same strictly declining average cost curve, this market is a natural monopoly, as we now illustrate.16 A company that supplies water to homes incurs a high fixed cost, F, to build a plant and connect houses to the plant. The firm’s marginal cost, m, of supplying water is constant, so its marginal cost curve is horizontal and its average cost, AC = m + F/Q, declines as output rises. Figure 9.6 shows such marginal and average cost curves where m = 10 and F = 60. If the market output is 12 units per day, one firm produces that output 15When a firm develops a better production method that provides it with a cost advantage, it is important for the firm to either keep the information secret or obtain a patent, whereby the government protects it from having its innovation imitated. Thus, both secrecy and patents facilitate cost-based monopolies. 16A firm may be a natural monopoly even if its cost curve does not fall at all levels of output. If a U-shaped average cost curve reaches its minimum at 100 units of output, it may be less costly for only one firm to produce an output of 101 units even though average cost is rising at that output. Thus, a cost function with economies of scale everywhere is a sufficient but not a necessary condition for a natural monopoly. 9.4 Causes of Monopoly 295 This natural monopoly has a strictly declining average cost, AC = 10 + 60/Q. AC, MC, $ per unit F IG U RE 9. 6 Natural Monopoly 40 20 AC = 10 + 60/Q 15 10 0 MC = 10 6 12 15 Q, Units per day at an average cost of 15, or a total cost of 180 (= 15 * 12). If two firms each produce 6 units, the average cost is 20 and the cost of producing the market output is 240 (= 20 * 12), which is greater than the cost with a single firm. If the two firms divided total production in any other way, their cost of production would still exceed the cost of a single firm (as the following question asks you to prove). The reason is that the marginal cost per unit is the same no matter how many firms produce, but each additional firm adds a fixed cost, which raises the cost of producing a given quantity. If only one firm provides water, the cost of building a second plant and a second set of pipes is avoided. In an industry with a natural monopoly cost structure, having just one firm is the cheapest way to produce any given output level. Governments often use a natural monopoly argument to justify their granting the right to be a monopoly to public utilities, which provide essential goods or services such as water, gas, electric power, or mail delivery. Q& A 9.4 A firm that delivers Q units of water to households has a total cost of C(Q) = mQ + F. If any entrant would have the same cost, does this market have a natural monopoly? Answer Determine whether costs rise if two firms produce a given quantity. Let q1 be the output of Firm 1 and q2 be the output of Firm 2. The combined cost of these two firms producing Q = q1 + q2 is C(q1) + C(q2) = (mq1 + F) + (mq2 + F) = m(q1 + q2) + 2F = mQ + 2F. If a single firm produces Q, its cost is C(Q) = mQ + F. Thus, the cost of producing any given Q is greater with two firms than with one firm (the condition in Equation 9.11), so this market is a natural monopoly. 296 CHAPTER 9 Monopoly Government Creation of Monopoly Governments have created many monopolies. Sometimes governments own and manage such monopolies. In the United States, as in most countries, first class mail delivery is a government monopoly. Many local governments own and operate public utility monopolies that provide garbage collection, electricity, water, gas, phone services, and other utilities. Barriers to Entry. Frequently governments create monopolies by preventing competing firms from entering a market occupied by an existing incumbent firm. Several countries, such as China, maintain a tobacco monopoly. Similarly, most governments grant patents that limit entry and allow the patent-holding firm to earn a monopoly profit from an invention—a reward for developing the new product that acts as an incentive for research and development. By preventing other firms from entering a market, governments create monopolies. Typically, governments create monopolies either by making it difficult for new firms to obtain a license to operate or by explicitly granting a monopoly right to one firm, thereby excluding other firms. By auctioning a monopoly right to a private firm, a government can capture the future value of monopoly earnings.17 Frequently, firms need government licenses to operate. If one initial incumbent has a license and governments make it difficult for new firms to obtain licenses, the incumbent firm may maintain its monopoly for a substantial period. Until recently, many U.S. cities required that new hospitals or other inpatient facilities demonstrate the need for a new facility to obtain a certificate of need, which allowed them to enter the market. Government grants of monopoly rights have been common for public utilities. Instead of running a public utility itself, a government might give a private sector company the monopoly rights to operate the utility. A government may capture some of the monopoly profits by charging the firm in some way for its monopoly rights. In many countries or other political jurisdictions, such a system is an inducement to bribery as public officials may be bribed by firms seeking monopoly privileges. Governments around the world have privatized many state-owned monopolies in the past several decades. By selling cable television, garbage collection, phone service, towing, and other monopolies to private firms, a government can capture the value of future monopoly earnings today. However, for political or other reasons, governments frequently sell at a lower price that does not capture all future profits. Patents. If an innovating firm cannot prevent imitation by keeping its discoveries secret, it may try to obtain government protection to prevent other firms from duplicating its discovery and entering the market. Most countries provide such protection through patents. A patent is an exclusive right granted to the inventor of a new and useful product, process, substance, or design for a specified length of time. The length of a patent varies across countries, although it is now 20 years in the United States and in most other countries. This right allows the patent holder to be the exclusive seller or user of the new invention.18 Patents often give rise to monopoly, but not always. For example, 17Alternatively, a government could auction the rights to the firm that offers to charge the lowest price, so as to maximize total surplus. 18Owners of patents may sell or grant the right to use a patented process or produce a patented product to other firms. This practice is called licensing. 9.4 Causes of Monopoly 297 although a patent may grant a firm the exclusive right to use a particular process in producing a product, other firms may be able to produce the same product using different processes. In Chapter 16, we discuss the reasons why governments grant patents. M ini-Case Botox Ophthalmologist Dr. Alan Scott turned the deadly poison botulinum toxin into a miracle drug to treat two eye conditions: strabismus, which affects about 4% of children, and blepharospasm, an uncontrollable closure of the eyes. Blepharospasm left about 25,000 Americans functionally blind before Scott’s discovery. His patented drug, Botox, is sold by Allergan, Inc. Dr. Scott has been amused to see several of the unintended beneficiaries of his research at the Academy Awards. Even before it was explicitly approved for cosmetic use, many doctors were injecting Botox into the facial muscles of actors, models, and others to smooth out their wrinkles. (The drug paralyzes the muscles, so those injected with it also lose the ability to frown—and, some would say, to act.) The treatment is only temporary, lasting up to 120 days, so repeated injections are necessary. Allergan had expected to sell $400 million worth of Botox in 2002. However, in April of that year, the U.S. Food and Drug Administration approved the use of Botox for cosmetic purposes, a ruling that allows the company to advertise the drug widely. Allergan had Botox sales of $800 million in 2004 and about $1.8 billion in 2012. Allergan has a near-monopoly in the treatment of wrinkles, although plastic surgery and collagen, Restylane, hyaluronic acids, and other filler injections provide limited competition. Between 2002 and 2004, the number of facelifts dropped 3% to about 114,000 according to the American Society of Plastic Surgeons, while the number of Botox injections skyrocketed 166% to nearly 3 million. Dr. Scott says that he can produce a vial of Botox in his lab for about $25. Allergan then sells the potion to doctors for about $400. Assuming that the firm is setting its price to maximize its short-run profit, we can rearrange Equation 9.10 to determine the elasticity of demand for Botox: ε = - p p - MC = - 400 ≈ -1.067. 400 - 25 Thus, the demand that Allergan faces is only slightly elastic: A 1% increase in price causes quantity to fall by only a little more than 1%. If we assume that the demand curve is linear and that the elasticity of demand is -1.067 at the 2002 monopoly optimum, em (one million vials sold at $400 each, producing revenue of $400 million), then Allergan’s inverse demand function is p = 775 - 375Q. This demand curve (see graph) has a slope of -375 and hits the price axis at $775 and the quantity axis at about 2.07 million vials per year. The corresponding marginal revenue curve, MR = 775 - 750Q, intersects the price axis at $775 and has twice the slope, -750, as the demand curve. p, $ per vial 298 CHAPTER 9 Monopoly At the point where the MR and MC curves intersect, MR = MC. Therefore, 775 775 - 750Q = 25. A≈ $187.5 million 400 B ≈ $375 million 25 0 9.5 We can then solve for the profit-maximizing quantity of 1 million vials per year es and the associated price of $400 per vial. Were the company to sell Botox at a price equal to its Demand marginal cost of $25 (as a competitive industry would), consumer surplus would C ≈ $187.5 million equal areas A + B + C = MR ec MC = AVC $750 million per year. At the higher monopoly price 1 2 2.07 of $400, the consumer surQ, Million vials of Botox per year plus is A = $187.5 million. Compared to the competitive solution, ec, buyers lose consumer surplus of B + C = $562.5 million per year. Part of this loss, B = $375 million per year, is transferred from consumers to Allergan. The rest, C = $187.5 million per year, is the deadweight loss from monopoly pricing. Allergan’s profit is its producer surplus, B, minus its fixed costs. Advertising You can fool all the people all the time if the advertising is right and the budget is big enough. —Joseph E. Levine (film producer) In addition to setting prices or quantities and choosing investments, firms engage in many other strategic actions to boost their profits. One of the most important is advertising. By advertising, a monopoly can shift its demand curve, which may allow it to sell more units at a higher price. In contrast, a competitive firm has no incentive to advertise as it can sell as many units as it wants at the going price without advertising. Advertising is only one way to promote a product. Other promotional activities include providing free samples and using sales agents. Some promotional tactics are subtle. For example, grocery stores place sugary breakfast cereals on lower shelves so that they are at children’s eye level. According to a survey of 27 supermarkets nationwide by the Center for Science in the Public Interest, the average position of 10 child-appealing brands (44% sugar) was on the next-to-bottom shelf, while the average position of 10 adult brands (10% sugar) was on the next-to-top shelf. A monopoly advertises to raise its profit. A successful advertising campaign shifts the market demand curve by changing consumers’ tastes or informing them about new products. The monopoly may be able to change the tastes of some consumers 9.5 Advertising 299 by telling them that a famous athlete or performer uses the product. Children and teenagers are frequently the targets of such advertising. If the advertising convinces some consumers that they can’t live without the product, the monopoly’s demand curve may shift outward and become less elastic at the new equilibrium, at which the firm charges a higher price for its product. If a firm informs potential consumers about a new use for the product, the demand curve shifts to the right. For example, a 1927 Heinz advertisement suggested that putting its baked beans on toast was a good way to eat beans for breakfast as well as dinner. By so doing, it created a British national dish and shifted the demand curve for its product to the right. Deciding Whether to Advertise I have always believed that writing advertisements is the second most profitable form of writing. The first, of course, is ransom notes. . . . —Philip Dusenberry (advertising executive) Even if advertising succeeds in shifting demand, it may not pay for the firm to advertise. If advertising shifts demand outward or makes it less elastic, the firm’s gross profit, ignoring the cost of advertising, must rise. The firm undertakes this advertising campaign, however, only if it expects its net profit (gross profit minus the cost of advertising) to increase. We illustrate a monopoly’s decision making about advertising in Figure 9.7. If the monopoly does not advertise, it faces the demand curve D1. If it advertises, its demand curve shifts from D1 to D2. The monopoly’s marginal cost, MC, is constant and equals its average cost, AC. Before advertising, the monopoly chooses its output, Q1, where its marginal cost hits its marginal revenue curve, MR1, that corresponds to demand curve, D1. The profit-maximizing equilibrium is e1, and the monopoly charges a price of p1. The monopoly’s profit, π1, is a box whose height is the difference between the price and the average cost and whose length is the quantity, Q1. After its advertising campaign shifts its demand curve to D2, the monopoly chooses a higher quantity, Q2 (7 Q1), where the MR2 and MC curves intersect. In this new equilibrium, e2, the monopoly charges p2. Despite this higher price, the monopoly sells more units after advertising because of the outward shift of its demand curve. As a consequence, the monopoly’s gross profit rises. Its new gross profit is the rectangle π1 + B, where the height of the rectangle is the new price minus the average cost, and the length is the quantity, Q2. Thus, the benefit, B, to the monopoly from advertising at this level is the increase in its gross profit. If its cost of advertising is less than B, its net profit rises, and it pays for the monopoly to advertise at this level rather than not to advertise at all. How Much to Advertise The man who stops advertising to save money is like the man who stops the clock to save time. How much should a monopoly advertise to maximize its net profit? The rule for setting the profit-maximizing amount of advertising is the same as that for setting the profit-maximizing amount of output: Set advertising or quantity where the marginal benefit (the extra gross profit from one more unit of advertising or the marginal revenue from one more unit of output) equals its marginal cost. 300 CHAPTER 9 Monopoly F IG U RE 9. 7 Advertising Thus, if the cost of advertising is less than the benefits from advertising, B, the monopoly’s net profit (gross profit minus the cost of advertising) rises. p, $ per unit If the monopoly does not advertise, its demand curve is D1. At its actual level of advertising, its demand curve is D2. Advertising increases the monopoly’s gross profit (ignoring the cost of advertising) from π1 to π2 = π1 + B. p2 p1 e2 B e1 π1 MC = AC MR1 Q1 Q2 MR 2 D1 D2 Q, Units per year Consider what happens if the monopoly raises or lowers its advertising expenditures by $1, which is its marginal cost of an additional unit of advertising. If a monopoly spends one more dollar on advertising—its marginal cost of advertising— and its gross profit rises by more than $1, its net profit rises, so the extra advertising pays. A profit-maximizing monopoly keeps increasing its advertising until the last dollar of advertising raises its gross profit by exactly $1. If it were to advertise more, its profit would fall. Using Calculus Optimal Advertising We can derive this marginal rule for optimal advertising using calculus. A monopoly’s inverse demand function is p = p(Q, A), which says that the price it must charge to clear the market depends on the number of units it chooses to sell, Q, and on the level of its advertising, A. As a result, the firm’s revenue function is R(Q, A) = p(Q, A)Q. The firm’s cost function is C(Q) + A, where C(Q) is the cost of manufacturing Q units and A is the cost of advertising, because each unit of advertising costs $1 (by choosing the units of measure appropriately). The monopoly’s profit is π(Q, A) = R(Q, A) - C(Q) - A. (9.12) 9.5 Advertising 301 The monopoly maximizes its profit by choosing Q and A. Its first-order conditions to maximize its profit are found by partially differentiating the profit function in Equation 9.12 with respect to Q and A in turn: 0π(Q, A) 0R(Q, A) dC(Q) = = 0, 0Q 0Q dQ (9.13) 0π(Q, A) 0R(Q, A) = - 1 = 0. 0A 0A (9.14) The profit-maximizing output and advertising levels are the Q and A that simultaneously satisfy Equations 9.13 and 9.14. Equation 9.13 says that the monopoly should set its output so that the marginal revenue from one more unit of output, 0R/0Q, equals the marginal cost, dC/dQ, which is the same condition that we previously derived before considering advertising. According to Equation 9.14, the monopoly should advertise to the point where its marginal revenue or marginal benefit from the last unit of advertising, 0R/0A, equals the marginal cost of the last unit of advertising, $1. Q&A 9.5 A monopoly’s inverse demand function is p = 800 - 4Q + 0.2A0.5, where Q is its quantity, p is its price, and A is the level of advertising. Its marginal cost of production is 2, and its cost of a unit of advertising is 1. What are the firm’s profit-maximizing price, quantity, and level of advertising? Answer 1. Write the firm’s profit function using its inverse demand function. The monopoly’s profit is π = (800 - 4Q + 0.2A0.5)Q - 2Q - A (9.15) = 798Q - 4Q2 + 0.2A0.5Q - A. 2. Set the partial derivatives of the profit function in Equation 9.15 with respect to Q and A to zero to obtain the equations that determine the profit-maximizing levels, as in Equations 9.13 and 9.14. The first-order conditions are 0π = 798 - 8Q + 0.2A0.5 = 0, 0Q (9.16) 0π = 0.1A-0.5Q - 1 = 0. 0A (9.17) 3. Solve Equations 9.16 and 9.17 for the profit-maximizing levels of Q and A. We can rearrange Equation 9.17 to show that A0.5 = 0.1Q. Substituting this expression into the Equation 9.16, we find that 798 - 8Q + 0.02Q = 0, or Q = 100. Thus, A0.5 = 0.1Q = 10, so A = 100. M ini-Case Super Bowl Commercials Super Bowl commercials are the most expensive commercials on U.S. television. A 30-second spot during the Super Bowl averaged over $3.8 million in 2013. A high price for these commercials is not surprising because the cost of commercials generally increases with the number of viewers (eyeballs in industry jargon), 302 CHAPTER 9 Monopoly and the Super Bowl is the most widely watched show, with over 108 million viewers in 2013. What is surprising is that Super Bowl advertising costs 2.5 times as much per viewer as other TV commercials. However, a Super Bowl commercial is much more likely to influence viewers than commercials on other shows. The Super Bowl is not only a premier sports event; it showcases the most memorable commercials of the year, such as Apple’s classic 1984 Macintosh ad, which is still discussed today. Indeed, many Super Bowl viewers are not even football fans—they watch to see these superior ads. Moreover, Super Bowl commercials receive extra exposure because these ads often go viral on the Internet. Given that Super Bowl ads are more likely to be remembered by viewers, are these commercials worth the extra price? Obviously many advertisers believe so, as their demand for these ads has bid up the price. Kim (2011) found that immediately after a Super Bowl commercial airs, the advertising firm’s stock value rises. Thus, investors apparently believe that Super Bowl commercials raise a firm’s profits despite the high cost of the commercial. Ho et al. (2009) found that, for the typical movie with a substantial advertising budget, a Super Bowl commercial advertising the movie raises theater revenues by more than the same expenditure on other television advertising. They also concluded that movie firms’ advertising during the Super Bowl was at (or close to) the profit-maximizing amount. 9.6 Networks, Dynamics, and Behavioral Economics We have examined how a monopoly behaves in the current period, ignoring the future. For many markets, such an analysis is appropriate as each period can be treated separately. However, in some markets, decisions today affect demand or cost in a future period, creating a need for a dynamic analysis, in which managers explicitly consider relationships between different periods. In such markets, the monopoly may maximize its long-run profit by making a decision today that does not maximize its short-run profit. For example, frequently a firm introduces a new product—such as a new type of candy bar—by initially charging a low price or giving away free samples to generate word-of-mouth publicity or to let customers learn about its quality in hopes of getting their future business. We now consider an important reason why consumers’ demand in the future may depend on a monopoly’s actions in the present. Network Externalities The number of customers a firm has today may affect the demand curve it faces in the future. A good has a network externality if one person’s demand depends on the consumption of the good by others.19 If a good has a positive network externality, its value to a consumer grows as the number of units sold increases. 19In Chapter 16, we discuss the more general case of an externality, which occurs when a person’s well-being or a firm’s production capability is directly affected by the actions of other consumers or firms rather than indirectly through changes in prices. The following discussion on network externalities is based on Leibenstein (1950), Rohlfs (1974), Katz and Shapiro (1994), Economides (1996), Shapiro and Varian (1999), and Rohlfs (2001). 9.6 Networks, Dynamics, and Behavioral Economics 303 When a firm introduces a new good with a network externality, it faces a chickenand-egg problem: It can’t get Max to buy the good unless Sofia will buy it, but it can’t get Sofia to buy it unless Max will. The firm wants its customers to coordinate or to make their purchase decisions simultaneously. The telephone provides a classic example of a positive network externality. When the phone was introduced, potential adopters had no reason to get phone service unless their family and friends did. Why buy a phone if there’s no one to call? For Bell’s phone network to succeed, it had to achieve a critical mass of users— enough adopters that others wanted to join. Had it failed to achieve this critical mass, demand would have withered and the network would have died. Similarly, the market for fax machines grew very slowly until a critical mass was achieved where many firms had them. Direct Size Effects. Many industries exhibit positive network externalities where the customer gets a direct benefit from a larger network. The larger an automated teller machine (ATM) network, such as the Plus network, the greater the odds that you will find an ATM when you want one, so the more likely it is that you will want to use that network. The more people who use a particular computer program, the more attractive it is to someone who wants to exchange files with other users. Indirect Effects. In some markets, positive network externalities are indirect and stem from complementary goods that are offered when a product has a critical mass of users. The more applications (apps) available for a smart phone, the more people want to buy that smart phone. However, many of these extra apps will be written only if a critical mass of customers buys the smart phone. Similarly, the more people who drive diesel-powered cars, the more likely it is that gas stations will sell diesel fuel; and the more stations that sell the fuel, the more likely it is that someone will want to drive a diesel car. As a final example, once a critical mass of customers had broadband Internet service, more services provided downloadable music and movies and more high-definition Web pages become available. Once those popular apps appeared, more people signed up for broadband service. Network Externalities and Behavioral Economics The direct effect of network externalities depends on the size of the network, because customers want to interact with each other. However, sometimes consumers’ behavior depends on beliefs or tastes that can be explained by psychological and sociological theories, which economists study in behavioral economics (Chapter 4). One such explanation for a direct network externality effect is based on consumer attitudes toward other consumers. Harvey Leibenstein (1950) suggested that consumers sometimes want a good because “everyone else has it.” A fad or other popularity-based explanation for a positive network externality is called a bandwagon effect: A person places greater value on a good as more and more other people possess it.20 The success of the iPad today may be partially due to its early popularity. The opposite, negative network externality is called a snob effect: A person places greater value on a good as fewer and fewer other people possess it. Some people prefer an original painting by an unknown artist to a lithograph by a star because no 20Jargon alert: Some economists use bandwagon effect to mean any positive network externality—not just those that are based on popularity. 304 CHAPTER 9 Monopoly one else can possess that painting. (As Yogi Berra is reported to have said, “Nobody goes there anymore; it’s too crowded.”) Network Externalities as an Explanation for Monopolies Because of the need for a critical mass of customers in a market with a positive network externality, we sometimes see only one large firm surviving. Visa’s ad campaign tells consumers that Visa cards are accepted “everywhere you want to be,” including places that “don’t take American Express.” One could view its ad campaign as an attempt to convince consumers that its card has a critical mass and therefore that everyone should carry it. The Windows operating system largely dominates the market—not because it is technically superior to Apple’s operating system or Linux—but because it has a critical mass of users. Consequently, a developer can earn more producing software that works with Windows than with other operating systems, and the larger number of software programs makes Windows increasingly attractive to users. But having obtained a monopoly, a firm does not necessarily keep it. History is filled with examples where one product knocks off another: “The king is dead; long live the king.” Google replaced Yahoo! as the predominant search engine. Microsoft’s Explorer displaced Netscape as the big-dog browser, followed in turn by Google Chrome. Levi Strauss is no longer the fashion leader among the jeans set. Mini-Case Critical Mass and eBay In recent years, many people have argued that natural monopolies emerge after brief periods of Internet competition. A typical Web business requires a large up-front fixed cost—primarily for development and promotion—but has a relatively low marginal cost. Thus, Internet start-ups typically have downward-sloping average cost-per-user curves. Which of the actual or potential firms with decreasing average costs will dominate and become a natural monopoly?21 In the early years, eBay’s online auction site, which started in 1995, faced competition from a variety of other Internet sites, including one created in 1998 by then mighty Yahoo!. At the time, many commentators correctly predicted that whichever auction site first achieved a critical mass of users would drive the other sites out of business. Indeed, most of these alternative sites died or faded into obscurity. For example, Yahoo! Auctions closed its U.K. and Irish sites in 2002, its Australian site in 2003, its U.S. and Canadian sites in 2007, and its Singapore site in 2008 (however, as of early 2013 its Hong Kong, Taiwanese, and Japanese sites continue to operate). Apparently the convenience of having one site where virtually all buyers and sellers congregate is valuable to consumers. Such a site lowers buyers’ search 21If Internet sites provide differentiated products (Chapter 11), then several sites may coexist even though average costs are strictly decreasing. In 2007, commentators were predicting the emergence of natural monopolies in social networks such as MySpace, which has since lost its dominance. However, whether a single social network can dominate for long is debatable given frequent innovations. Even if MySpace or Facebook temporarily dominates other similar sites, it may eventually lose ground to Web businesses with new models, such as Twitter. 9.6 Networks, Dynamics, and Behavioral Economics 305 costs and allows the creation of useful reputation systems for providing user feedback (Brown and Morgan, 2006). These benefits attract more buyers, thereby raising the prices that sellers can expect to receive, which in turn attracts more sellers. Brown and Morgan (2010) found that, prior to the demise of the U.S. Yahoo! Auction site, the same type of items attracted an average of two additional bidders on eBay and, consequently, the prices on eBay were consistently 20% to 70% percent higher than Yahoo! prices—making eBay more attractive than Yahoo! to sellers. Ma nagerial I mplication Introductory Prices Managerial Solution Brand-Name and Generic Drugs Managers should consider initially selling a new product at a low introductory price to obtain a critical mass. By doing so, the manager maximizes long-run profit but not short-run profit. Suppose that a monopoly sells its good—say, root-beer-scented jeans—for only two periods (after that, the demand goes to zero as a new craze hits the market). If the monopoly sells less than a critical quantity of output, Q, in the first period, then its second-period demand curve lies close to the price axis. However, if the good is a success in the first period—at least Q units are sold—the second-period demand curve shifts substantially to the right. If the monopoly maximizes its short-run profit in the first period, it charges p* and sells Q* units, which is fewer than Q. To sell Q units, it would have to lower its first-period price below p*, which would reduce its first-period profit from π* to π. In the second period, the monopoly maximizes its profit given its second-period demand curve. If the monopoly sold only Q* units in the first period, it earns a relatively low second-period profit of πl. However, if it sells Q units in the first period, it makes a relatively high second-period profit, πh. Should the monopoly charge a low introductory price in the first period? Its objective is to maximize its long-run profit: the sum of its profit in the two periods.22 If the firm has a critical mass in the second period, its extra profit is πh - πl. To obtain this critical mass by charging a low introductory price in the first period, it lowers its first-period profit by π* - π. Thus, a manager should charge a low introductory price in the first period if the first-period loss is less than the extra profit in the second period. This policy is apparently profitable for many firms: A 2012 Google search found 103 million Web pages touting an introductory price. When generic drugs enter the market after the patent on a brand-name drug expires, the demand curve facing the brand-name firm shifts toward the origin (to the left). Why do the managers of many brand-name drug companies raise their prices after generic rivals enter the market? The reason is that the demand curve not only shifts to the left but it rotates so that it is less elastic at the original price. 22Firms place lower value on profit in the future than profit today (Chapter 7). However, for simplicity, we assume that the monopoly places equal value on profit in either period. CHAPTER 9 Monopoly The price the brand-name firm sets depends on the elasticity of demand. When the firm has a patent monopoly, it faces demand curve D1 in the figure. Its monopoly optimum, e1, is determined by the intersection of the corresponding marginal revenue curve MR1 and the marginal cost curve. (Because it is twice as steeply sloped as the demand curve, MR1 intersects the MC curve at Q1, while the demand curve D1 intersects the MC curve at 2Q1.) The monopoly sells the Q1 units at a price of p1. p, $ per unit 306 e2 p2 e1 p1 MC MR 2 Q2 MR 1 Q1 2Q2 D1 D2 2Q1 Q, Units per day After the generic drugs enter the market, the linear demand curve facing the original patent holder shifts left to D2 and becomes steeper and less elastic at the original price. The firm now maximizes its profit at e2, where the quantity, Q2, is smaller than Q1 because D2 lies to the left of D1. However, the new price p2 is higher than the initial price p1 because the D2 demand curve is less elastic at the new optimum quantity Q2 than is the D1 curve at Q1. Why might the demand curve rotate and become less elastic at the initial price? One explanation is that the brand-name firm has two types of consumers with different elasticities of demand who differ in their willingness to switch to a generic. One group of consumers is relatively price-sensitive and will switch to the lower-priced generics. However, the brand-name drug remains the monopoly supplier to the remaining brand-loyal customers whose demand is less elastic than that of the price-sensitive consumers. These loyal customers prefer the brand-name drug because they are more comfortable with a familiar product, worry that new products may be substandard, or fear that differences in the inactive ingredients might affect them. Older customers are less likely to switch brands than younger people. A survey of the American Association of Retired Persons found that people aged 65 and older were 15% less likely than people aged 45 to 64 to request generic versions of a drug from their doctor or pharmacist. Similarly, patients with generous insurance plans may be more likely to pay for expensive drugs (if their insurer permits) than customers without insurance. Questions 307 S U MMARY 1. Monopoly Profit Maximization. Like any firm, a monopoly—a single seller—maximizes its profit by setting its output so that its marginal revenue equals its marginal cost. The monopoly makes a positive profit if its average cost is less than the price at the profit-maximizing output. 2. Market Power. Market power is the ability of cost function). Many, if not most, monopolies are created by governments, which prevent other firms from entering the markets. One important barrier to entry is a patent, which gives the inventor of a new product or process the exclusive right to sell the product or use the process for 20 years in most countries. a firm to significantly affect the market price. The extent of a firm’s market power depends on the shape of the demand curve. The more elastic the demand curve at the point where the firm is producing, the lower the markup of price over marginal cost. 5. Advertising. A monopoly advertises or engages 3. Market Failure Due to Monopoly Pricing. externality so that its value to a consumer grows as the number of units sold increases, then current sales affect a monopoly’s future demand curve. A monopoly may maximize its profit over time by setting a low introductory price in the first period in which it sells the good and then later raising its price as its product’s popularity ensures large future sales at a higher price. Consequently, the monopoly is not maximizing its short-run profit in the first period but is maximizing the sum of its profits over all periods. Behavioral economics provides an explanation for some network externalities, such as bandwagon effects and snob effects. Because a monopoly’s price is above its marginal cost, too little output is produced, and society suffers a deadweight loss. The monopoly makes higher profit than it would if it acted as a price taker. Consumers are worse off, buying less output at a higher price. 4. Causes of Monopoly. A firm may be a monopoly if it has lower operating costs than rivals, due to reasons such as from superior knowledge or control of a key input. A market may also have a natural monopoly if one firm can produce the market output at lower average cost than can a larger number of firms (even if all firms have the same in other promotional activity to shift its demand curve to the right or make it less elastic so as to raise its profit net of its advertising expenses. 6. Networks, Dynamics, and Behavioral Economics. If a good has a positive network Q U E S T ION S All exercises are available on MyEconLab; * = answer at the back of this book; C = use of calculus may be necessary. 1. Monopoly Profit Maximization 1.1. If the inverse demand function is p = 300 - 3Q, what is the marginal revenue function? Draw the demand and marginal revenue curves. At what quantities do the demand and marginal revenue lines hit the quantity axis? (Hint: See Q&A 9.1.) 1.2. If the inverse demand curve a monopoly faces is p = 10Q -0.5, what is the firm’s marginal revenue curve? C (Hint: See Q&A 9.1.) *1.3. If the inverse demand function is p = 500 - 10Q, what is the elasticity of demand and revenue at Q = 10? 1.4. Does it affect a monopoly’s profit if it chooses price or quantity (assuming it chooses them optimally)? Why can’t a monopoly choose both price and quantity? 1.5. For the monopoly in Figure 9.3 at what quantity is its revenue maximized? (Hint: At the quantity where the revenue function reaches its peak, the slope of the revenue function is zero. That is, MR = 0.) Why is revenue maximized at a larger quantity than profit? Modify panel b of Figure 9.3 to show the revenue curve. 1.6. Are major-league baseball clubs profit-maximizing monopolies? Some observers of this market have contended that baseball club owners want to maximize attendance or revenue. Alexander (2001) says that one test of whether a firm is a profit-maximizing monopoly is to check whether the firm is operating in the elastic portion of its demand curve (which he finds is true). Why is that a relevant test? What would the elasticity be if a baseball club were maximizing revenue? 1.7. Using a graph, show under what condition the monopoly operates—does not shut down—in the long run. Discuss your result in terms of the demand curve and the average cost curve at the profitmaximizing quantity. 308 CHAPTER 9 Monopoly 1.8. Why might a monopoly operate in any part (downward sloping, flat, upward sloping) of its longrun average cost curve, but a competitive firm will operate only at the bottom or in the upward-sloping section? 94.95¢ per stamp, or a 216% markup). Stamps.com keeps the extra beyond the 44¢ it pays the USPS. What is the firm’s Lerner Index? If Stamps.com is a profit-maximizing monopoly, what elasticity of demand does it face for a customized stamp? 1.9. AT&T Inc., the large U.S. phone company and the one-time monopoly, left the payphone business at the beginning of 2009 because people were switching to wireless phones. U.S. consumers owning cellphones reached 80% by 2007 and 86% by 2012 according to the Pew Research Center. Consequently, the number of payphones fell from 2.6 million at the peak in 1998 to 1 million in 2006 (Crayton Harrison, “AT&T to Disconnect Pay-Phone Business After 129 Years,” Bloomberg.com, December 3, 2007). (Where will Clark Kent go to change into Superman now?) Use graphs to explain why a monopoly exits a market when its demand curve shifts to the left. 2.5. According to the California Nurses Association, Tenet Healthcare hospitals marked up drugs substantially. At Tenet’s Sierra Vista Regional Medical Center, drug prices were 1,840.80% of the hospital’s costs (Chuck Squatriglia and Tyche Hendricks, “Tenet Hiked Drug Prices, Study Finds More Than Double U.S. Average,” San Francisco Chronicle, November 24, 2002: A1, A10). Assuming Tenet was maximizing its profit, what was the elasticity of demand that Tenet believed it faced? What was its Lerner Index for drugs? *1.10. The inverse demand function a monopoly faces is p = 100 - Q. The firm’s cost curve is C(Q) = 10 + 5Q. What is the profit-maximizing solution? How does your answer change if C(Q) = 100 + 5Q? 1.11. The inverse demand function a monopoly faces is p = 10Q -0.5 (Hint: See Question 1.2). The firm’s cost curve is C(Q) = 5Q. What is the profit-maximizing solution? C 1.12. Show that after a shift in the demand curve, a monopoly’s price may remain constant but its output may rise. 2. Market Power 2.1. Why is the ratio of the monopoly’s price to its marginal cost, p/MC, larger if the demand curve is less elastic at the optimum quantity? Can the demand curve be inelastic at that quantity? 2.2. When will a monopoly set its price equal to its marginal cost? 2.3. At the profit-maximizing quantity in Figure 9.2, what is the elasticity of demand? What is the Lerner Index? (Hint: Can you determine the answers to these questions using only the price and marginal cost information from the figure?) 2.4. The U.S. Postal Service (USPS) has a constitutionally guaranteed monopoly on first-class mail. In 2012, it charged 44¢ for a stamp, which was not the profit-maximizing price—the USPS’s goal, allegedly, is to break even rather than to turn a profit. Following the postal services in Australia, Britain, Canada, Switzerland, and Ireland, the USPS allowed Stamps.com to sell a sheet of twenty 44¢ stamps with a photo of your dog, your mommy, or whatever image you want for $18.99 (that’s 2.6. Using the information in Q&A 9.2, calculate the elasticity of demand faced by Apple at the profit maximizing price and quantity using the inverse demand function. *2.7. In 2009, the price of Amazon’s Kindle 2 was $359, while iSuppli estimated that its marginal cost was $159. What was Amazon’s Lerner Index? What elasticity of demand did it face if it was engaging in short-run profit maximization? 2.8. When the iPod was introduced, Apple’s constant marginal cost of producing its top-of-the-line iPod was $200 (iSuppli), its fixed cost was approximately $736 million, and we estimate that its inverse demand function was p = 600 - 25Q, where Q is units measured in millions. What was Apple’s average cost function? Assuming that Apple was maximizing its short-run monopoly profit, what was its marginal revenue function? What were its profit-maximizing price and quantity, profit, and Lerner Index? What was the elasticity of demand at the profit-maximizing level? Show Apple’s profitmaximizing solution in a figure. (Hint: See Q&A 9.2.) 3. Market Failure Due to Monopoly Pricing 3.1. A monopoly has a constant marginal cost of production of $1 per unit and a fixed cost of $10. Draw the firm’s MC, AVC, and AC curves. Add a downward-sloping demand curve, and show the profit-maximizing quantity and price. Indicate the profit as an area on your diagram. Show the deadweight loss. 3.2. A monopoly has an inverse demand function given by p = 120 - Q and a constant marginal cost of 10. Calculate the deadweight loss if the monopoly charges the profit-maximizing price. 3.3. What is the effect of a lump-sum tax (which is like an additional fixed cost) on a monopoly? (Hint: Consider the possibility that the firm may shut down, and see Q&A 9.3.) Questions 3.4. If the inverse demand function is p = 120 - Q and the marginal cost is constant at 10, how does charging the monopoly a specific tax of τ = 10 per unit affect price and quantity and the welfare of consumers, the monopoly, and society (where society’s welfare includes the tax revenue)? What is the incidence of the tax on consumers? (Hint: See Q&A 9.3.) *3.5. Show mathematically that a monopoly may raise the price to consumers by more than a specific tax imposed on it. (Hint: Consider a monopoly facing a constant-elasticity demand curve and a constant marginal cost, m.) C 4. Causes of Monopoly *4.1. Can a firm be a natural monopoly if it has a U-shaped average cost curve? Why or why not? (Hint: See Q&A 9.4.) 4.2. Can a firm operating in the upward-sloping portion of its average cost curve be a natural monopoly? Explain. (Hint: See Q&A 9.4.) 4.3. Once the copyright runs out on a book or music, it can legally be placed on the Internet for anyone to download. In 1998 the U.S. Congress extended the copyright law to 95 years after the original publication. But the copyright holds for only 50 years in Australia and 70 years in the European Union. Thus, an Australian website could post Gone With the Wind, a 1936 novel, or Elvis Presley’s 1954 single “That’s All Right,” while a U.S. site could not. Obviously, this legal nicety won’t stop U.S. fans from downloading from Australian or European sites. Discuss how limiting the length of a copyright would affect the pricing used by the publisher of a novel. 4.4. In the “Botox” Mini-Case, consumer surplus, triangle A, equals the deadweight loss, triangle C. Show that this equality is a result of the linear demand and constant marginal cost assumptions. 4.5. Based on the information in the “Botox” Mini-Case, what would happen to the equilibrium price and quantity if the government had set a price ceiling of $200 per vial of Botox? What welfare effects would such a policy have? 5. Advertising 5.1. Using a graph, explain why a firm might not want to spend money on advertising, even if such an expenditure would shift the firm’s demand curve to the right. *5.2. A monopoly’s inverse demand function is p = 100 - Q + (5A - A2)/Q, where Q is its quantity, p is its price, and A is the level of advertising. Its marginal cost of production is constant at 10, and its cost of a unit of advertising is 1. What are the 309 firm’s profit-maximizing price, quantity, and level of advertising? (Hint: See Q&A 9.5.) C 5.3. A monopoly’s inverse demand function is p = Q -0.25A0.5, where Q is its quantity, p is its price, and A is the level of advertising. Its constant marginal and average cost of production is 6, and its cost of a unit of advertising is 0.25. What are the firm’s profit-maximizing price, quantity, and level of advertising? (Hint: See Q&A 9.5.) C 5.4. Why are newsstand prices higher than subscription prices for an issue of a magazine? 5.5. Canada subsidizes Canadian magazines to offset the invasion of foreign (primarily U.S.) magazines, which take 90% of the country’s sales. The Canada Magazine Fund provides a lump-sum subsidy to various magazines to “maintain a Canadian presence against the overwhelming presence of foreign magazines.” Eligibility is based on high levels of investment in Canadian editorial content and reliance on advertising revenues. What effect will a lump-sum subsidy have on the number of subscriptions sold? 5.6. Use a diagram similar to Figure 9.7 to illustrate the effect of social media on the demand for Super Bowl commercials. (Hint: See the “Super Bowl Commercials” Mini-Case.) 6. Networks, Dynamics, and Behavioral Economics 6.1. A monopoly chocolate manufacturer faces two types of consumers. The larger group, the hoi polloi, loves desserts and has a relatively flat, linear demand curve for chocolate. The smaller group, the snobs, is interested in buying chocolate only if the hoi polloi do not buy it. Given that the hoi polloi do not buy the chocolate, the snobs have a relatively steep, linear demand curve. Show the monopoly’s possible outcomes—high price, low quantity; low price, high quantity—and explain the condition under which the monopoly chooses to cater to the snobs rather than to the hoi polloi. *6.2. A monopoly produces a good with a network externality at a constant marginal and average cost of 2. In the first period, its inverse demand function is p = 10 - Q. In the second period, its demand is p = 10 - Q unless it sells at least Q = 8 units in the first period. If it meets or exceeds this target, then the demand curve rotates out by α (it sells α times as many units for any given price), so that its inverse demand curve is p = 10 - Q/α. The monopoly knows that it can sell no output after the second period. The monopoly’s objective is to maximize the sum of its profits over the two periods. In the first period, should the monopoly set the output that 310 CHAPTER 9 Monopoly maximizes its profit in that period? How does your answer depend on α? C 7. Managerial Problem 7.1. Under what circumstances will a drug company charge more for its drug after its patent expires? 7.2. Does the Managerial Solution change if the entry of the generic causes a parallel shift to the left of the patent monopoly’s linear demand curve? 7.3. Proposals to reduce patent length for drugs are sometimes made, but some critics argue that such a change would result in even higher prices during the patent period as companies would need to recover drug development costs more quickly. Is this argument valid if drug companies maximize profit? 8. Spreadsheet Exercises 8.1. A monopoly faces the inverse demand function: p = 100 - 2Q, with the corresponding marginal revenue function, MR = 100 - 4Q. The firm’s total cost of production is C = 50 + 10Q + 3Q2, with a corresponding marginal cost of MC = 10 + 6Q. a. Create a spreadsheet for Q = 1, 2, 3, c , 15. Using the MR = MC rule, determine the profit-maximizing output and price for the firm and the consequent level of profit. b. Calculate the Lerner Index of monopoly power for each output level and verify its relationship with the value of the price elasticity of demand (ε) at the profit-maximizing level of output. c. Now suppose that a specific tax of 20 per unit is imposed on the monopoly. What is the effect on the monopoly’s profit-maximizing price? 8.2. A firm’s demand function is Q = 110 - p + 2A0.5, where A is the amount of advertising undertaken by the firm and the price of advertising is one. The firm’s cost of production is C = 50 + 10Q + 2Q2. The government imposes a binding price control at $135. Use Excel to determine the profit-maximizing level of advertising. Try advertising levels that vary in hundreds from 0 to $1,000. Select the most profitable range and try smaller increments within that range. What is the firm’s profit-maximizing advertising level and quantity? Pricing with Market Power 10 Everything is worth what its purchaser will pay for it. —Publilius Syrus (first century B.C.) M anagerial P roblem Sale Prices Because many retail managers use sales—temporarily setting the price below the usual price—some customers pay lower prices than others over time. Grocery stores are particularly likely to put products on sale frequently. In large U.S. supermarkets, a soft drink brand is on sale 94% of the time. Either Coke or Pepsi is on sale half the weeks in a year. Heinz Ketchup controls up to 60% of the U.S. ketchup market, 70% of the Canadian market, and nearly 80% of the U.K. market. In 2012, Heinz sold over 650 million bottles of ketchup in more than 140 countries and had annual sales of more than $1.5 billion. When Heinz goes on sale, switchers—ketchup customers who normally buy whichever brand is least expensive—purchase Heinz rather than the low-price generic ketchup. How can Heinz’s managers design a pattern of sales that maximizes Heinz’s profit by obtaining extra sales from switchers without losing substantial sums by selling to its loyal customers at a discount price? Under what conditions does it pay for Heinz to have a policy of periodic sales? S ales are not the only means that firms use to charge customers different prices. Why are airline fares often substantially less if you book in advance? Why do the spiritualists who live at the Wonewoc Spiritualist Camp give readings for $40 for half an hour, but charge seniors only $35 on Wednesdays?1 Why are some goods, including computers and software, combined and sold as a bundle? To answer these questions, we need to examine how monopolies and other noncompetitive firms set prices. In Chapter 9, we examined how a monopoly maximizes its profit when it uses uniform pricing: charging the same price for every unit sold of a particular good. However, a monopoly can increase its profit if it can use nonuniform pricing, where a firm charges consumers different prices for the same product or charges a single customer a price that depends on the number of units the customer buys. In this 1www.msnbc.msn.com/id/20377308/wid/11915829, August 29, 2007. 311 312 CHAPTER 10 Pricing with Market Power chapter, we analyze nonuniform pricing for monopolies, but similar principles apply to any firm with market power. As we saw in Chapter 9, a monopoly that sets a uniform price sells only to customers who value the good enough to buy it at the monopoly price, and those customers receive some consumer surplus. The monopoly does not sell the good to other customers who value the good at less than the single price, even if those consumers would be willing to pay more than the marginal cost of production. These lost sales cause deadweight loss, which is the foregone value of these potential sales in excess of the cost of producing the good. A firm with market power can earn a higher profit using nonuniform pricing than by setting a uniform price for two reasons. First, the firm captures some or all of the single-price consumer surplus. Second, the firm converts at least some of the single-price deadweight loss into profit by charging a price below the uniform price to some customers who would not purchase at the single-price level. A monopoly that uses nonuniform pricing can lower the price to these otherwise excluded consumers without lowering the price to consumers who are willing to pay higher prices. In this chapter, we examine several types of nonuniform pricing including price discrimination, two-part pricing, bundling, and peak-load pricing. The most common form of nonuniform pricing is price discrimination: charging consumers different prices for the same good based on individual characteristics of consumers, membership in an identifiable subgroup of consumers, or on the quantity purchased by the consumers. For example, for a full-year combination print and online subscription, the Wall Street Journal charges $99.95 to students, who are price sensitive, and $155 to other subscribers, who are less price sensitive. Some firms with market power use other forms of nonuniform pricing to increase profits. A firm may use two-part pricing, where it charges a customer one fee for the right to buy the good and an additional fee for each unit purchased. For example, members of health or golf clubs typically pay an annual fee to belong to the club and then pay an additional amount each time they use the facilities. Similarly, cable television companies often charge a monthly fee for basic service and an additional fee for recent movies. Another type of nonuniform pricing is called bundling, where several products are sold together as a package. For example, many restaurants provide full-course dinners for a fixed price that is less than the sum of the prices charged if the items (appetizer, main dish, and dessert) are ordered separately (à la carte). Finally, some firms use peak-load pricing: charging higher prices in periods of peak demand than at other times. For example, ticket prices for flights from cold northern cities to Hawaii are higher in the winter months when demand is higher than in the summer. Ma in Topics In this chapter, we examine seven main topics 1. Conditions for Price Discrimination: A firm can increase its profit using price discrimination if it has market power, if customers differ in their willingness to pay, if the firm can identify which customers are more price sensitive than others, and if it can prevent customers who pay low prices from reselling to those who pay high prices. 2. Perfect Price Discrimination: If a firm can charge the maximum each customer is willing to pay for each unit of output, the firm captures all potential consumer surplus. 10.1 Conditions for Price Discrimination 313 3. Group Price Discrimination: A firm that lacks the ability to charge each individual a different price may be able to charge different prices to various groups of customers that differ in their willingness to pay for the good. 4. Nonlinear Price Discrimination: A firm may set different prices for large purchases than for small ones, discriminating among consumers by inducing them to self-select the effective price they pay based on the quantity they buy. 5. Two-Part Pricing: By charging consumers a fee for the right to buy a good and then allowing them to purchase as much as they wish at an additional per-unit fee, a firm earns a higher profit than with uniform pricing. 6. Bundling: By selling a combination of different products in a package or bundle, a firm earns a higher profit than by selling the goods or services separately. 7. Peak-Load Pricing: By charging higher prices during periods of peak demand and lower prices at other times, a firm increases its profit. 10.1 Conditions for Price Discrimination We start by studying the most common form of nonuniform pricing, price discrimination, where a firm charges various consumers different prices for a good.2 Why Price Discrimination Pays For almost any good or service, some consumers are willing to pay more than others. A firm that sets a single price faces a trade-off between charging consumers with a high willingness to pay a high price and charging a low enough price to sell to some customers with a lower willingness to pay. As a result, a single-price firm sets an intermediate price. By price discriminating, a firm can partially or entirely avoid this trade-off. As with any kind of nonuniform pricing, price discrimination increases profit above the uniform pricing level through two channels. Price discrimination can extract additional consumer surplus from consumers who place a high value on the good and can simultaneously sell to new customers who would not be willing to pay the profit-maximizing uniform price. We use a pair of extreme examples to illustrate these two benefits of price discrimination to firms—capturing more of the consumer surplus and selling to more customers. Suppose that the only movie theater in town has two types of patrons: college students and senior citizens. College students see the Saturday night movie if the price is $20 or less, and senior citizens attend if the price is $10 or less. Thus, college students have a willingness to pay of $20 and senior citizens have a willingness to pay of $10. For simplicity, we assume that the theater incurs no cost when showing the movie, so profit is the same as revenue. We also assume that the theater is large enough to hold all potential customers, so the marginal cost of admitting one more customer is zero. Table 10.1 shows how pricing affects the theater’s profit. 2Price discrimination is legal in the United States unless it harms competition between firms, as specified in the Robinson-Patman Act. 314 CHAPTER 10 Pricing with Market Power T A BLE 1 0 .1 Theater Profits Based on the Pricing Method Used (a) No Extra Customers from Price Discrimination Profit from 10 College Students Profit from 20 Senior Citizens Total Profit Uniform, $10 $100 $200 $300 Uniform, $20 $200 $0 $200 Price discrimination* $200 $200 $400 Pricing (b) Extra Customers from Price Discrimination Profit from 10 College Students Profit from 5 Senior Citizens Total Profit Uniform, $10 $100 $50 $150 Uniform, $20 $200 $0 $200 $200 $50 $250 Pricing Price discrimination* *The theater price discriminates by charging college students $20 and senior citizens $10. Notes: College students go to the theater if they are charged no more than $20. Senior citizens are willing to pay up to $10. The theater’s marginal cost for an extra customer is zero. In panel a, the theater potentially has 10 college student and 20 senior citizen customers. If the theater charges everyone $10, its profit is $300 because all 30 potential customers buy a ticket. If it charges $20, the senior citizens do not go to the movie, so the theater makes only $200, receiving $20 each from the 10 college students. Thus, if the theater charges everyone the same price, it maximizes its profit by setting the price at $10. The theater does not want to charge less than $10 because the same number of people go to the movie as go when $10 is charged. Charging between $10 and $20 is less profitable than charging $20 because no extra seniors go and the college students are willing to pay $20. Charging more than $20 results in no customers. If the price is $10, the seniors have no consumer surplus: They pay exactly what seeing the movie is worth to them. Seeing the movie is worth $20 to the college students so, if the price is only $10, each has a consumer surplus of $10, and their combined consumer surplus is $100. If the theater can price discriminate by charging senior citizens $10 and college students $20, its profit increases to $400. Its profit rises because the theater makes $200 from the seniors (the same amount as when it was selling all tickets for $10) but gets an extra $100 from the college students ($10 more from each of the 10 students). By price discriminating, the theater sells the same number of seats but makes more money from the college students, capturing all the consumer surplus they had under uniform pricing. Neither group of customers has any consumer surplus if the theater price discriminates. In panel b, the theater potentially has 10 college student and 5 senior citizen customers. If the theater must charge a single price, it charges $20. Only college students see the movie, so the theater’s profit is $200. (If it charges $10, both students and seniors go to the theater, but its profit is only $150.) If the theater can price discriminate and charge seniors $10 and college students $20, its profit increases to $250. Here the gain from price discrimination comes from selling more tickets (those sold to seniors) and not from making more money on the same number of tickets, as in panel a. The theater earns as much from the students as before and makes more from the seniors, and neither group enjoys any consumer surplus. 10.1 Conditions for Price Discrimination 315 These examples illustrate the two channels through which price discrimination can increase profit: charging some existing customers more or selling extra units. Leslie (1997) found that Broadway theaters in New York increase their profits 5% by price discriminating rather than using uniform prices. In the examples just considered, the movie theater’s ability to increase its profits by price discrimination arises from its ability to segment the market into two groups, students and senior citizens, with different levels of willingness to pay. Mini-Case Disneyland Pricing Disneyland, in southern California, is a well-run operation that rarely misses a trick when it comes to increasing its profit. (Indeed, Disneyland mints money: When you enter the park, you can exchange U.S. currency for Disney dollars, which can be spent only in the park.)3 In 2012, Disneyland charged out-of-state adults $199 for a 3-day park hopper ticket, which admits one to Disneyland and Disney’s California Adventure Park, but charged residents of southern California only $154. This policy of charging locals a discounted price makes sense if visitors are willing to pay more than locals and if Disneyland can prevent locals from selling discounted tickets to nonlocals. Imagine a Midwesterner who’s never been to Disneyland and wants to visit. Travel accounts for most of the trip’s cost, so an extra few dollars for entrance to the park makes little percentage difference in the total cost of the visit and hence does not greatly affect that person’s decision whether to go. In contrast, for a local who has been to Disneyland many times and for whom the entrance price is a larger share of the total cost, a slightly higher entrance fee might prevent a visit.4 Charging both groups the same price is not in Disney’s best interest. If Disney were to charge the higher price to everyone, many locals wouldn’t visit the park. If Disney were to use the lower price for everyone, it would be charging nonresidents much less than they are willing to pay. Thus price discrimination increases Disney’s profit. Which Firms Can Price Discriminate Not all firms can price discriminate. For a firm to price discriminate successfully, three conditions must be met. First, a firm must have market power. Without market power, a firm cannot charge any consumer more than the competitive price. A monopoly, an oligopoly firm, or a monopolistically competitive firm might be able to price discriminate. However, a 3According to www.babycenter.com, it costs $411,214 to raise a child from cradle through college. Parents can cut that total in half, however: They don’t have to take their kids to Disneyland. 4In 2012, a Southern Californian couple, Jeff Reitz and Tonya Mickesh, were out of work, so they decided to cheer themselves up by using their annual passes to visit Disneyland 366 days that year (a leap year). 316 CHAPTER 10 Pricing with Market Power perfectly competitive firm cannot price discriminate because it must sell its product at the given market price. Second, for a firm to profitably discriminate, groups of consumers or individual consumers must have demand curves that differ, and the firm must be able to identify how its consumers’ demand curves differ. The movie theater knows that college students and senior citizens differ in their willingness to pay for a ticket, and Disneyland knows that tourists and local residents differ in their willingness to pay for admission. In both cases, the firms can identify members of these two groups by using driver’s licenses or other forms of identification. Similarly, if a firm knows that each individual’s demand curve slopes downward, it may charge each customer a higher price for the first unit of a good than for subsequent units. Third, a firm must be able to prevent or limit resale. The price-discriminating firm must be able to prevent consumers who buy the good at low prices from reselling the good to customers who would otherwise pay high prices. Price discrimination doesn’t work if resale is easy because the firm would be able to make only low-price sales. A movie theater can charge different prices for different groups of customers because those customers normally enter the theater as soon as they buy their tickets, and therefore they do not have time to resell them. For events that sell tickets in advance, other methods can be used to prevent resale, such as having different colors for children’s tickets and adults’ tickets. The first two conditions—market power and the ability to identify groups with different price sensitivities—are present in many markets. Usually, the biggest obstacle to price discrimination is a firm’s inability to prevent resale. Ma nagerial I mplication Preventing Resale In some industries, preventing resale is easier than in others. In industries where resale is initially easy, managers can act to make resale more costly. Resale is difficult or impossible for most services. If a plumber charges you less than your neighbor for fixing a clogged water pipe, you cannot make a deal with your neighbor to resell this service. Even for physical goods, resale is difficult when transaction costs are high. The higher the transaction costs a consumer must incur to resell a good, the less likely resale becomes. Suppose that you are able to buy a 50-pound bag of cement (which, in addition to being heavy, is also dusty) for $1 less than the usual price. Would you take the time and trouble to buy the cement and seek a buyer willing to pay an extra dollar, or would the transaction costs be prohibitive? The more valuable a product is and the more widely consumed it is, the more likely it is that transaction costs are low enough to allow resale. Some firms act to raise transaction costs or otherwise make resale difficult. If your college requires that someone with a student ticket to a sporting event show a student identification card containing a photo, it will be difficult to resell your low-price tickets to nonstudents who pay higher prices. When students at some universities buy computers at lower-than-usual prices, they must sign a contract that forbids resale of the computer. Disney prevents resale by locals who can buy a ticket at a lower price by checking driver’s licenses and requiring that the ticket be used for same-day entrance. Governments frequently aid price discrimination by preventing resale. Government tariffs (taxes on imports) limit resale by making it expensive to buy a branded good in a low-price country and resell it in a high-price country. For example, under U.S. trade laws, certain brand-name perfumes may not be sold in 10.1 Conditions for Price Discrimination 317 the United States except by their manufacturers. Similarly, if the countries have very different safety rules, a product sold in one country might not be legally sold in another. However, such a resale is legal for many products. Imported goods that go through legal, but unofficial channels that are unauthorized by the original manufacturer are said to sell in a gray market or parallel market. To make such a transaction unattractive Nikon provides a warranty that is only good in the country in which the good is supposed to be sold. Similarly, Canon sells a Rebel DSLR camera in the United States, but calls it the EOS DSLR elsewhere. M ini-Case Preventing Resale of Designer Bags During the holiday season, stores often limit how many of the hottest items— such as this year’s best-selling toy—a customer can buy. But it may surprise you that websites of luxury-goods retailers such as Saks Fifth Avenue, Neiman Marcus, and Bergdorf Goodman limit how many designer handbags a person can buy: “Due to popular demand, a customer may order no more than three units of this item every 30 days.” Why wouldn’t manufacturers and stores want to sell as many units as possible? How many customers can even afford more than three Prada Visone Hobo handbags at $4,950 each? The simple explanation is that the restriction has nothing to do with “popular demand.” Instead, it’s designed to prevent resale so as to enable manufacturers to price discriminate internationally. The handbag manufacturers pressure the U.S. retailers to limit sales to prevent anyone from buying large numbers of bags and reselling them in Europe or Asia where the same items in Prada and Gucci stores often cost 20% to 40% more. For example, the Prada Nappa Antique Tote sells for $1,280 at Saks Fifth Avenue in New York City, but sells for $1,570 on Prada’s Swiss website. A weak U.S. dollar makes such international resale even more attractive, which explains why Prada’s online site allows shipments only to selected countries, expressly forbids resale, and limits purchases. Not All Price Differences Are Price Discrimination Not every seller who charges consumers different prices is price discriminating. A firm price discriminates by charging different prices for units of a good that cost the same to produce. In contrast, newsstand prices and subscription prices for magazines differ in large part because of the higher cost of selling at a newsstand rather than the lower cost of mailing magazines directly to consumers. The 2013 price for 51 weekly issues of the Economist magazine for a year is $356 if you buy it at the newsstand, $160 for a standard print subscription, and $96 for a college student subscription. The difference between the newsstand cost and the standard subscription cost reflects, at least in part, the higher cost of selling magazines at a newsstand versus mailing them directly to customers, so this price difference does not reflect pure price discrimination. In contrast, the price difference between the standard subscription rate and the college student rate does reflect pure price discrimination because the two subscriptions are identical in every respect except the price. 318 CHAPTER 10 Pricing with Market Power Types of Price Discrimination Traditionally, economists focus on three types of price discrimination: perfect price discrimination, group price discrimination, and nonlinear price discrimination. With perfect price discrimination—also called first-degree price discrimination—the firm sells each unit at the maximum amount any customer is willing to pay. Under perfect price discrimination, price differs across consumers, and a given consumer may pay higher prices for some units than for others. With group price discrimination—also called third-degree price discrimination— the firm charges each group of customers a different price, but it does not charge different prices within the group. The price that a firm charges a consumer depends on that consumer’s membership in a particular group. Thus not all customers pay different prices—the firm sets different prices only for a few groups of customers. Group price discrimination is the most common type of price discrimination. A firm engages in nonlinear price discrimination (also called second-degree price discrimination) when it charges a different price for large purchases than for small quantities, so that the price paid varies according to the quantity purchased. With pure nonlinear price discrimination, all customers who buy a given quantity pay the same price; however, firms can combine nonlinear price discrimination with group price discrimination, setting different nonlinear price schedules for different groups of consumers. 10.2 Perfect Price Discrimination A firm with market power that knows exactly how much each customer is willing to pay for each unit of its good and that can prevent resale, can charge each person his or her reservation price: the maximum amount a person is willing to pay for a unit of output. Such an all-knowing firm can perfectly price discriminate. By selling each unit of its output to the customer who values it the most at the maximum price that person is willing to pay, the perfectly price-discriminating monopoly captures all possible consumer surplus. Perfect price discrimination is rare because firms do not have perfect information about their customers. Nevertheless, it is useful to examine perfect price discrimination because it is the most efficient form of price discrimination and provides a benchmark against which we can compare other types of nonuniform pricing. We now show how a firm with full information about consumer reservation prices can use that information to perfectly price discriminate. Next, we compare the market outcomes (price, quantity, surplus) of a perfectly price-discriminating monopoly to those of perfectly competitive and uniform-price monopoly firms. How a Firm Perfectly Price Discriminates A firm with market power that can prevent resale and has full information about its customers’ willingness-to-pay price discriminates by selling each unit at its reservation price—the maximum amount any consumer would pay for it. The maximum price for any unit of output is given by the height of the demand curve at that output level. In the demand curve facing a monopoly in Figure 10.1, the first customer is willing to pay $6 for a unit, the next is willing to pay $5, and so forth. A perfectly price-discriminating firm sells its first unit of output for $6. Having sold the first unit, the firm can get at most $5 for its second unit. The firm must drop its price by $1 for each successive unit it sells. 10.2 Perfect Price Discrimination 319 The monopoly can charge $6 for the first unit, $5 for the second, and $4 for the third, as the demand curve shows. Its marginal revenue is MR1 = $6 for the first unit, MR2 = $5 for the second unit, and MR3 = $4 for the third unit. Thus, the demand curve is also the marginal revenue curve. Because the firm’s marginal and average cost is $3 per unit, it is unwilling to sell at a price below $3, so it sells 4 units, point e, and breaks even on the last unit. p, $ per unit F IG U RE 10. 1 Perfect Price Discrimination 6 5 Demand, Marginal revenue 4 e 3 MC MR1 = $6 MR2 = $5 MR3 = $4 MR4 = $3 2 1 0 1 2 3 4 5 6 Q, Units per day A perfectly price-discriminating firm’s marginal revenue is the same as its price. As the figure shows, the firm’s marginal revenue is MR1 = $6 on the first unit, MR2 = $5 on the second unit, and MR3 = $4 on the third unit. As a result, if it can perfectly price discriminate, a firm’s marginal revenue curve is the same as its demand curve. This firm has a constant marginal cost of $3 per unit. It pays for the firm to produce the first unit because the firm sells that unit for $6, so its marginal revenue exceeds its marginal cost by $3. Similarly, the firm sells the second unit for $5 and the third unit for $4. The firm breaks even when it sells the fourth unit for $3. The firm is unwilling to sell more than four units because its marginal cost would exceed its marginal revenue on all successive units. Thus, like any profit-maximizing firm, a perfectly price-discriminating firm produces at point e, where its marginal revenue curve intersects its marginal cost curve. This perfectly price-discriminating firm earns revenues of MR1 + MR2 + MR3 + MR4 = $6 + $5 + $4 + $3 = $18, which is the area under its marginal revenue curve up to the number of units, four, it sells. If the firm has no fixed cost, its cost of producing four units is $12 = $3 * 4, so its profit is $6. Perfect Price Discrimination Is Efficient but Harms Some Consumers Perfect price discrimination is efficient: It maximizes the sum of consumer surplus and producer surplus. Therefore, both perfect competition and perfect price discrimination maximize total surplus. However, with perfect price discrimination, the entire surplus goes to the firm, whereas under competition consumers obtain some surplus. If the market illustrated in Figure 10.2 is competitive, the intersection of the demand curve and the marginal cost curve, MC, determines the competitive equilibrium at ec, 320 CHAPTER 10 Pricing with Market Power where price is pc and quantity is Qc. Consumer surplus is A + B + C, producer surplus is D + E, and society suffers no deadweight loss. The market is efficient because the price, pc, equals the marginal cost, MCc. With a single-price monopoly (which charges all its customers the same price), the intersection of the MC curve and the single-price monopoly’s marginal revenue curve, MRs, determines the output, Qs.5 The monopoly operates at es, where it charges ps. The deadweight loss from monopoly is C + E. This efficiency loss is due to charging a price, ps, above marginal cost, MCs, so less is sold than in a competitive market. F IG U RE 10. 2 Competitive, Single-Price, and Perfect Price Discrimination Outcomes perfect price discrimination equilibrium, the monopoly sells each unit at the customer’s reservation price on the demand curve. It sells Qd (= Qc ) units, where the last unit is sold at its marginal cost. Customers have no consumer surplus, but society has no deadweight loss. p, $ per unit In the competitive market equilibrium, ec, price is pc, quantity is Qc, consumer surplus is A + B + C, producer surplus is D + E, and society has no deadweight loss. In the single-price monopoly equilibrium, es, price is ps, quantity is Qs, consumer surplus falls to A, producer surplus is B + D, and deadweight loss is C + E. In the MC A es ps B C ec pc = MCc E D MCs Demand, MRd MRs Qs Qc = Qd Q, Units per day Monopoly Consumer Surplus, CS Producer Surplus, PS Total Surplus, TS = CS + PS Deadweight Loss Perfect Price Discrimination Competition Single Price A+B+C A 0 D+E B+D A+B+C+D+E A+B+C+D+E A+B+D A+B+C+D+E 0 C+E 0 5We assume that if we convert a monopoly into a competitive industry, the industry’s marginal cost curve—the lowest cost at which an additional unit can be produced by any firm—is the same as the monopoly MC curve. The industry MC curve is the industry supply curve (Chapter 8). 10.2 Perfect Price Discrimination 321 A perfectly price-discriminating firm sells each unit at its reservation price, which is the height of the demand curve. As a result, the firm’s price-discrimination marginal revenue curve, MRd, is the same as its demand curve. It sells the Qd unit for pc, where its marginal revenue curve, MRd, intersects the marginal cost curve, MC, so it just covers its marginal cost on the last unit. The firm is unwilling to sell additional units because its marginal revenue would be less than the marginal cost of producing them. A perfectly price-discriminating firm’s producer surplus from the Qd units it sells is the area below its demand curve and above its marginal cost curve, A + B + C + D + E. Its profit is the producer surplus minus its fixed cost, if any. Consumers receive no consumer surplus because each consumer pays his or her reservation price. The perfectly price-discriminating firm’s profit-maximizing solution has no deadweight loss because the last unit is sold at a price, pc, that equals the marginal cost, MCc, as in a competitive market. Thus, both a perfect price discrimination outcome and a competitive equilibrium are efficient. The perfect price discrimination solution differs from the competitive equilibrium in two important ways. First, in the competitive equilibrium, everyone is charged a price equal to the equilibrium marginal cost, pc = MCc; however, in the perfect price discrimination equilibrium, only the last unit is sold at that price. The other units are sold at customers’ reservation prices, which are greater than pc. Second, consumers receive some net benefit (consumer surplus, A + B + C) in a competitive market, whereas a perfectly price-discriminating monopoly captures all the surplus or potential g