Time Study: Definition, Procedure and Methods
Meaning and Definition of Time Study:
When a customer wants to purchase some products, then he usually compares the
prices with those of similar products, which are being manufactured by other
producers. Therefore, to give competitive quotations, estimation of accurate labour cost
is very essential as it has got large effect on the price.
If the prices are higher, then, the manufacturer may not get supply orders and if these
are lower, then losses may occur. Thus exact estimation of time is very essential for
correctly pricing. As labour cost depends upon time estimation, therefore, time must be
estimated correctly as far as possible.
Secondly, whenever a customer contracts for the purchase of certain products then he
desires that the products should reach to him at a promised date which is only possible
when manufacturer is aware of the time to be taken by the product during
manufacture. Therefore, to find the correct manufacturing time for product, time study
is performed by the Time Study Engineer.
Definitions:
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Time study may be defined as “the art of observing and recording the time required
to do each detailed element of an industrial operation”.
The term industrial operation includes manual, mental and machining
operations, where:
(i) Manual time is divided into three types of operations, i.e. handling of tools, machines
and materials.
(ii) Mental time includes time taken by the worker for thinking over some operations.
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(iii) Machining time includes time taken by the machines in doing its share of work.
Thus time study standardizes the time taken by average worker to perform these
operations.
It can also be defined in the following words “work measurement” is the application of
techniques designed to establish the time for a qualified worker to carry out a specified
job at a definite level of performance.
Use of Time Study:
(i) It is useful in determining the standard time for various operations, which helps in
fixing wages and incentives.
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(ii) It is useful to estimate the cost of a product accurately.
(iii) It helps in production control.
(iv) It helps in predicting accurately as to when the work will be completed and hence
customers can be promised to take delivery on a fixed date.
(v) Using the time study techniques, it can be found that how much machines an operator can run.
Procedure for Time Study:
For conducting time study, average workers and average machines are selected. This
study is conducted by the Time Study expert, who should be familiar with all
information’s related to the job and the conditions in which it is being done. The
location of the expert should be such that he can watch all the operations and the
movement of the workers without disturbing them from suitable distance.
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He performs time study in the following stages:
(a) Analysis of Work:
The complete job and its operations are split up into various elements. These elements
are finalised after conducting motion study. In the end, time required for the job
preparation, cleaning of machine and oiling etc. should be included. Thus time study
includes all the tasks performed by the worker and not only the effective work.
(b) Standardisation of Methods:
Before conducting time-study, all the constituents of the job such as materials,
equipment, tools, working conditions and methods are standardised. The method
should be easy, safe and quickest in the given conditions, so that it can be accepted by
workers.
(c) Making Time Study:
The study is done on a printed time study record sheet as shown below which is fixed
on a board known as Time Study Board. On one corner generally right hand top corner
a stop watch is placed. This stop watch should have a decimal scale dial so that it can
read up to 0.001 minute.
Different time readings of one element are recorded in the corresponding column of the
record sheet. Several sets of readings are taken to arrive at an accurate result. After
noting all these readings, average time is calculated, neglecting abnormal values, if any.
This average time is multiplied by a levelling factor also called ‘Rating Factor’, which is
generally assumed as 90-120% to get the time required by a normal worker. The
multiple of average time and rating factor is known as “Normal Time”.
Some allowances such as personal allowance (20%), fatigue allowance (5%),
preparation allowance (5%) are added in normal time to obtain the standard time. The
standard time is the basis for the calculation of wages and incentives.
Thus, Standard time = Average Time × Rating factor + Other allowances.
Standard Time:
It is the time, which is taken by a normal worker for a specific task or job, working
under moderate conditions and includes other allowances such as fatigue, setting of
tool and job, repairing of tool, checking of job etc.
Rating Factor:
Time study engineer multiplies actual time with a factor known as “Rating Factor” or
“Levelling Factor” to get the average time which a normal worker would take. This is
expressed as a percentage of the efficiency of representative operator, which indicates
how efficient an operator is in comparison to some of his average fellow workers.
Performance Rating:
Performance rating is that process, during which the time study engineer compares the
performance of the operator under observation with his own concept of normal
performance.
In mathematical term,
The concept of normal performance, must be such that the time standards are set from
it, are within the capacity of the majority of workers in the enterprise.
It would be of no use in setting standards so high that only the best worker could attain
them since programmes or estimates based on them would never be fulfilled.
Similarly low standard would result very high earnings for some of the workers
and consequently, excessively high labour cost of the product and very large
difference in the earnings of the workers:
Methods of Rating:
Following are the important methods used for performance rating:
1. Speed Rating.
2. Westinghouse System of Rating.
3. Synthetic Rating.
4. Objective Rating.
5. Physiological Evaluation of Performance Rating.
1. Speed Rating:
This rating procedure consists of judging the pace or speeds of the operator’s
movements in relation to a normal pace and is noted as a factor. This rating is applied
to each element and observed time for each element is multiplied by this factor (the
ratio of observed speed to expected speed) to get the normal time for the element.
2. Westinghouse System of Rating:
A four-factor system of Performance Rating was developed at Westinghouse.
These factors are:
1. Skill
2. Effort
3. Conditions
4. Consistency
3. Synthetic Rating:
In this method, performance of the worker is rated from the values already known as
P.M.T.S. (Predetermined Motion Time System). In this procedure, time study is done in
the usual manner and then actual time obtained for certain elements from this study
are compared with that of known standards.
The ratio of standard time of a particular element to that of observed time to the same
element is rating factor for the study. The rating factor for the study is the average of
rating factors obtained for different elements of the study.
Efforts must be made to determine the rating factors for as many elements as possible.
In this method, it is assumed that performance for the whole of the study will be same
as that obtained in these elements.
If, R = Performance Rating factor.
P = Predetermined standard for an element.
A = Average of actual time obtained in the time study for that element.
Then R = P/A
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