An economic theory of total spending in the economy and its effects on output and inflation. Keynesian economics was developed by the British economist John Maynard Keynes during the 1930s in an attempt to understand the Great Depression. Keynes advocated increased government expenditures and lower taxes to stimulate demand and pull the global economy out of the Depression. Subsequently, the term “Keynesian economics” was used to refer to the concept that optimal economic performance could be achieved – and economic slumps prevented – by influencing aggregate demand through activist stabilization and economic intervention policies by the government. Keynesian economics is considered to be a “demand-side” theory that focuses on changes in the economy over the short run.