<P> The usage of long run and short run in macroeconomics differs somewhat from the above microeconomic usage . John Maynard Keynes in 1936 emphasized fundamental factors of a market economy that might result in prolonged periods away from full - employment . In later macroeconomic usage, the long run is the period in which the price level for the overall economy is completely flexible as to shifts in aggregate demand and aggregate supply . In addition there is full mobility of labor and capital between sectors of the economy and full capital mobility between nations . In the short run none of these conditions need fully hold . The price level is sticky or fixed in response to changes in aggregate demand or supply, capital is not fully mobile between sectors, and capital is not fully mobile across countries due to interest rate differences among countries and fixed exchange rates . </P> <P> A famous critique of neglecting short - run analysis was by Keynes, who wrote that "In the long run, we are all dead", referring to the long - run proposition of the quantity theory of money, for example, a doubling of the money supply doubling the price level . </P>

In microeconomics the short run is defined as which of the following