Keynesian economics ( KAYN-zee-ən; sometimes called Keynesianism) are the various macroeconomic theories about how in the short run – and especially during recessions – economic output is strongly influenced by aggregate demand (total demand in the economy). In the Keynesian view, aggregate demand does not necessarily equal the productive capacity of the economy; instead, it is influenced by a host of factors and sometimes behaves erratically, affecting production, employment, and inflation.Keynesian economics developed during and after the Great Depression, from the ideas presented by John Maynard...