In economics, the multiplier effect or spending multiplier is the idea that an initial amount of spending (usually by the government) leads to increased consumption spending and so results in an increase in national income greater than the initial amount of spending. In other words, an initial change in aggregate demand causes a change in aggregate output for the economy that is a multiple of the initial change. However, multiplier values less than one have been empirically measured, suggesting that government spending crowds out private investments and spending that would have otherwise happened. The existence of a multiplier effect was initially proposed by Ralph George Hawtrey in 1931. It is particularly associated with Keynesian economics Some other schools of economic thought reject or downplay the importance of multiplier effects, particularly in terms of the long run. The multiplier effect has been used as an argument for the efficacy of government spending or taxation relief to stimulate aggregate demand.