Keynesian Economics
An economic theory arguing that aggregate demand — driven by government spending and fiscal policy — is the primary determinant of short-run economic output and employment.
What is Keynesian Economics?
Keynesian economics, developed by British economist John Maynard Keynes in 'The General Theory of Employment, Interest and Money' (1936), argues that total spending (aggregate demand) drives short-run economic output, and that markets do not automatically self-correct to full employment. When private sector demand collapses in a recession, Keynes argued, government spending should fill the gap — deficit spending and fiscal stimulus can restore output through the multiplier effect (each dollar of government spending generates more than one dollar of economic activity). Keynesians also accept that prices and wages are 'sticky' downward, meaning unemployment can persist without government intervention. Keynesian ideas shaped the New Deal, post-WWII macroeconomic policy, and stimulus programs like the 2009 American Recovery and Reinvestment Act and 2020–2021 COVID relief packages. Critics (monetarists and supply-siders) argue Keynesian stimulus creates inflation, crowds out private investment, and produces long-run debt burdens.
Example
During the 2008–2009 Global Financial Crisis, governments worldwide applied Keynesian stimulus: the U.S. passed the $831 billion American Recovery and Reinvestment Act; China launched a $586 billion infrastructure package; and central banks slashed interest rates to near zero. GDP contraction was severe but shorter than the Great Depression, which Keynesians argue demonstrates the effectiveness of fiscal intervention in stabilizing aggregate demand during a demand-driven collapse.