new classical and new Keynesian economics
By the 1970s, economics had a problem: stagflation — high inflation and high unemployment at once — had broken the simple old Keynesian models, and a new question dominated the field. If people are smart and look ahead, can government and central-bank policy really steer the economy, or will people see it coming and undo it? Two camps formed to answer, both demanding that big-picture macro models be built up from how individual people actually decide. They are the new classical and new Keynesian schools, and their debate shaped modern macroeconomics.
Both schools share a foundation: macroeconomics should rest on 'microfoundations' (the choices of rational households and firms) and on rational expectations (people use all available information and are not fooled the same way twice). From there they split. The new classical school, led by Robert Lucas, took rationality to its sharp conclusion: if people anticipate policy, predictable government stimulus is largely neutralized, prices and wages adjust fast, and markets clear quickly, so activist demand management is mostly useless or harmful. The new Keynesian school accepted rational expectations but added realistic frictions — prices and wages are 'sticky' (a restaurant reprints menus only occasionally, contracts fix wages for a year) and information is imperfect. Because of these frictions, demand shortfalls can still cause recessions, and monetary and fiscal policy can still help.
These schools matter because their synthesis is essentially what central banks and academic macroeconomics use today: the workhorse models running monetary policy combine rational, forward-looking agents with sticky prices, a blend often called the 'new neoclassical synthesis'. The new classical critique permanently raised the bar, insisting policy take people's expectations seriously. But there are honest caveats. The assumption of fully rational expectations is strong and often unrealistic (behavioral economics pushes back); these elaborate models famously failed to foresee the 2008 crisis and underweighted finance; and 'microfoundations' can give an illusion of rigor while resting on shaky assumptions. The lasting lesson is humbler than either camp first claimed: expectations and frictions both matter, and macroeconomics is harder than any single model admits.
If a central bank promises easy money to boost output, new classical theory says people foresee the resulting inflation and demand higher wages and prices at once, so output barely moves. New Keynesians reply that sticky menus and year-long wage contracts delay that adjustment, leaving room for policy to work.
Do people instantly undo policy, or do sticky prices give it room?
Fully rational expectations is a strong, often unrealistic assumption (behavioral economics pushes back), and these elaborate models famously failed to foresee the 2008 crisis and underweighted finance. 'Microfoundations' can give an illusion of rigor on shaky assumptions.