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For much of the twentieth century, macroeconomics was divided between those who believed government could actively stabilize the economy and those who insisted that markets, left to themselves, would do a better job. The Chicago School and its macroeconomic offshoots—Monetarism and New Classical Macroeconomics—became the most influential voice for the latter position. Each framework built on the one before, but each also introduced sharp breaks that redefined what economists thought about money, expectations, and the limits of policy.
The Chicago School is not a single doctrine but a methodological tradition that took shape at the University of Chicago from the 1920s onward. Its early architects—Frank Knight, Jacob Viner, and Henry Simons—shared a commitment to neoclassical price theory as a tool for analyzing nearly any social question. Markets, they argued, were remarkably efficient at coordinating decentralized information, and government intervention usually made things worse. This was not a blanket laissez-faire dogma; it was a working hypothesis that had to be tested against evidence.
What made the Chicago School distinctive was its insistence on treating all economic behavior—including decisions about crime, education, and family—as the outcome of rational individuals responding to incentives. Milton Friedman and George Stigler, who came to prominence in the postwar decades, turned this approach into a rigorous empirical program. Friedman’s 1957 book A Theory of the Consumption Function, for example, used permanent-income logic to argue that consumers smooth their spending over time, a claim that had direct implications for how fiscal policy worked. The school’s microeconomic commitments—rationality, equilibrium, the power of relative prices—became the foundation for its later macroeconomic interventions.
By the 1950s, the dominant macroeconomic framework was the Neoclassical Synthesis, which combined Keynesian demand management with neoclassical microeconomics. Monetarism emerged from within the Chicago tradition as a direct challenge to that synthesis. Friedman, its leading figure, revived the quantity theory of money, arguing that changes in the money supply were the primary driver of nominal income and, in the long run, of inflation alone. In his 1967 presidential address to the American Economic Association, Friedman introduced the natural rate of unemployment: the idea that there was no permanent trade-off between inflation and unemployment. Any attempt to push unemployment below its natural rate would only accelerate inflation, not raise output.
Monetarism differed from the Neoclassical Synthesis in two crucial ways. First, it denied that fiscal policy was an effective stabilization tool; only monetary policy mattered, and even then only when it was predictable. Second, it argued that discretionary policy was inherently destabilizing because of long and variable lags. Friedman’s proposed solution was a fixed monetary growth rule—a sharp contrast to the activist fine-tuning that Keynesians recommended.
The framework gained enormous credibility when the stagflation of the 1970s—high inflation combined with high unemployment—seemed to confirm the natural-rate hypothesis. Central banks in the United States and Britain adopted monetarist targets in the early 1980s. Yet strict monetarism faded quickly after that. Financial innovation made the money supply harder to define and control, and central banks found that targeting interest rates worked better in practice. What survived was the core insight: controlling inflation is a central bank’s primary responsibility, and expectations matter for how policy affects the economy.
Even as Monetarism was being implemented, a younger generation of Chicago-trained economists pushed its logic further. Robert Lucas, Thomas Sargent, and Edward Prescott developed New Classical Macroeconomics, which broke from Monetarism by introducing rational expectations. Friedman had assumed that people formed expectations adaptively—they looked at past inflation and adjusted slowly. Lucas argued that people are forward-looking: they use all available information, including knowledge of the policy regime itself, to form expectations about the future.
This seemingly technical change had radical implications. If people anticipate policy, then only unanticipated changes in the money supply can affect real output. Anticipated policy is neutral—it changes prices but not employment or production. This was the policy-ineffectiveness proposition, and it went far beyond Friedman’s more cautious claim that policy had limited effects. Lucas also formulated the Lucas critique: any econometric model estimated from past data would break down when the policy regime changed, because people’s expectations would shift. This critique undermined the large-scale Keynesian models that had guided policy for decades.
New Classical Macroeconomics also introduced real business cycle (RBC) theory, developed by Finn Kydland, Prescott, and others. RBC theory argued that business cycles were not caused by monetary shocks at all but by real shocks—especially changes in technology. Fluctuations in output and employment, on this view, were efficient responses to changing productivity, not market failures requiring government intervention. This was a dramatic departure from both Keynesian and monetarist thinking, which had always treated recessions as problems to be solved.
The three frameworks share a deep family resemblance. All begin from neoclassical microfoundations: individuals are rational, markets clear, and prices convey information efficiently. All are skeptical of discretionary government intervention, preferring rules or credible commitments. All treat inflation as ultimately a monetary phenomenon.
Yet the disagreements are just as important. Monetarism coexists with the Chicago School as one application of its methods, but the school itself is broader—it includes microeconomists who never worked on money at all. New Classical Macroeconomics, in turn, both extends and challenges Monetarism. It extends monetarist logic by making expectations rational rather than adaptive, which strengthens the case for policy rules. But it also challenges Monetarism by suggesting that even anticipated monetary policy has no real effects—a claim Friedman never accepted. Friedman continued to believe that money mattered in the short run; Lucas and Sargent argued that only surprises mattered.
New Classical Macroeconomics also narrowed the scope of macroeconomics. Where Monetarism had focused on the money supply and aggregate demand, RBC theory shifted attention to supply-side shocks and the efficiency of fluctuations. This narrowing provoked a strong reaction from New Keynesian economists, who argued that sticky prices and wages could generate non-neutralities even with rational expectations. The resulting synthesis—the New Neoclassical Synthesis or DSGE framework—absorbed rational expectations and microfoundations from New Classical Macroeconomics while reintroducing the nominal rigidities that Monetarism and New Classical theory had downplayed.
Contemporary macroeconomics is shaped by the legacy of all three frameworks. Most macroeconomists agree that expectations are central to policy effectiveness, that central banks should focus on inflation control, and that models must have explicit microfoundations. These are direct inheritances from the Chicago tradition. The sharp disagreements that remain are about how much rigidity exists in real economies. New Classical-leaning economists still emphasize that fluctuations may be efficient; New Keynesian-leaning economists argue that sticky prices and wages create genuine welfare losses that policy can address. The debate is no longer about whether government should intervene but about how much, and under what conditions, intervention can improve outcomes.
The Chicago School, Monetarism, and New Classical Macroeconomics together transformed macroeconomics from a field focused on aggregate relationships into one built on individual choice and expectations. Their influence persists not as a settled orthodoxy but as a set of tools and questions that every macroeconomist must confront.