Few relationships in economics have promised so much and delivered so little as the Phillips Curve — the elegant inverse correlation between unemployment and inflation that once seemed to offer central bankers a reliable steering wheel for the economy. The idea is seductively simple: when unemployment falls, workers gain bargaining power, wages rise, and inflation follows. When unemployment rises, the opposite occurs. Plot the two variables on a graph and you get a smooth, downward-sloping curve that suggests policymakers can simply choose their preferred combination of the two evils.
The problem is that the curve keeps moving, disappearing, or flattening into irrelevance precisely when it matters most.
The rise of a beautiful theory
New Zealand economist A.W. Phillips published his original 1958 paper examining nearly a century of British wage data, and the relationship he found seemed robust enough to build policy around. American economists Paul Samuelson and Robert Solow quickly adapted the framework for U.S. conditions, and by the 1960s the Phillips Curve had become the intellectual foundation of macroeconomic management. The Kennedy and Johnson administrations embraced it enthusiastically, believing they could fine-tune the economy by accepting slightly higher inflation in exchange for lower unemployment.
Then came the 1970s, when the United States experienced both high inflation and high unemployment simultaneously — a phenomenon the curve said was impossible. Stagflation didn't just embarrass the theory; it helped end careers and reshape political coalitions. Milton Friedman and Edmund Phelps had already warned that any stable tradeoff would prove illusory once workers adjusted their inflation expectations, but the intellectual establishment had largely ignored them until reality intervened.
The curve that keeps flattening
The relationship has continued to confound. During the long expansion following the 2008 financial crisis, unemployment fell to levels that traditional models predicted would generate significant inflation. It didn't. Economists scrambled to explain the "missing inflation" with theories about globalization suppressing wages, technology reducing worker bargaining power, and inflation expectations becoming so firmly anchored that the old dynamics no longer applied.
Then came the post-pandemic period, when inflation surged even as unemployment remained elevated by historical standards — the curve apparently inverting rather than simply flattening. Supply shocks, fiscal stimulus, and pandemic-distorted labor markets all received blame, but the deeper lesson was familiar: the relationship between unemployment and inflation is contingent, unstable, and far more complex than any two-dimensional graph can capture.
Why it still haunts policy
Central bankers officially acknowledge the curve's limitations, yet its ghost continues to shape their thinking. When unemployment falls, they instinctively worry about inflation. When they want to cool prices, they accept that higher unemployment may be necessary. The framework persists partly because no superior alternative has emerged, and partly because abandoning it entirely would mean admitting that monetary policy operates with even less precision than the public already suspects.
Our take
The Phillips Curve's persistence despite its failures reveals something important about how economic knowledge actually works. Policymakers need frameworks, even imperfect ones, to organize their thinking and justify their decisions. The curve provides a story — about tradeoffs, about the costs of fighting inflation, about the limits of what policy can achieve — that remains politically and intellectually useful regardless of its empirical track record. Economics, it turns out, is as much about narrative as numbers.
