NAIRU stands for the Non-Accelerating Inflation Rate of Unemployment, a concept central to modern macroeconomic policy. It refers to the level of unemployment at which inflation neither rises nor falls. If actual unemployment falls below the NAIRU, the theory predicts that tight labor markets will push wages and prices upward; if unemployment is above it, inflationary pressures should ease.
The concept evolved from Milton Friedman's and Edmund Phelps's late-1960s critiques of the Phillips curve, which had posited a stable trade-off between unemployment and inflation. Friedman's 1968 American Economic Association presidential address introduced the related "natural rate of unemployment," arguing that any attempt to permanently push unemployment below this rate would only generate accelerating inflation. The term NAIRU itself was popularized in the 1970s and 1980s, notably through work by James Tobin, Franco Modigliani, and Robert Gordon.
NAIRU is not directly observable. Central banks and institutions such as the U.S. Congressional Budget Office (CBO), the OECD, and the IMF estimate it using statistical models, but estimates vary widely and are frequently revised. In the United States, NAIRU estimates have generally fallen from around 6% in the 1980s to roughly 4–5% in recent decades, though the figure remains contested.
Policy implications are significant. The U.S. Federal Reserve and the European Central Bank implicitly reference NAIRU-style reasoning when calibrating interest rates under their dual or price-stability mandates. However, the concept has drawn criticism:
- Measurement uncertainty: confidence intervals around estimates are large.
- Instability: NAIRU shifts with demographics, productivity, and labor-market institutions.
- Empirical challenges: the late-1990s U.S. expansion and the post-2015 period saw low unemployment without significant inflation, while 2021–2023 inflation surged even at moderate unemployment levels.
Heterodox economists, including post-Keynesians, reject NAIRU as either tautological or a justification for tolerating involuntary unemployment.
Example
In its 2024 Budget and Economic Outlook, the U.S. Congressional Budget Office estimated the noncyclical rate of unemployment—its NAIRU equivalent—at roughly 4.4%, informing projections of labor-market slack.
Frequently asked questions
They are closely related and often used interchangeably. The natural rate, from Friedman and Phelps, emphasizes long-run labor-market equilibrium, while NAIRU is defined specifically by the inflation-stabilizing property. In practice most empirical estimates treat them as equivalent.
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