BharatNotes What is Phillips Curve?
The Phillips Curve is a graphical representation of the short-run inverse relationship between the unemployment rate and the rate of inflation. It is named after economist A.W. (Alban William) Phillips, who, in a 1958 article in the journal Economica, studied UK data from 1861 to 1957 and found that money wages rose rapidly when unemployment was low and slowly when unemployment was high. The intuition is straightforward: when jobs are plentiful and unemployment is low, employers compete for scarce workers by offering higher wages, which feeds into higher prices (inflation); when unemployment is high, wage and price pressures ease.
Short-Run Trade-off vs Long-Run Neutrality
The original curve implied a stable menu of choices for policymakers — accept higher inflation to lower unemployment, or accept higher unemployment to curb inflation. This view broke down during the stagflation of the 1970s, when many economies experienced high inflation and high unemployment together — something the simple curve said should not happen.
Milton Friedman (in his 1967 AEA presidential address, published 1968) and Edmund Phelps argued the trade-off exists only in the short run, because people are not permanently fooled by inflation. Once workers and firms come to expect higher inflation, they build it into wage demands and pricing, so the temporary employment gain disappears. This produced the expectations-augmented Phillips Curve and the idea of a Natural Rate of Unemployment, also called the NAIRU (Non-Accelerating Inflation Rate of Unemployment). In the long run the curve is held to be vertical at the natural rate — meaning no permanent inflation-unemployment trade-off.
Short-Run vs Long-Run: A Comparison
| Aspect | Short-Run Phillips Curve | Long-Run Phillips Curve |
|---|---|---|
| Shape | Downward-sloping | Vertical |
| Trade-off | Inflation vs unemployment exists | No trade-off |
| Role of expectations | Inflation expectations fixed | Expectations fully adjust |
| Unemployment outcome | Can fall below natural rate temporarily | Settles at natural rate (NAIRU) |
| Policy implication | Demand stimulus can cut unemployment briefly | Stimulus only raises inflation |
Current Relevance and Debate
Since the 1990s, many economists argue the curve has "flattened" — inflation has become less responsive to changes in unemployment, complicating central-bank policy (Cleveland Fed and St. Louis Fed research, 2019-2022). The flattening is debated: some attribute it to credible inflation-targeting by central banks anchoring expectations, others to structural and global factors. The 2021-22 global inflation surge — driven by pandemic-era fiscal and monetary stimulus colliding with supply-chain constraints — revived interest in whether the relationship still holds.
UPSC Angle
For Indian Economy (GS3), the Phillips Curve is the analytical backbone for discussing the RBI's flexible inflation-targeting framework, the inflation-growth trade-off, and why central banks cannot permanently lower unemployment through easy money. Aspirants should be able to distinguish the short-run curve (trade-off) from the long-run vertical curve (no trade-off), and explain NAIRU and the role of inflation expectations.
Don't confuse with: Okun's Law (which links unemployment to GDP/output, not inflation) and the Laffer Curve (tax rates versus revenue) — these are frequently mixed up.
