Inflation, Unemployment, and Expectations

Chapter 18 companion lesson

An unexpected increase in aggregate demand can lower unemployment for a time. Once workers and firms revise their inflation expectations, that favorable-looking tradeoff changes. Expectations are the hinge.

How does the CLEP test the short-run phillips curve and ad – as?

The short-run Phillips curve shows an inverse relation between inflation and unemployment for a given expected inflation rate and supply environment. Its downward slope corresponds to movements along SRAS caused by aggregate-demand changes. Stronger AD raises output and the price level; firms hire more, so unemployment falls while inflation rises.

A fall in AD reverses the movement. Output falls, unemployment rises, and inflation declines relative to its previous path. This is often disinflation rather than deflation: the price level can continue rising at a slower rate. Read whether the vertical axis is inflation rate or price level.

The Phillips curve does not replace AD – AS. It reorganizes the same short-run demand outcomes using unemployment and inflation. A point with output above potential in AD – AS corresponds to unemployment below its natural rate and inflation above expected on the SRPC. A recessionary gap corresponds to unemployment above natural and weaker inflation.

How does the CLEP test expected inflation and the long-run phillips curve?

Expected inflation affects wage contracts, price setting, nominal interest rates, and supply decisions. A simple expectations-augmented relation says inflation equals expected inflation minus a term related to unemployment above its natural rate, plus supply shocks. When unemployment equals natural and shocks are absent, actual inflation equals expected inflation.

Suppose expansion lowers unemployment below natural and raises inflation unexpectedly. Workers eventually demand faster nominal wage growth to protect purchasing power; firms raise prices to cover higher costs. SRAS shifts left and the SRPC shifts upward. Unemployment returns to natural at the higher inflation rate.

The long-run Phillips curve is vertical at the natural rate of unemployment. Once expectations adjust, different steady inflation rates can coexist with the same natural unemployment rate. There is no permanent inflation-unemployment tradeoff from demand management.

What should you know about adaptive and rational expectations, credibility, and indexation?

Adaptive expectations are formed by updating from recent inflation. If inflation has been 4 percent, people may expect something near 4 next period and revise after errors. Adjustment can be gradual, allowing demand policy temporary real effects while expectations catch up.

Rational expectations use available information, including the policy regime, without implying perfect foresight. Forecast errors occur, but they are not systematically predictable from known information. A publicly announced, credible policy can therefore affect wages and prices before implementation.

If a central bank announces expansion that everyone anticipates, workers and firms may immediately raise expected inflation. SRPC and SRAS shift before output receives a surprise boost, reducing the real effect. An unanticipated policy can move output temporarily, but repeated systematic surprises are difficult when the rule is understood.

How does the CLEP test disinflation, sacrifice ratios, supply shocks, and hysteresis?

Disinflation is a reduction in the inflation rate, not a fall in the price level. If inflation falls from 8 to 3 percent, prices still rise, but more slowly. Deflation is negative inflation and a falling price level.

To reduce entrenched inflation, contractionary policy lowers AD. Output falls below potential and unemployment rises above natural in the short run. Lower demand and labor-market slack reduce wage and price growth; expected inflation eventually falls, shifting SRPC downward and SRAS right. Output can return to potential at a lower inflation rate.

The sacrifice ratio measures cumulative percentage output loss associated with reducing inflation by one percentage point under a stated convention. A ratio of 2 means a disinflation of 3 points is associated with cumulative output loss of about 6 percent of annual GDP. It is an empirical summary, not a universal constant.

What is the CLEP likely to ask?

Expect SRPC movements from AD changes, SRPC shifts from expected inflation or supply shocks, a vertical LRPC, natural-rate reasoning, and the output cost of disinflation.

A useful check is to name the model before doing arithmetic. Then write the first change, the intermediate market response, and the final macroeconomic result. This keeps a plausible distractor from borrowing one true step and attaching it to the wrong conclusion.

Can you do these without notes?

1. Translate four AD – AS changes into inflation-unemployment movements and distinguish movement along SRPC from a shift.
2. Explain why LRPC is vertical, trace expectation adjustment after surprise expansion, and distinguish a curve shift from a change in the natural rate.
3. Compare adaptive and rational expectations, explain credibility and forward guidance, and identify both protection and persistence effects of indexation.

For each prompt, say why the tempting wrong answer fails. That extra sentence is often the difference between recognizing a term and being able to use it under time pressure.