---
title: "Neoclassical Phillips Curve | Principles of Economics"
description: "Neoclassical Phillips Curve shows a short-run inflation-unemployment tradeoff, but no long-run tradeoff, in Principles of Economics policy analysis."
canonical: "https://fiveable.me/principles-econ/key-terms/neoclassical-phillips-curve"
type: "key-term"
subject: "Principles of Economics"
unit: "Unit 26"
---

# Neoclassical Phillips Curve | Principles of Economics

## Definition

The Neoclassical Phillips Curve is a model in Principles of Economics showing a short-run tradeoff between inflation and unemployment, but no long-run tradeoff as the economy returns to full-employment equilibrium.

## What It Is

The Neoclassical Phillips Curve is the version of the Phillips Curve used in Principles of Economics to show that inflation and unemployment can move in opposite directions in the short run, but not forever. It combines the older Phillips Curve idea with the classical belief that markets tend to self-correct back to full employment.

In the short run, policymakers may be able to lower unemployment by using expansionary monetary or fiscal policy. That kind of policy increases spending in the economy, which can raise output and push firms to hire more workers. The catch is that higher demand can also push prices upward, so lower unemployment may come with higher inflation.

That short-run tradeoff is why the curve slopes downward in many textbook diagrams. But the neoclassical version does not treat that tradeoff as permanent. It says wages and prices eventually adjust, expectations catch up, and the economy moves back to its long-run equilibrium.

In the long run, the curve is vertical at the natural rate of unemployment, which means inflation changes do not create a lasting unemployment choice. If policymakers keep trying to stimulate the economy, workers and firms begin to expect more inflation, contracts adjust, and unemployment returns to its natural level anyway.

This is where the neoclassical part matters. The model reflects the idea that the economy has a built-in tendency to return to full employment, especially when prices and wages are flexible enough to adjust over time. So the curve is not saying policy does nothing. It is saying policy can affect unemployment for a while, but it cannot permanently trade higher inflation for lower unemployment.

A good way to think about it is this: short run, policy can move the economy around the curve. Long run, the economy settles back where the vertical line says it should be.

## Why It Matters

The Neoclassical Phillips Curve shows up whenever Principles of Economics asks how much power government policy really has over the macroeconomy. It connects the neoclassical view of self-correction to the practical policy debate over whether officials should try to fine-tune unemployment or focus on price stability.

This term also helps you read graphs correctly. If you see unemployment falling while inflation rises, the neoclassical Phillips Curve gives you the explanation for the short run. If the question asks what happens after wages, prices, and expectations adjust, the model says unemployment will drift back toward its natural rate instead of staying lower forever.

It matters for policy questions because it changes the goal of stabilization policy. A neoclassical answer often favors restraint, predictable policy, and letting markets adjust rather than trying to exploit a temporary tradeoff. That makes it a direct match for essays and discussion questions about inflation, unemployment, and government intervention.

It also connects to broader ideas like rational expectations and supply-side thinking. If people expect policy to raise inflation, they may negotiate higher wages or adjust prices faster, which weakens any short-run boost. So this term is not just about a curve on a graph, it is about how expectations and adjustment processes shape the whole economy.

## Connections

### Classical Theory of Employment

This is the backbone of the neoclassical view. It says the economy tends to self-correct toward full employment, so unemployment is not something policy can permanently fix just by boosting demand. The Neoclassical Phillips Curve uses that idea to explain why any inflation-unemployment tradeoff is temporary.

### A.W. Phillips Curve

The original Phillips Curve came from an observed inverse relationship between inflation and unemployment. The neoclassical version keeps that short-run relationship but adds the long-run vertical result. If you confuse the two, you may miss why the tradeoff disappears over time.

### Long-Run Equilibrium

This is where the economy ends up after wages, prices, and expectations adjust. In the Neoclassical Phillips Curve, long-run equilibrium is the point where inflation no longer buys lower unemployment. That is why the curve becomes vertical in the long run.

### [Rational Expectations](/principles-econ/key-terms/rational-expectations)

If people expect higher inflation, they change wages, prices, and contracts sooner. That reduces the ability of policy to keep unemployment below its natural rate. This idea helps explain why the short-run tradeoff can shrink when people anticipate policy moves.

## On the AP Exam

A quiz or short-answer question may give you a graph and ask whether a policy shift changes unemployment permanently or only temporarily. Use the Neoclassical Phillips Curve to say that expansionary policy can lower unemployment in the short run, but the long-run result is higher inflation and a return to the natural rate of unemployment. If you get a scenario about the government trying to push unemployment below equilibrium, explain the adjustment process, wages and prices rise, expectations catch up, and the curve ends up vertical in the long run.

For essay prompts, this term is useful when comparing Keynesian and neoclassical policy views. You can use it to argue that demand management has limits and that stable inflation matters more than trying to exploit a short-run tradeoff forever. If a question includes a shift in inflation expectations, point out that the short-run curve can move or the tradeoff can weaken as expectations change.

## Neoclassical Phillips Curve vs A.W. Phillips Curve

The A.W. Phillips Curve is the original relationship between inflation and unemployment based on historical data. The Neoclassical Phillips Curve is the later policy model that keeps the short-run tradeoff but says there is no long-run tradeoff because the economy returns to full employment.

## Key Takeaways

- The Neoclassical Phillips Curve says inflation and unemployment can trade off in the short run, but not in the long run.
- In Principles of Economics, it reflects the idea that the economy tends to self-correct back to full-employment equilibrium.
- Expansionary policy may lower unemployment temporarily, but it usually raises inflation if pushed too far.
- The long-run Phillips Curve is vertical, which means there is no permanent inflation-unemployment tradeoff.
- This model is a common way to explain why neoclassical economists prefer price stability over repeated demand stimulus.

## FAQs

### What is the Neoclassical Phillips Curve in Principles of Economics?

It is a model that says there can be a short-run tradeoff between inflation and unemployment, but no long-run tradeoff. In the long run, the economy returns to its natural or full-employment level of output. That is why the long-run curve is vertical.

### How is the Neoclassical Phillips Curve different from the original Phillips Curve?

The original Phillips Curve describes an inverse relationship between inflation and unemployment. The neoclassical version adds the idea that this relationship only lasts in the short run. After wages, prices, and expectations adjust, unemployment returns to its natural rate.

### Why is the long-run Neoclassical Phillips Curve vertical?

It is vertical because inflation does not permanently determine unemployment. If policymakers try to hold unemployment below its natural rate, higher inflation eventually gets built into wages, prices, and expectations. Once that happens, unemployment moves back to equilibrium.

### How do you use the Neoclassical Phillips Curve in a policy question?

Use it to explain why stimulus can reduce unemployment for a while but cannot keep it low forever without rising inflation. It is especially useful when a prompt asks whether government can permanently choose more jobs by tolerating higher inflation. The neoclassical answer is no.

## Related Study Guides

- [26.2 The Policy Implications of the Neoclassical Perspective](/principles-econ/unit-26/2-policy-implications-neoclassical-perspective/study-guide/jKspLoPGfYvin1If)

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