Component 2: Macroeconomics - 2. Economic policy objectives - 2.8 The Phillips Curve — OCR A-Level Economics
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- Natural rate of unemployment; non-accelerating inflation rate of unemployment (NAIRU)
Component 2: Macroeconomics - 2. Economic policy objectives - 2.8 The Phillips Curve exam tips
Quick Revision Summary (Key Takeaway)
The Phillips curve illustrates the macroeconomic relationship between inflation and unemployment, contrasting the short-run trade-off with the vertical long-run curve at the natural rate of unemployment. Understanding this concept is critical for evaluating monetary and fiscal policy conflicts under the OCR A-Level specification.
Topic Overview
The Phillips curve topic examines the fundamental conflict between two core macroeconomic objectives: maintaining low, stable inflation and achieving full employment. Originating from A.W. Phillips' empirical study of UK wage rates and unemployment, the theory was later developed by modern monetarists to distinguish between short-run cyclical fluctuations and long-run equilibrium.
Within the OCR A-Level specification, mastering this topic enables students to rigorously evaluate monetary and fiscal policy interventions. It bridges key macroeconomic models including AD/AS, the natural rate of unemployment, and expectations theory, providing a theoretical foundation for understanding policy limits and stagflation.
Key Concepts
- →Short-Run Phillips Curve (SRPC): Shows an inverse trade-off between the rate of inflation and the rate of unemployment.
- →Long-Run Phillips Curve (LRPC): A vertical line positioned at the Natural Rate of Unemployment (NRU/NAIRU), indicating no long-run trade-off.
- →Expectations-Augmented Phillips Curve: The hypothesis that changing inflation expectations shifts the SRPC upwards or downwards.
- →Supply-Side Shocks: Exogenous cost increases (e.g. energy crises) that cause stagflation, shifting the SRPC outward.
- →Hysteresis: The phenomenon where extended periods of high cyclical unemployment permanently increase the natural rate of unemployment.
Examiner Tips
- 💡When drawing shifts of the SRPC, use arrows to show the direction of the shift and clearly annotate the initial and new equilibrium points on the LRPC.
- 💡Integrate the concept of the Non-Accelerating Inflation Rate of Unemployment (NAIRU) directly into 12-mark and 25-mark macroeconomic essays to access top-band Level 4 evaluation.
- 💡Contrast adaptive expectations (where workers catch up to past inflation) with rational expectations (where workers anticipate policy immediately, making the short-run trade-off negligible).
Common Mistakes
- Believing the long-run Phillips curve can be shifted permanently to the left by continuous monetary expansion; demand-side stimulus only accelerates inflation in the long run.
- Confusing the movement along an SRPC with a shift of the SRPC; changes in aggregate demand move the economy along an existing SRPC, whereas changes in expectations or supply costs shift the SRPC.
- Assuming the natural rate of unemployment is zero; NAIRU incorporates frictional and structural unemployment consistent with stable inflation.
Revision Plan
- 1Day 1: Master the origins and mechanics of the original SRPC, including correct axis labelling and economic rationale.
- 2Day 2: Study the monetarist critique, the role of money illusion, and the derivation of the vertical LRPC.
- 3Day 3: Practice drawing and explaining outward and inward shifts of the SRPC caused by supply-side shocks and expectations.
- 4Day 4: Connect the Phillips curve framework to real-world UK economic policy dilemmas, such as the 1970s stagflation and post-2008 trends.
- 5Day 5: Complete timed OCR-style essay questions evaluating whether central banks should prioritise inflation over employment.
Exam Question Types
- 📋Data Response (4-6 marks): Interpreting graphs or tables of UK CPI inflation and claimant count rates to identify whether an empirical Phillips trade-off exists.
- 📋Context/Extract Questions (8-12 marks): Explaining how cost-push pressures or policy changes shift the SRPC.
- 📋Extended Evaluation Essays (25 marks): Assessing the effectiveness of demand-side versus supply-side policies in resolving macroeconomic policy trade-offs.
Command Word Expectations (OCR)
Explain
Set out the economic theory step by step using logical chains of reasoning and appropriate economic diagrams, with no need for balanced evaluation.
Evaluate
Provide a balanced argument examining both sides (e.g. short-run validity vs long-run breakdown of the trade-off), supported by diagrams and culminating in an evidence-based final judgement.
Analyse
Examine the theoretical linkages in detail (e.g. how an increase in AD creates derived demand for labour, reduces spare capacity, bids up wages, and accelerates inflation).
How Students Lose Marks (Examiner Pitfalls)
Pitfall: Confusing the Short-Run Phillips Curve (SRPC) trade-off with the Long-Run Phillips Curve (LRPC) and claiming that expansionary demand-side policies can permanently reduce unemployment.
❌ Weak Answer (Loses Marks):The government can just use expansionary fiscal policy to lower unemployment permanently, but inflation will rise along the curve.
Example improved answer:In the short run, expansionary policy stimulates aggregate demand, moving the economy up the SRPC to lower unemployment at the cost of higher demand-pull inflation. However, workers incorporate higher price levels into their adaptive or rational expectations, demanding higher nominal wages. This shifts the SRPC outwards (upwards), returning unemployment to the Non-Accelerating Inflation Rate of Unemployment (NAIRU) along the vertical LRPC at a permanently higher inflation rate.
Examiner Tip: Always draw both the SRPC and LRPC when evaluating long-term policy impacts to demonstrate understanding of expectations-augmented models.
Pitfall: Mislabelling axes on Phillips curve diagrams by using price level and real GDP instead of inflation rate (%) and unemployment rate (%).
❌ Weak Answer (Loses Marks):A diagram showing Aggregate Demand (AD) and Short-Run Aggregate Supply (SRAS) on axes labelled Price Level vs Real National Output.
Example improved answer:A correctly labelled Phillips curve diagram featuring 'Inflation Rate (%)' on the vertical y-axis and 'Unemployment Rate (%)' on the horizontal x-axis, clearly indicating the natural rate of unemployment at the vertical LRPC.
Examiner Tip: Never confuse AD/AS axes with Phillips curve axes. Doing so instantly invalidates analytical diagram marks in OCR exams.
Step-by-Step Worked Solutions
Question: Evaluate the view that there is an inevitable trade-off between inflation and unemployment. (12 marks)
- 1.Step 1: Define the original Phillips curve and explain the short-run inverse relationship (demand-pull pressures lower cyclical unemployment but raise the inflation rate).
- 2.Step 2: Analyse the Friedman-Phelps expectations-augmented critique, explaining how shifts in the SRPC occur due to revised inflation expectations, creating a vertical LRPC at the NAIRU.
- 3.Step 3: Introduce supply-side policies as an evaluative counter-argument, showing how labour market reforms can shift the LRPC inward, reducing both structural unemployment and inflation.
- 4.Step 4: Provide a synthesised judgement: the trade-off exists in the short run under demand management, but dissolves in the long run unless structural supply-side intervention occurs.
Final Answer: A short-run trade-off exists due to cyclical demand adjustments, but in the long run the Phillips curve is vertical at the NAIRU; sustained reductions in both require supply-side policies.
Question: Explain two factors that could cause the Short-Run Phillips Curve to shift outwards to the right. (4 marks)
- 1.Step 1: Identify factor 1 (e.g. an increase in inflation expectations or an adverse supply-side shock such as a sharp spike in imported oil prices).
- 2.Step 2: Explain how this raises costs of production across firms, causing cost-push inflation and higher unemployment simultaneously (stagflation).
- 3.Step 3: Identify factor 2 (e.g. an increase in structural labour market frictions or trade union power).
- 4.Step 4: Explain how this raises wage demands at every level of employment, shifting the entire SRPC upward/rightward.
Final Answer: The SRPC shifts outward due to higher inflation expectations/cost-push supply shocks and structural labour market rigidities that increase wage claims at any given unemployment rate.
Active Recall Memory Test
What are the exact axis labels for a Phillips curve diagram?
Key Fact: Vertical axis: Inflation Rate (%). Horizontal axis: Unemployment Rate (%).
What does the vertical Long-Run Phillips Curve (LRPC) represent?
Key Fact: The Natural Rate of Unemployment (or NAIRU), showing no trade-off between inflation and unemployment in the long run.
What causes an inward shift of the Long-Run Phillips Curve?
Key Fact: Effective supply-side policies that reduce structural or frictional unemployment, such as retraining schemes or labour market deregulation.
What is the difference between adaptive and rational expectations regarding the SRPC?
Key Fact: Adaptive expectations adjust with a lag based on past inflation, creating a temporary SRPC trade-off, while rational expectations anticipate policy outcomes instantly, eliminating the short-run trade-off.
Frequently Asked Questions
Why did the traditional Phillips curve collapse during the 1970s?
During the 1970s, oil price shocks caused severe cost-push inflation while simultaneously slowing economic output. This resulted in stagflation—high inflation and high unemployment concurrently. This breakdown disproved the stable inverse trade-off of the original Phillips curve and proved that supply-side shocks shift the entire SRPC outwards.
What is the difference between the NRU and the NAIRU?
In practice at A-Level, the terms are often used interchangeably. Strictly speaking, the Natural Rate of Unemployment (NRU) is the equilibrium rate where the labour market clears of cyclical unemployment, whereas the Non-Accelerating Inflation Rate of Unemployment (NAIRU) is the specific unemployment rate consistent with a constant, stable rate of inflation.
Can the Long-Run Phillips Curve ever shift?
Yes, the LRPC shifts when there is a change in the natural rate of unemployment. Supply-side policies that improve geographical labour mobility, upgrade worker skills, or increase incentives to work will shift the LRPC to the left. Conversely, negative hysteresis effects or greater labour market rigidities will shift the LRPC to the right.
Does quantitative easing (QE) create a movement along or a shift of the Phillips curve?
In the short run, QE acts as expansionary monetary policy, boosting aggregate demand and moving the economy up along the existing SRPC to lower unemployment and higher inflation. Over time, as inflation expectations adjust, the SRPC shifts outward, returning the economy to the LRPC at a higher inflation rate.