Macroeconomics & Inflation

Edexcel Specification

Aggregate Demand

Aggregate demand is the total planned spending on goods and services in an economy at a given price level over a given time period.

AD = C + I + G + (X − M)

The Multiplier Effect
An initial injection into the economy (e.g., government spending) creates a chain reaction of additional spending. The multiplier = 1/(1 − MPC) = 1/MPS + MPT + MPM. If MPC = 0.8, the multiplier = 5: a £10m injection creates £50m of additional national income. Leakages (savings, taxes, imports) reduce the multiplier's size.

Types of Inflation

Demand-Pull Inflation

Caused by AD increasing faster than AS. "Too much money chasing too few goods." AD shifts right — price level rises.

Causes: Lower interest rates, increased consumer confidence, government spending increases, tax cuts, weaker exchange rate (exports cheaper), credit availability.

Diagram: AD shifts right along an upward-sloping SRAS curve.

Cost-Push Inflation

Caused by increases in production costs that shift SRAS left. Output falls while prices rise (can lead to stagflation).

Causes: Rising oil/commodity prices, wage increases above productivity growth, higher import prices (weaker £), increased business taxes, supply chain disruptions.

Diagram: SRAS shifts left — both higher prices and lower real output.

Consequences of Inflation

For Consumers

Reduces purchasing power if wages don't keep up. Erodes value of savings. Creates uncertainty — harder to plan. Redistributes wealth from savers to borrowers. Shoe-leather and menu costs.

For Firms & Economy

Reduces international competitiveness (exports more expensive). Creates investment uncertainty. Fiscal drag (pushes people into higher tax brackets). But: moderate inflation can signal healthy growth.

Macroeconomic Policy Tools

Monetary Policy

Controlled by the Bank of England (independent since 1997). Target: CPI inflation at 2%.

Interest rates: ↑ rates → ↓ borrowing, ↑ saving, ↓ C & I → ↓ AD → ↓ inflation

QE: Bank buys government bonds → ↑ money supply, ↓ long-term rates → ↑ C & I

Strengths: Independent, flexible, quick to implement

Weaknesses: Time lags (18-24 months), blunt instrument, liquidity trap

Fiscal Policy

Government decisions on taxation and public spending. Set in annual Budget.

Expansionary: ↑ G and/or ↓ T → ↑ AD → ↑ GDP (but ↑ budget deficit)

Contractionary: ↓ G and/or ↑ T → ↓ AD → ↓ inflation (but ↓ GDP)

Strengths: Targeted (can focus on specific groups/regions), multiplier effect

Weaknesses: Political influence, time lags, crowding out, national debt concerns

Supply-Side Policies

Policies that increase the productive capacity of the economy (shift LRAS right).

Market-based: Deregulation, privatisation, trade union reform, lower corporation tax

Interventionist: Education/training investment, infrastructure spending, R&D subsidies

Strengths: Address root causes, ↓ inflation + ↑ growth simultaneously

Weaknesses: Very long time lags (5-10 years), expensive, uncertain outcomes

The Phillips Curve

The Phillips curve shows an inverse relationship between unemployment and inflation — suggesting a trade-off between the two objectives.

Short-Run Phillips Curve

Shows the trade-off: reducing unemployment via expansionary policy causes higher inflation. Moving along the curve represents this trade-off. A shift in the SRPC occurs when expectations change.

Long-Run Phillips Curve

The monetarist view: in the long run, the Phillips curve is vertical at the Natural Rate of Unemployment (NRU). There is no trade-off — attempts to reduce unemployment below the NRU only cause accelerating inflation.

Edexcel exam tip: When evaluating macro policy, always discuss: (1) which component of AD/AS it affects, (2) short-run vs long-run impact, (3) time lags, (4) the trade-off (e.g., Phillips curve), (5) other objectives affected. Use the AD/AS diagram AND the Phillips curve together in your answer for maximum marks.