Macroeconomic Policy Conflicts and the Phillips Curve: Question 4

Worked solution

Part (a): Why demand-side policy alone risks a trade-off

The short-run Phillips curve plots an inverse relationship between the rate of unemployment and the rate of inflation: for a given set of inflation expectations, lower unemployment is only achieved at the cost of higher inflation, and vice versa. Demand-side policy (an interest rate cut, a tax cut or higher government spending) reduces unemployment by raising aggregate demand, which increases output and the demand for labour. However, as aggregate demand rises towards (or beyond) the economy’s existing productive capacity, firms find it harder to expand output further without bidding up wages and prices for increasingly scarce resources. This creates demand-pull inflationary pressure, so the same policy that lowers unemployment simultaneously risks raising inflation, a straightforward movement along the short-run Phillips curve.

Part (b): Can supply-side policy avoid this conflict?

The case that supply-side policy can reduce the conflict. Supply-side policies (for example government-funded education and training, subsidies for research and development, tax incentives for business investment, or reforms that improve labour market flexibility) work by raising the economy’s productive capacity and by reducing structural and frictional unemployment directly (making unemployed workers more employable and better matched to available vacancies). Because these policies increase the supply side of the economy rather than adding to demand, they can allow unemployment to fall without generating the demand-pull inflationary pressure that comes from a purely demand-side expansion. In effect, successful supply-side policy can lower the natural rate of unemployment itself, shifting the vertical long-run Phillips curve to the left, so that a lower unemployment rate becomes consistent with stable inflation in the long run, a genuine reduction in the inflation-unemployment trade-off rather than just a movement along it.

Limitations of relying on supply-side policy. Several factors limit how far supply-side policy alone can resolve the conflict:

• Long time lags. Education and training programmes, infrastructure investment and research incentives typically take years to raise productive capacity or improve workers’ skills. They cannot address unemployment that needs reducing in the short run, unlike demand-side policy, which acts more quickly.
• Cost and uncertain effectiveness. Supply-side spending is not guaranteed to succeed. Retraining programmes may not match the skills employers actually need, and some interventionist measures (such as large public infrastructure schemes) carry a real risk of government failure, wasting resources without durably raising capacity or lowering the natural rate of unemployment.
• The type of unemployment matters. Supply-side policy is best suited to reducing structural and frictional unemployment. If the unemployment a government is trying to reduce is instead demand-deficient (cyclical) (for example during a recession, where the underlying problem is a shortfall of aggregate demand rather than an inefficient labour market) supply-side measures alone will do little, and some demand-side stimulus may still be required, reintroducing at least part of the original trade-off.
• Other conflicts. Some market-based supply-side measures (for example cutting unemployment benefits to strengthen the incentive to work) can worsen income inequality, so avoiding one policy conflict (with inflation) may create another (with the objective of a more equal distribution of income).

Overall judgement. Supply-side policy can genuinely reduce the extent of the inflation-unemployment trade-off, particularly where unemployment is structural or frictional and the government is willing to accept a multi-year time frame for results. However, it cannot eliminate the conflict entirely: its long time lags and uncertain success mean it is a poor substitute for demand-side policy when unemployment is driven by a shortfall in demand, and some supply-side measures introduce conflicts of their own. In practice, most governments use supply-side policy alongside, rather than instead of, demand-side management, using it to ease, rather than remove, the conflict between low unemployment and low inflation.

Final answers

• (a) Demand-side policy lowers unemployment by raising aggregate demand, which also creates demand-pull inflation. A movement along the short-run Phillips curve
• (b) Supply-side policy can reduce the trade-off (by cutting the natural rate of unemployment without raising demand) but cannot eliminate it, given long time lags, cost/effectiveness uncertainty, its weak effect on demand-deficient unemployment, and the risk of creating other conflicts (e.g. with inequality)