Promoting Economic Growth

1. Governments promote economic growth using both demand-side and supply-side policies.
2. Demand-side policies raise aggregate demand to close a negative output gap, while supply-side policies expand productive capacity.
3. Which works best depends on whether the economy lacks demand or lacks capacity.

Demand-Side Policies Raise Demand

1. Expansionary fiscal policy raises government spending or cuts taxes; a £10bn public investment programme raises G and, via the multiplier, national income.
   1. Effectiveness: acts fast, within one to two years, and the multiplier can make the final rise in income larger than the initial injection. But it widens the fiscal deficit, may crowd out private investment if it raises interest rates, and mainly lifts prices rather than output once the economy nears full capacity.
2. Expansionary monetary policy cuts interest rates, so borrowing is cheaper and consumption and investment rise.
   1. Effectiveness: cheap for the government and flexible, but it works with a lag of roughly 12 to 18 months and is weak when confidence is low or rates are already near zero, since firms will not borrow to invest whatever the rate.
3. These work best with spare capacity, such as in a recession, where higher demand raises real output rather than just the price level (refer to 5.2 and 5.3 for in depth explanation).

Supply-Side Policies Expand Capacity

Supply side policy causes the aggregate supply curve to shift to right, allowing the real GDP to increase (refer to 5.4 for in depth explanation).

1. Investment incentives
   1. Tax breaks and capital allowances cut the cost of new machinery, so firms invest and capacity rises. Effectiveness: can lift investment within a year or two, but the fiscal cost per extra pound of investment is high because some firms would have invested anyway; it works best when the cost of capital, not weak demand, is the barrier.
2. Education and training
   1. These raise human capital, so output per worker rises and long-run capacity grows. Effectiveness: among the strongest long-run levers, but the payoff takes 10 years or more and the upfront cost is large; it works only if the quality of provision, not just enrolment, improves.
3. Infrastructure spending
   1. Better transport and digital networks cut firms' costs across the economy, raising productivity. Effectiveness: sizeable gains over 5 to 10 years, but capital costs are high and projects risk delay and misallocation; it works best where poor infrastructure is the binding constraint on output.
4. Tax and market reform
   1. Lower marginal taxes and deregulation sharpen incentives to work, hire and invest. Effectiveness: can improve incentives fairly quickly and at low direct cost, but the size of the growth boost is uncertain and it can widen inequality; it works best where regulation is genuinely excessive rather than protective.

How Effective Are Growth Policies?

1. For: with spare capacity a demand-side stimulus can raise real output quickly and, via the multiplier, by more than the initial injection, while supply-side reform can lift the trend growth rate permanently rather than for one cycle.
2. Against: supply-side policies suffer long time lags, so education or infrastructure may take years to raise growth.
3. Crowding out can weaken a debt-financed fiscal stimulus if higher government borrowing raises interest rates and squeezes private investment.
4. Demand-side policy near full capacity mainly raises the price level, not real output, risking inflation.
5. On balance, the effective choice depends on the cause of slow growth and the state of the economy. In a recession with a negative output gap, demand-side policy works fast and strongly; near full capacity it mostly raises prices, so lasting growth needs supply-side reform despite its long lags. The magnitude of the effect also depends on the size of the multiplier, the degree of crowding out, and whether the government has the fiscal space to fund it, so the strongest strategy usually combines both.