Fiscal Policy and Automatic Stabilizers

Expansionary and Contractionary Fiscal Policy

Fiscal policy is the use of government spending ($G$) and taxes ($T$) to influence real GDP, employment, and the price level. In the US, Congress writes the laws and the President signs them.

Remember that $AD = C + I + G + (X - M)$. Fiscal policy shifts AD by changing $G$ directly or by changing taxes, which changes disposable income and therefore consumption ($C$).

Closing a Gap with the Multipliers

How big should the policy be? Use the multipliers from the Spending Multipliers page. With $MPC$ as the marginal propensity to consume:

The tax multiplier is smaller in size because households save part ($MPS = 1 - MPC$) of a tax change, so only the $MPC$ share of it gets spent in the first round. The negative sign means a tax increase lowers GDP.

To close a gap (ignoring price-level changes, as the exercises do):

Here "gap" is the amount real GDP must change to reach full-employment output $Y_f$.

Combined packages

Policies are often mixed. Compute each part's effect separately and add:

where a tax cut means $\Delta T$ is negative, so the product is positive.

Why the Real World Differs

The formulas give a clean answer, but real policy is messier.

• Time lags. The recognition lag is the time it takes to notice a recession. The legislative lag is the time Congress needs to debate and pass a bill. The implementation lag is the time for money to actually be spent or paychecks to change. By the time the policy works, the economy may have already recovered.

• Crowding out. If the government borrows to fund a deficit, it raises demand in the loanable funds market and pushes up the real interest rate. Higher rates reduce private investment, so the net rise in AD is smaller than the multiplier predicts.

• Estimating the gap. Economists can only estimate $Y_f$ and the $MPC$, so policy can miss.

• Overshooting. If the stimulus is too big, AD moves past $Y_f$, creating an inflationary gap and rising prices.

Automatic Stabilizers

Automatic stabilizers are features of the tax and spending system that move the budget in the right direction during the business cycle without any new law or vote. They are "automatic" because the rules are already written: the economy's changes trigger them.

The two main examples:

1. Progressive income taxes. When incomes fall in a recession, people earn less and some move into lower tax brackets, so tax revenue falls faster than income. Disposable income falls by less than GDP. In an expansion, the reverse: revenue rises faster and slows spending.

2. Transfer payments such as unemployment insurance and SNAP. When layoffs rise, benefit payments rise automatically, which supports household spending. In an expansion, fewer people qualify and payments fall.

The picture shows the budget moving toward a deficit when GDP is low and toward a surplus when GDP is high. This happens automatically, and it works against the cycle: a deficit in a recession adds demand, and a surplus in a boom takes demand away.

Why a Proportional Tax Already Stabilizes

Even a proportional tax stabilizes. Suppose the tax is 20% of income and real GDP drops by $\$100$ billion.

Because taxes cushion the fall, the effective multiplier of the economy is smaller when taxes depend on income. That softens recessions and also softens booms.

Stabilizers vs. discretionary policy

For a mild recession, rely on automatic stabilizers: they act at once and avoid the risk of overshooting. For a deep recession, stabilizers alone are too weak, so Congress needs discretionary action, even with the lags, because the gap is large.

Back to the start: the quiet mall is helped automatically by unemployment checks and lower tax bills, and deliberately by new laws from Congress.

Summary