Ch5. Fiscal Policy and Monetary Policy — How Governments and Central Banks Manage the Economy

Goals of Economic Stabilization Policy

Governments and central banks pursue two objectives simultaneously:

Economic stability: Prevent excessive expansion (inflation) or contraction (unemployment)
Sustainable growth: Long-run gains in productivity

Two policy tools:

Fiscal Policy: Government adjustment of taxes and spending
Monetary Policy: Central bank adjustment of money supply and interest rates

Fiscal Policy

Keynes and Aggregate Demand Management

John Maynard Keynes made a revolutionary argument during the Great Depression of the 1930s: “Markets cannot find equilibrium on their own. Government must intervene.”

The core of Keynesian economics: Aggregate demand (AD) drives the economy. In GDP = C + I + G + NX, when private demand (C, I) is insufficient, the government should increase G (government spending) to compensate.

Expansionary vs. Contractionary Fiscal Policy

Direction	Tools	When Used
Expansionary	G ↑, taxes ↓	During recession
Contractionary	G ↓, taxes ↑	During overheating or inflation

The Multiplier Effect

A $1 increase in government spending raises GDP by more than$ 1.

Tax Multiplier = −MPC / (1 − MPC)

Government Spending Multiplier = 1 / (1 − MPC)

(MPC = Marginal Propensity to Consume: the fraction of additional income spent on consumption)

Example: MPC = 0.8

Government spending multiplier = 1/(1−0.8) = 5
A $100 billion increase in government spending raises GDP by$ 500 billion

Intuition: Government spends $100B → household income rises$ 100B → consumption increases $80B → other households earn$ 80B → consumption increases $64B → … (chain reaction)

The Crowding-Out Effect

The limit of fiscal policy: If the government increases spending, demand for funds rises → interest rates rise → private investment falls.

Complete crowding out: The increase in government spending exactly offsets the decrease in private investment → no net change in aggregate demand (Classical view)

Partial crowding out: In reality, complete crowding out is rare, so fiscal policy retains some effectiveness

Monetary Policy

The Role of the Central Bank

The Federal Reserve (United States), European Central Bank (ECB), Bank of England, and other central banks:

Control the money supply
Set the benchmark policy interest rate
Oversee financial system stability

Tools of Monetary Policy

1. Open Market Operations

The central bank buys or sells Treasury securities.

Purchase of Treasuries → money supply increases → interest rates fall → lending and investment expand (expansionary)
Sale of Treasuries → money supply decreases → interest rates rise → lending and investment contract (contractionary)

2. Policy Rate Adjustment (Federal Funds Rate)

When the central bank sets the policy rate, market interest rates respond in a chain reaction.

Rate cut → lending rates ↓ → borrowing by firms and households increases → investment and consumption rise → GDP rises (expansionary)
Rate hike → lending rates ↑ → borrowing falls → investment and consumption fall → inflation is curbed (contractionary)

3. Reserve Requirement Adjustment

Banks must hold a fraction of deposits in reserve.

Lower reserve requirement → banks can lend more → money supply increases
Higher reserve requirement → banks lend less → money supply decreases

The IS-LM Model

The IS-LM model is a core macroeconomic tool that analyzes simultaneous equilibrium in the goods market and the money market.

The IS Curve (Goods Market Equilibrium)

IS (Investment-Saving): Combinations of the interest rate and national income at which the goods market is in equilibrium.

Slope: Downward-sloping — lower interest rates → more investment → higher GDP

IS curve shifts:

Government spending increases → IS shifts right (higher GDP at the same interest rate)
Taxes increase → IS shifts left

The LM Curve (Money Market Equilibrium)

LM (Liquidity-Money): Combinations of the interest rate and national income at which the money market is in equilibrium.

Slope: Upward-sloping — higher GDP → more money demand → higher interest rates

LM curve shifts:

Money supply increases → LM shifts right (lower interest rate at the same GDP)
Money supply decreases → LM shifts left

IS-LM Equilibrium and Policy Effects

Policy	Effect	IS/LM Change
Expansionary fiscal policy	GDP ↑, interest rate ↑	IS shifts right
Contractionary fiscal policy	GDP ↓, interest rate ↓	IS shifts left
Expansionary monetary policy	GDP ↑, interest rate ↓	LM shifts right
Contractionary monetary policy	GDP ↓, interest rate ↑	LM shifts left

The Liquidity Trap

A concept introduced by Keynes: when interest rates are extremely low, increasing the money supply no longer stimulates the economy.

Reason: When rates approach zero, investors prefer to hold cash rather than bonds (anticipating bond prices will fall). Additional money is absorbed by money demand → interest rates do not fall further.

Result: The LM curve becomes horizontal → monetary policy becomes ineffective; only fiscal policy works.

Japan’s “Lost Decades” (1990s onward) is the defining example: cutting rates to zero failed to revive the economy. In such a scenario, government fiscal spending becomes more effective.

Fiscal Policy vs. Monetary Policy: Practical Comparison

Attribute	Fiscal Policy	Monetary Policy
Authority	Government (Congress + Treasury)	Central bank (Federal Reserve)
Decision process	Requires legislative approval	Independent decision by monetary committee
Lags	Long inside lag	Long outside lag
Effect	Direct and strong	Indirect (interest rate channel)
Drawbacks	Deficit spending, crowding out	Liquidity trap, exchange rate effects

Optimal policy mix: During recession, expansionary fiscal + accommodative monetary policy. During inflation, contractionary fiscal + contractionary monetary policy.

Learning Checklist

Explain the tools and effects of expansionary and contractionary fiscal policy
Apply the multiplier formula to calculations
Explain the mechanism by which crowding out occurs
Explain how open market operations, the policy rate, and reserve requirements work
Explain the effect of each policy in the IS-LM model using a graph
Explain why monetary policy becomes ineffective in a liquidity trap

Key Concept Cards

Perfect Competition ★★★★★ : ① Many small firms ② Homogeneous product ③ Free entry and exit ④ Perfect information. Price taker (P = AR = MR). Long-run equilibrium: P = MC = ATC (zero economic profit). Achieves allocative efficiency.

Monopoly ★★★★★ : Price setter. MR < P (downward-sloping demand curve). Profit maximization: determine output where MR = MC, then read price from demand curve. Result: under-production, high price, deadweight loss. Memory tip: Monopoly: MR = MC (find output) → read price from demand curve (above MC)

Monopolistic Competition ★★★★ : ① Many firms ② Differentiated products ③ Free entry and exit. Short run: can earn above-normal profit like a monopolist. Long run: entry drives profit to zero, P = AC (but P > MC → inefficiency). Heavy advertising competition.

Oligopoly Models: Cournot, Bertrand, Stackelberg, Kinked Demand ★★★★★ : Cournot: quantity competition → Nash equilibrium. Bertrand: price competition → P = MC. Stackelberg: leader-follower model. Kinked demand: explains price rigidity (price ↑ → elastic demand; price ↓ → inelastic demand). Memory tip: Cournot = quantities, Bertrand = prices, Stackelberg = sequence

Price Discrimination ★★★★★ : 1st degree: charge each buyer their maximum willingness to pay (consumer surplus = 0). 2nd degree: quantity discounts (bundling). 3rd degree: segment markets (charge higher price in inelastic market).

Practice Quiz

Q. Monopoly profit maximization: how are output and price determined?

① Determine output (Q*) where MR = MC ② Plug Q* into the demand curve (AR) to find price (P*). P* > MC → deadweight loss occurs.

Q. In 3rd-degree price discrimination, which market gets the higher price — the inelastic or elastic market?

The inelastic market. The lower |PED|, the higher the price charged. Condition: MR₁ = MR₂ = MC.

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