Monetary vs Fiscal Policy: Worked Examples

Monetary vs fiscal policy questions show up in nearly every macroeconomics assessment, and the marks split between three tasks: naming the tool, tracing how it reaches the economy, and drawing the AD-AS shift correctly. Students who miss marks usually get one of those three tasks wrong, not all of them. The worked examples below build from a single-policy scenario through a supply-shock case where the two policies conflict, with every step shown and the common error flagged after each solution.

Policy Tools at a Glance

Macroeconomics monetary vs fiscal policy divides all demand-management tools into two categories by who controls them. The distinction matters for exam answers because the transmission channels, lags, and constraints differ substantially.

Monetary Policy Tools

The central bank controls monetary policy. Its primary instrument in most economies since the 1990s is the policy interest rate (called the federal funds rate in the United States, the Bank Rate in the United Kingdom, or the main refinancing rate at the European Central Bank). When the central bank cuts this rate, commercial banks can borrow cheaply and pass lower rates on to households and firms. When it raises the rate, borrowing costs rise across the economy.

Three additional tools appear in advanced macroeconomics courses. Open market operations involve buying or selling government bonds to inject or withdraw base money. Reserve requirements set the fraction of deposits banks must hold rather than lend. Quantitative easing (QE) expands the central bank's balance sheet by purchasing long-dated assets when the policy rate approaches zero. Most exam questions focus on the policy rate channel because it dominates in practice. The OpenStax Principles of Macroeconomics chapter on central banks covers each tool with numerical examples.

Fiscal Policy Tools

The government controls fiscal policy through two levers: government spending (G) and taxation (T). Raising G injects demand directly into the economy. Cutting T raises household disposable income and business retained earnings, which then flow into consumption and investment. The net position, G minus T, is the budget balance: a deficit means G exceeds T (expansionary stance), and a surplus means T exceeds G (contractionary stance).

How to Answer Policy Questions Step by Step

A reliable five-step method covers every monetary vs fiscal policy step-by-step question. Use this structure for both short-answer and extended-response questions.

Step 1: Identify the Policy Type and Direction

Read the scenario and answer two sub-questions. First: who is acting? If the central bank cuts or raises a rate, this is monetary policy. If the government changes its budget, this is fiscal policy. Second: which direction? Cutting rates, buying bonds, or increasing G/cutting T is expansionary. Raising rates, selling bonds, or cutting G/raising T is contractionary.

Step 2: Trace the Transmission Channel

Write the causal chain explicitly. Examiners award marks for each correct link, so vague statements like “interest rates affect the economy” score less than a chain showing each step.

Step 3: Draw and Label the AD-AS Diagram

Draw the price level (P) on the vertical axis and real GDP (Y) on the horizontal axis. Mark three curves: SRAS (short-run aggregate supply, upward-sloping), LRAS (long-run aggregate supply, vertical at potential output Y*), and AD (downward-sloping). Label the initial equilibrium E1 where AD and SRAS cross. Draw the shift, arrow the new curve, and label it AD2. Mark E2 where AD2 and SRAS cross.

Step 4: State the Output and Price-Level Outcomes

Read E2 off the diagram. State whether real GDP is above potential (inflationary gap), below potential (recessionary gap), or at potential. State whether the price level rose or fell. A single sentence covers this: “Real GDP rises from Y1 to Y2, above the potential output Y*, and the price level rises from P1 to P2, indicating an inflationary gap.”

Worked Example 1: Expansionary Monetary Policy

This first example covers the standard monetary policy transmission question. It appears in introductory macroeconomics courses across every curriculum framework.

Setup and Question

Scenario: A national economy enters a recession. Real GDP falls 2% below potential output. The unemployment rate rises to 7.5%. The central bank responds by cutting its policy interest rate from 4.5% to 2.5%.

Question:Using the AD-AS model, explain how the central bank's action is expected to affect real GDP and the price level in the short run. (8 marks)

Full Solution

Step 1 (identify). The central bank cuts the policy rate. This is expansionary monetary policy.

Step 2 (transmission chain). The policy rate cut of 200 basis points reduces the rate at which commercial banks borrow from the central bank. Commercial banks lower mortgage rates, personal loan rates, and business lending rates. Households face lower mortgage repayments; their disposable income effectively rises. Firms face a lower cost of capital; the net present value of investment projects rises, so investment spending increases. The exchange rate may depreciate as domestic interest rates fall relative to foreign rates, making exports cheaper and imports more expensive, adding further to net export demand. Aggregate demand rises.

Step 3 (AD-AS shift). The AD curve shifts to the right, from AD1 to AD2. The SRAS curve does not shift because wages and input costs are unchanged in the short run; only demand has changed.

Step 4 (outcomes). The new short-run equilibrium E2 lies at a higher real GDP and a higher price level. Because the economy started 2% below potential, the rightward AD shift moves output closer to potential output Y*. If the shift is calibrated correctly, Y2 approaches Y* without creating an inflationary gap. The price level rises modestly from P1 to P2.

Worked Example 2: Contractionary Fiscal Policy

This second example covers a contractionary fiscal scenario. It tests the fiscal multiplier, crowding-out awareness, and the ability to read an AD shift in the recessionary direction.

Setup and Question

Scenario: An economy is operating above potential output with inflation running at 5.2% against a 2% target. The government announces a reduction in public expenditure of $40 billion and an increase in income tax rates that raises revenue by $20 billion. The MPC for the economy is 0.75.

Question (two parts):

1. Calculate the expected change in aggregate demand from the spending cut alone, assuming a simple fiscal multiplier.
2. Using the AD-AS model, explain the expected short-run and long-run effects on output and the price level.

Full Solution

Part 1 (calculate).

The spending multiplier equals 1 / (1 - MPC) = 1 / (1 - 0.75) = 1 / 0.25 = 4.

The change in government spending is -$40 billion (a cut). The change in aggregate demand equals the multiplier times the spending change: 4 × (-$40 billion) = -$160 billion.

The tax multiplier is slightly smaller: -(MPC / (1 - MPC)) = -(0.75 / 0.25) = -3. The tax rise of +$20 billion changes AD by (-3) × (+$20 billion) = -$60 billion.

Combined AD change from both measures: -$160 billion - $60 billion = -$220 billion. The AD curve shifts left by $220 billion.

Part 2 (AD-AS explanation).

Short run. AD shifts left from AD1 to AD2. The economy started above Y* with an inflationary gap. The leftward AD shift brings the short-run equilibrium E2 closer to potential output. Real GDP falls from its above-potential level, and the price level falls from above-target to closer to target. The recessionary pressure reduces the inflationary gap.

Long run. If the fiscal contraction brings AD2 through potential output Y*, the long-run equilibrium sits on LRAS at the full-employment level with a lower, more stable price level. If the cut overshoots, AD2 falls below Y*, creating a recessionary gap and requiring the government to loosen policy again or wait for wages to adjust downward (shifting SRAS right over time).

Worked Example 3: Policy Mix Under Supply Shock

This third example is the hardest type of macroeconomics monetary vs fiscal policy practice problem. A negative supply shock creates stagflation: falling output and rising inflation simultaneously. Any single demand-side policy faces a direct trade-off.

Setup and Question

Scenario: A global supply chain disruption raises input costs for manufacturers across the economy. SRAS shifts left by a significant amount. Real GDP falls 3% below potential output. The inflation rate rises from 2% to 6.5%.

Question: Evaluate whether monetary policy or fiscal policy is the more appropriate response to this supply shock. In your answer, refer to the AD-AS model and discuss the key trade-off.

Full Solution

Identify the shock type. A supply-side cost-push shock shifts SRAS left (not AD). The new short-run equilibrium has both lower output and a higher price level: the classic stagflation position. No demand-side policy can restore both objectives simultaneously.

The trade-off. If the central bank cuts rates (expansionary monetary policy) or the government raises spending (expansionary fiscal policy), AD shifts right. Output recovers toward Y*, but the price level rises further, worsening the already-high inflation. If instead the central bank raises rates or the government cuts spending (contractionary policy), inflation falls, but the output loss deepens.

Which policy is more appropriate? Most central banks and academic frameworks treat a persistent supply shock as a case where monetary policy prioritizes inflation first. The MIT OpenCourseWare Principles of Macroeconomics course materials on supply shocks note that credible anti-inflation commitment from central banks prevents wage-price spirals from embedding the shock permanently. Fiscal policy is then directed at protecting the most vulnerable households through targeted transfers, rather than blanket stimulus that feeds through to prices.

The AD-AS diagram for this scenario differs from the first two examples. SRAS shifts left (cost-push shock), and the policy response determines whether AD shifts in response. Draw two sub-scenarios on the same axis: one with a rightward AD shift (output recovers, inflation worsens) and one with no AD shift or a modest leftward AD shift (inflation targeted, output stays depressed short-term).

Common Errors That Cost Marks

The same patterns show up in every round of macroeconomics exam marking. Fixing these before your assessment adds marks without requiring additional content knowledge.

If you want to build the problem-solving fluency to avoid these errors under time pressure, practiced retrieval across different policy scenarios does more than any single re-reading of your lecture notes. The game theory worked examples post applies the same step-by-step method to strategic interaction problems, and the t-test worked examples post shows the same structure for quantitative hypothesis testing.

For a broader set of subject-specific practice problems and calculators, the university subject calculators hub has tools for quantitative economics and statistics that let you check your working numerically.

If you want an AI tutor that can generate additional monetary vs fiscal policy practice problems at your level, explain where your reasoning goes wrong, and walk through the AD-AS diagram step by step:

Key Takeaways

1. Monetary policy is set by the central bank (interest rates, open market operations, QE). Fiscal policy is set by the government (government spending G and taxation T). Never attribute rate decisions to the government in an exam answer.
2. Both expansionary monetary and expansionary fiscal policy shift AD to the right in the AD-AS model, raising output and the price level in the short run. Both contractionary versions shift AD left.
3. Write the full transmission chain for every policy question. Monetary: rate cut, lending costs fall, investment and consumption rise, net exports may rise, AD shifts right. Fiscal: G rises or T falls, disposable income or direct spending rises, consumption and G feed into expenditure identity, AD shifts right.
4. The fiscal spending multiplier equals 1 / (1 - MPC). The tax multiplier equals -(MPC / (1 - MPC)), which is smaller in absolute terms because tax changes affect AD only through the spending fraction households choose not to save.
5. A supply shock (SRAS shifts left) creates a genuine policy trade-off. Expansionary policy recovers output but worsens inflation. Contractionary policy fights inflation but deepens the output loss. State this conflict explicitly rather than proposing a single clean solution.
6. Crowding out limits fiscal policy when the economy operates near full capacity and interest rates are responsive to deficit spending. It is weaker in a recession with significant slack and near-zero rates.
7. Always draw LRAS on the AD-AS diagram, label Y*, and compare the new equilibrium to Y* to determine whether an inflationary gap or recessionary gap exists. Missing LRAS is the single most common diagram error in macroeconomics exam marking.

For a deeper look at macroeconomic measurement alongside these policy tools, the GDP calculation worked examples post covers the expenditure approach, income approach, and output approach in the same step-by-step format. The university resources hub has additional study tools for economics and other subjects.

For economics modules where grade calculations matter, the grade calculators hub has tools to track your module standing and calculate what you need on upcoming assessments.