Do I need to draw the LRAS curve on every Unit 3 FRQ graph?

Draw LRAS whenever the question involves output gaps, full employment, or long-run adjustment — which is most of Unit 3. LRAS is a vertical line at Y_f and is what lets you show whether equilibrium is in a recessionary or inflationary gap. When in doubt, include it and label it; a missing LRAS often costs a graph point.

Why is the tax multiplier smaller than the spending multiplier?

Government spending enters the economy in full as immediate demand. A tax change first alters disposable income, and households save part of it according to their MPS, so only the MPC portion is spent initially. That is why the tax multiplier is -MPC/1-MPC, always one less in magnitude than the spending multiplier 1/1-MPC.

How much writing does an 'explain' part require?

Give a clear cause-and-effect chain linking two variables, usually one to three sentences. For example, 'Government spending rises, which increases AD, raising real GDP and lowering unemployment.' You do not need extra background — just connect the cause to the effect the question asks about.

What is the most common way students lose easy FRQ points?

Unlabeled or mislabeled graphs. Forgetting axis labels, leaving curves unnamed, not showing the direction of a shift, or placing equilibrium on the wrong side of LRAS. Slow down on the diagram, label every curve and axis, and use arrows to show shifts clearly.

AP-MACRO-3-FRQ

U3 FRQ Practice

Master AP Macroeconomics Unit 3 free-response questions: draw correct AD-AS graphs, identify gaps, apply fiscal policy and multipliers, and earn every rubric point.

What you'll do in this lesson

A voice-first session with the Crimsora tutor on U3 FRQ Practice, then targeted practice and FRQs — with the tutor adapting to where you get stuck.

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What this lesson covers

The Unit 3 free-response question is where the College Board tests whether you can move fluidly between the AD-AS model, output gaps, and fiscal policy — all under time pressure. Rather than reciting definitions, you must draw a correct diagram, show shifts, and explain cause-and-effect chains that link a policy or shock to real GDP, the price level, and unemployment.

This guide is not a re-teach of the individual Unit 3 concepts. Instead it shows you how to attack the FRQ format: how graders read your graph, which verbs earn points, how to calculate multipliers cleanly, and the traps that quietly cost students easy points. Work the example and sample questions as if a clock is running.

How Unit 3 FRQs Are Structured and Scored

A Unit 3 FRQ typically opens with a scenario — an economy in recession, an inflationary boom, or a government considering a spending or tax change. Parts then chain logically: draw the current equilibrium, identify the gap, apply a shifter or policy, calculate a multiplier effect, and evaluate long-run adjustment.

Each part is worth a specific number of points, and graders use a rubric that rewards precise actions, not eloquence. A point is earned by doing exactly what the verb demands. The verbs matter enormously.

Verb	What graders want
Identify / What is	A one-word or one-number answer, no explanation needed
Calculate	Show the setup and the final number
Draw / Show	A correctly labeled graph with the correct shift
Explain / Explain how	A cause-and-effect chain connecting two variables

Misconception alert: writing a long paragraph for an "identify" question wastes time and earns nothing extra, while a bare number for a "calculate" question that says "show your work" can lose the point. Match effort to the verb. Answer parts in order and label them (a), (b), (c) exactly as the prompt does so nothing is missed.

Drawing the AD-AS Graph That Earns Points

Graph points are the most reliably won — and lost — points on a Unit 3 FRQ. The College Board requires a correctly labeled diagram. That means axes labeled Price Level (vertical) and Real GDP or Real Output (vertical axis is PL, horizontal is real GDP).

Always include, when relevant, the AD curve, SRAS curve, LRAS (a vertical line at full-employment output

Y_f

), the equilibrium point, and the equilibrium price level and output marked on the axes. When a shock or policy occurs, draw the new curve with an arrow showing the direction of the shift and label it (for example

AD_1 \to AD_2

Element	Common point-earning requirement
Axes	Labeled PL and Real GDP
Curves	AD, SRAS, LRAS labeled
Equilibrium	Point marked, PL and Y dropped to axes
Shift	Correct direction, new curve labeled
Gap	Distance between $Y_e$ and $Y_f$ shown

Misconception: students often forget LRAS or place equilibrium exactly at

Y_f

when the scenario describes a recession. If there is a recessionary gap, current equilibrium output must be drawn to the LEFT of

Y_f

; an inflationary gap sits to the RIGHT. Draw big and neat — a cramped graph invites grading errors against you.

Gaps, Fiscal Policy, and the Multiplier Chain

Once the diagram shows a gap, most FRQs ask for a fiscal policy remedy. A recessionary gap (

Y_e < Y_f

) calls for expansionary fiscal policy: increase government spending or cut taxes, shifting AD right. An inflationary gap (

Y_e > Y_f

) calls for contractionary policy: cut spending or raise taxes, shifting AD left.

Multiplier calculations frequently appear. Know the formulas cold.

Multiplier	Formula
Spending multiplier	$\frac{1}{1-MPC}$ or $\frac{1}{MPS}$
Tax multiplier	$-\frac{MPC}{1-MPC}$
Change in output	multiplier $\times$ initial change

MPC = 0.8

, the spending multiplier is

\frac{1}{1-0.8}=5

. A 100 increase in government spending raises real GDP by

5 \times 100 = 500

. A tax cut of the same size is weaker: the tax multiplier is

-\frac{0.8}{0.2}=-4

, so a 100 tax cut raises GDP by 400.

Exam tip: to close a gap of a known size, work backward. Required spending change

= \frac{\text{gap}}{\text{spending multiplier}}

. Explain in words that higher AD raises real GDP, lowers unemployment, and raises the price level — that cause-and-effect chain is usually its own point.

Long-Run Adjustment and Automatic Stabilizers

Later parts often test long-run self-adjustment or automatic stabilizers. If a government takes no action, an economy self-corrects: in a recessionary gap, high unemployment pushes nominal wages down, lowering production costs, shifting SRAS right until output returns to

Y_f

at a lower price level. In an inflationary gap, rising wages shift SRAS left, returning output to

Y_f

at a higher price level.

Automatic stabilizers — progressive taxes and transfer payments like unemployment benefits — change without new legislation. In a recession, tax revenue falls and transfers rise automatically, cushioning the drop in disposable income and AD. In a boom, the reverse dampens overheating. FRQs may ask how a stabilizer affects the budget balance: recessions automatically worsen the deficit, expansions shrink it.

Response	Mechanism	Speed
Discretionary fiscal policy	New law changes G or T	Slow (lags)
Automatic stabilizers	Existing taxes/transfers adjust	Immediate
Long-run self-adjustment	Wages/prices flex, SRAS shifts	Slowest

Common trap: confusing a SRAS shift (self-adjustment) with an AD shift (fiscal policy). When explaining self-correction, always move SRAS, never AD. And state the final price level relative to the start — graders check that you know self-adjustment changes PL, not just output.

Key terms

Recessionary gap.: When short-run equilibrium real GDP is below full-employment output ( $Y_e < Y_f$ ); associated with high unemployment.
Inflationary gap.: When short-run equilibrium real GDP exceeds full-employment output ( $Y_e > Y_f$ ); associated with rising prices.
Spending multiplier.: The factor by which a change in autonomous spending changes real GDP, equal to $\frac{1}{1-MPC}$ .
Tax multiplier.: The factor measuring the effect of a tax change on real GDP, equal to $-\frac{MPC}{1-MPC}$ ; smaller in magnitude than the spending multiplier.
LRAS.: Long-run aggregate supply, drawn as a vertical line at full-employment output, independent of the price level.
Automatic stabilizer.: A feature of the budget (like transfers or progressive taxes) that dampens business cycles without new legislation.
Long-run self-adjustment.: The process by which flexible wages and prices shift SRAS to return output to $Y_f$ without government action.
Expansionary fiscal policy.: Increases in government spending or tax cuts intended to shift AD right and close a recessionary gap.

Worked example

The economy of Vinland is in short-run equilibrium with real GDP below full employment. The marginal propensity to consume is 0.75. (a) Draw a correctly labeled AD-AS graph showing current equilibrium and the full-employment output level. (b) Identify the type of output gap. (c) The government wants to close a 400 billion recessionary gap using government spending. Calculate the required change in spending. (d) Explain what happens to the price level as a result.

Part (a): Draw axes with Price Level on the vertical and Real GDP on the horizontal. Draw downward-sloping AD, upward-sloping SRAS, and a vertical LRAS at

Y_f

. Because Vinland is below full employment, place the AD-SRAS intersection to the LEFT of LRAS. Mark equilibrium point

E_1

, dropping the price level

PL_1

and output

Y_1

to the axes.

Part (b): Since

Y_1 < Y_f

, this is a recessionary gap.

Part (c): First find the spending multiplier:

\frac{1}{1-MPC} = \frac{1}{1-0.75} = \frac{1}{0.25} = 4

. To close a 400 billion gap, required spending

= \frac{\text{gap}}{\text{multiplier}} = \frac{400}{4} = 100

billion. So the government must increase spending by 100 billion.

Part (d): The spending increase shifts AD right. As AD increases, both real GDP and the price level rise. Therefore the price level increases. On the graph you would show

AD_1 \to AD_2

intersecting SRAS at a higher output equal to

Y_f

and a higher price level

PL_2

Practice questions

An economy has an MPC of 0.9 and an inflationary gap of 300 billion. Which policy action would exactly close the gap?

Increase government spending by 30 billion
Decrease government spending by 30 billion
Decrease taxes by 30 billion
Increase government spending by 300 billion

Answer: Decrease government spending by 30 billion

An inflationary gap requires contractionary policy, so spending must fall (this rules out increases and tax cuts). The spending multiplier is

\frac{1}{1-0.9}=10

. Required change

= \frac{300}{10}=30

billion. Because the gap is inflationary, government spending must DECREASE by 30 billion, shifting AD left to return output to

Y_f

An economy is experiencing a recessionary gap, and the government takes no action. Explain how the economy returns to long-run equilibrium through self-adjustment, and state what happens to the price level.

Answer: SRAS shifts right; the price level falls.

With high unemployment during a recessionary gap, workers accept lower nominal wages. Falling wages reduce production costs, which shifts the SRAS curve to the right. SRAS keeps shifting until short-run equilibrium output returns to full-employment output

Y_f

. Because the AD curve does not move and SRAS shifts right along it, the new equilibrium occurs at a LOWER price level than before. A full-credit answer must move SRAS (not AD) and explicitly state the price level falls.

A government cuts taxes by 200 billion in an economy where MPC equals 0.8. Calculate the resulting change in real GDP and state the direction.

Answer: Real GDP increases by 800 billion.

Use the tax multiplier:

-\frac{MPC}{1-MPC} = -\frac{0.8}{0.2} = -4

. Change in GDP

= -4 \times (-200) = +800

billion. The tax CUT is a negative change in taxes, so multiplying by the negative tax multiplier gives a positive change in output. Real GDP rises by 800 billion. Note this is smaller than the 1000 billion effect an equivalent spending increase would produce, because part of the tax cut is saved.

FAQ

Do I need to draw the LRAS curve on every Unit 3 FRQ graph?: Draw LRAS whenever the question involves output gaps, full employment, or long-run adjustment — which is most of Unit 3. LRAS is a vertical line at $Y_f$ and is what lets you show whether equilibrium is in a recessionary or inflationary gap. When in doubt, include it and label it; a missing LRAS often costs a graph point.
Why is the tax multiplier smaller than the spending multiplier?: Government spending enters the economy in full as immediate demand. A tax change first alters disposable income, and households save part of it according to their MPS, so only the MPC portion is spent initially. That is why the tax multiplier is $-\frac{MPC}{1-MPC}$ , always one less in magnitude than the spending multiplier $\frac{1}{1-MPC}$ .
How much writing does an 'explain' part require?: Give a clear cause-and-effect chain linking two variables, usually one to three sentences. For example, 'Government spending rises, which increases AD, raising real GDP and lowering unemployment.' You do not need extra background — just connect the cause to the effect the question asks about.
What is the most common way students lose easy FRQ points?: Unlabeled or mislabeled graphs. Forgetting axis labels, leaving curves unnamed, not showing the direction of a shift, or placing equilibrium on the wrong side of LRAS. Slow down on the diagram, label every curve and axis, and use arrows to show shifts clearly.

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