When the stock market tumbles, why do restaurants feel it? When the Fed cuts rates, why do construction cranes appear? Because the whole economy's spending is one connected object: aggregate demand — total spending on domestic output at each price level. It's the demand curve from micro, rebuilt at national scale, with new axes and completely different reasons for its slope. This is the first panel of the AD-AS model, the flagship graph of AP Macro — every policy question for the rest of the course gets drawn on it. Learn this curve's logic cold, because Units 3–6 are variations on shifting it.
Aggregate demand shows the total quantity of domestic goods and services demanded (real GDP) at each price level. Its components are exactly GDP's spenders:
AD = C + I + G + Xn
Axes matter: the y-axis is the price level (PL — think CPI/deflator), not "price"; the x-axis is real GDP (output, Y), not "quantity."
Micro's substitution and income effects don't work here — you can't substitute away from all goods, and when the price level falls, sellers' incomes fall too. The AP requires the three macro effects:
All three run through the components: lower PL → higher quantity of real output demanded — a movement along AD.
| Component | Shifts AD right when… | Shifts AD left when… |
|---|---|---|
| C | Consumer confidence/wealth rises (stocks, home values); personal taxes cut | Confidence/wealth falls; taxes raised |
| I | Interest rates fall*; expected returns/business optimism rise; business taxes cut | Rates rise; pessimism; investment taxed |
| G | Government purchases increase | Government purchases decrease |
| Xn | Foreign incomes rise; domestic currency depreciates | Foreign recession; currency appreciates |
Interest-rate changes caused by the price level are the movement-along mechanism (effect #2). Interest-rate changes from other causes — monetary policy (Lesson 10), loanable-funds events (Lesson 11) — shift AD. Ask why the rate moved. Here begins the real-interest-rate thread:* anything that changes the real rate changes investment, and anything that changes investment moves AD. Track that chain all course long.
Transfer payments and tax changes work through C (or I) — they shift AD indirectly, which is why the multiplier arithmetic in Lesson 8 treats them differently from G.
Apply It: For each event, movement or shift (and direction)? (1) The price level falls 3%. (2) A stock boom lifts household wealth. (3) The euro area booms, buying more U.S. exports. (4) Business pessimism spreads. → (1) movement along AD (down the curve); (2) AD right; (3) AD right; (4) AD left.
[GRAPH: Aggregate Demand
X-axis: Real GDP (Y)
Y-axis: Price level (PL)
Curve 1: AD, downward-sloping, labeled AD₁
Reading: at PL = 110, real GDP demanded = $18T; at PL = 100, $19T —
a movement ALONG AD₁ (wealth, interest-rate, exchange-rate effects)
Shift: consumer confidence surges → C rises at EVERY price level → entire
curve shifts right to AD₂ → at any given PL, more real output demanded]
AP labeling requirements: axes as PL and Real GDP (write them exactly — "P and Q" loses the point); curve labeled AD; shifts shown with a second labeled curve (AD₂) and an arrow. FRQ prompts say "show the effect on aggregate demand of…" — your job is (1) correct direction, (2) explicit arrow, (3) one sentence naming the component that moved. No equilibrium yet — that arrives when supply joins in Lesson 7.
1. A. The wealth (real-balances) effect: lower PL → money holdings buy more → C rises. B: micro substitution logic — invalid for all goods at once. C: costs belong to the supply curve. D: the money supply is set by the central bank, not the price level. E: G is policy-determined, not PL-determined.
Fix: AD's slope = wealth + interest-rate + exchange-rate effects — never micro substitution.
2. D. The price level is the y-axis variable: its changes move you along AD. A/B/C/E: taxes, optimism, G, and foreign incomes are all shifters.
Fix: PL changes → slide along; everything else that touches C, I, G, Xn → shift.
3. B. Falling wealth cuts consumption at every price level → AD left. A: home construction is in GDP, and the wealth channel works regardless. C: cheap houses don't outweigh the wealth destruction described. D: slope isn't affected by wealth levels. E: shifts don't wait for PL permission.
Fix: Wealth changes → C changes → AD shifts; direction follows the wealth.
4. E. Appreciation makes exports pricier abroad and imports cheaper at home → Xn falls → AD left. A: cheaper imports reduce net exports. B: exchange rates hit the Xn component directly. C: backwards. D: no slope change.
Fix: Appreciation ↓Xn ↓AD; depreciation ↑Xn ↑AD — chant it.
5. C. Business-tax cuts raise I; more G raises G — both push right. A: higher personal taxes push left, conflicting. B: rising rates push left. D: appreciation pushes left. E: falling stocks push left.
Fix: For "unambiguous" combos, check each event's sign; any conflict = indeterminate = not the answer.
6. B. Higher PL → more money needed for transactions → borrowing/rates up → investment down: quantity of output demanded falls. A: the discount rate is a policy choice, not automatic. C: direction reversed. D/E: neither is the mechanism.
Fix: The interest-rate effect is transactions demand for money, not central-bank action.
7. D. Tax cuts raise disposable income → C rises at every PL → AD right. A: nothing moved the price level. B: the cut shrinks the leakage — direction reversed. C: slope unchanged. E: shifts don't await PL changes.
Fix: Tax cuts and transfers operate through C: AD shifts right when households keep more income.
8. A. Booming partners buy more exports; depreciation makes them cheaper still — both raise Xn. B: expensive imports support net exports. C: the events reinforce, not conflict. D: no PL change described. E: shifts are defined at every price level.
Fix: Run each event through Xn separately, then add signs.
9. E. Higher expected returns → investment spending rises → AD right; I is the volatile, expectations-driven component. A: no PL change. B: saving logic doesn't reverse an investment boom. C: private spending needs no government trigger. D: expectations of returns move demand for capital, not the supply curve.
Fix: Investment runs on expected returns vs. the real interest rate — expectations up, I up, AD right.
10. C. Policy-driven rate increases raise borrowing costs → I (and interest-sensitive C) falls → AD left. A/B/D/E: each pushes AD right (C↑, I↑, Xn↑, C↑).
Fix: Rate changes from policy shift AD; only rate changes caused by the price level are the slope mechanism.
11. B. All three are the downward-slope mechanisms: lower PL → higher quantity of real GDP demanded. A: shifters are a separate list. C: AD isn't vertical — LRAS is (next lessons). D: slope logic isn't about permanent output. E: the multiplier is Lesson 8's story.
Fix: Slope = the three effects; shifts = changes in C, I, G, Xn — keep the two lists in separate mental drawers.
12. D. Transfers raise disposable income; spending out of it raises C. A: transfers are not government purchases. B: transfers are excluded from GDP as transfers — the induced consumption is not. C: some leakage to imports exists but the primary channel is C. E: deposits are saving, a leakage.
Fix: Transfers and tax cuts enter AD only through C — one step removed from G.
13. E. Confidence collapse = C falls at every PL = leftward shift, drawn with proper axes and labels. A: curves shift; they don't rotate vertical from confidence. B: no price-level change occurred. C: wrong direction. D: nonsense relabeling.
Fix: "Which graph shows…" questions are checklists: correct axes, correct curve, correct direction, labeled shift.
The economy of Delmar is experiencing the following simultaneous events: - The Delmar stock market rises 30%, significantly increasing household wealth. - The government of Delmar reduces its purchases of goods and services to shrink its deficit.
(a) Draw a correctly labeled graph of aggregate demand for Delmar, axes labeled, showing the effect of the stock-market boom ONLY. Label the initial curve AD₁ and the new curve AD₂.
(b) Identify which component of aggregate demand the stock-market boom affects, and explain the mechanism.
(c) Considering BOTH events together, can the direction of the overall change in aggregate demand be determined? Explain.
(d) Delmar's price level falls due to events abroad. Does this shift Delmar's AD curve? Explain in one sentence.
1. A. The wealth (real-balances) effect: lower PL → money holdings buy more → C rises. B: micro substitution logic — invalid for all goods at once. C: costs belong to the supply curve. D: the money supply is set by the central bank, not the price level. E: G is policy-determined, not PL-determined. Fix: AD's slope = wealth + interest-rate + exchange-rate effects — never micro substitution.
2. D. The price level is the y-axis variable: its changes move you along AD. A/B/C/E: taxes, optimism, G, and foreign incomes are all shifters. Fix: PL changes → slide along; everything else that touches C, I, G, Xn → shift.
3. B. Falling wealth cuts consumption at every price level → AD left. A: home construction is in GDP, and the wealth channel works regardless. C: cheap houses don't outweigh the wealth destruction described. D: slope isn't affected by wealth levels. E: shifts don't wait for PL permission. Fix: Wealth changes → C changes → AD shifts; direction follows the wealth.
4. E. Appreciation makes exports pricier abroad and imports cheaper at home → Xn falls → AD left. A: cheaper imports reduce net exports. B: exchange rates hit the Xn component directly. C: backwards. D: no slope change. Fix: Appreciation ↓Xn ↓AD; depreciation ↑Xn ↑AD — chant it.
5. C. Business-tax cuts raise I; more G raises G — both push right. A: higher personal taxes push left, conflicting. B: rising rates push left. D: appreciation pushes left. E: falling stocks push left. Fix: For "unambiguous" combos, check each event's sign; any conflict = indeterminate = not the answer.
6. B. Higher PL → more money needed for transactions → borrowing/rates up → investment down: quantity of output demanded falls. A: the discount rate is a policy choice, not automatic. C: direction reversed. D/E: neither is the mechanism. Fix: The interest-rate effect is transactions demand for money, not central-bank action.
7. D. Tax cuts raise disposable income → C rises at every PL → AD right. A: nothing moved the price level. B: the cut shrinks the leakage — direction reversed. C: slope unchanged. E: shifts don't await PL changes. Fix: Tax cuts and transfers operate through C: AD shifts right when households keep more income.
8. A. Booming partners buy more exports; depreciation makes them cheaper still — both raise Xn. B: expensive imports support net exports. C: the events reinforce, not conflict. D: no PL change described. E: shifts are defined at every price level. Fix: Run each event through Xn separately, then add signs.
9. E. Higher expected returns → investment spending rises → AD right; I is the volatile, expectations-driven component. A: no PL change. B: saving logic doesn't reverse an investment boom. C: private spending needs no government trigger. D: expectations of returns move demand for capital, not the supply curve. Fix: Investment runs on expected returns vs. the real interest rate — expectations up, I up, AD right.
10. C. Policy-driven rate increases raise borrowing costs → I (and interest-sensitive C) falls → AD left. A/B/D/E: each pushes AD right (C↑, I↑, Xn↑, C↑). Fix: Rate changes from policy shift AD; only rate changes caused by the price level are the slope mechanism.
11. B. All three are the downward-slope mechanisms: lower PL → higher quantity of real GDP demanded. A: shifters are a separate list. C: AD isn't vertical — LRAS is (next lessons). D: slope logic isn't about permanent output. E: the multiplier is Lesson 8's story. Fix: Slope = the three effects; shifts = changes in C, I, G, Xn — keep the two lists in separate mental drawers.
12. D. Transfers raise disposable income; spending out of it raises C. A: transfers are not government purchases. B: transfers are excluded from GDP as transfers — the induced consumption is not. C: some leakage to imports exists but the primary channel is C. E: deposits are saving, a leakage. Fix: Transfers and tax cuts enter AD only through C — one step removed from G.
13. E. Confidence collapse = C falls at every PL = leftward shift, drawn with proper axes and labels. A: curves shift; they don't rotate vertical from confidence. B: no price-level change occurred. C: wrong direction. D: nonsense relabeling. Fix: "Which graph shows…" questions are checklists: correct axes, correct curve, correct direction, labeled shift.
Exam tip: AD questions are two skills: (1) recite the three slope effects when asked "why downward," and (2) route every event through its component — C, I, G, or Xn — then move the curve. Write the component letter next to any FRQ shift; graders reward the named mechanism. Next lesson: the supply side of the flagship graph.