Macroeconomics Quiz: Is Curve Plus Monetary Policy Rule
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Is Curve Plus Monetary Policy RuleQuestion 1 of 20

An economy described by Y=1100−35rY = 1100 - 35r and r=0.02+0.75(π−0.025)+0.1(Y−1000)r = 0.02 + 0.75(\pi - 0.025) + 0.1(Y - 1000) is initially in equilibrium at potential output with 2.5% inflation. If government spending increases by 70 units, shifting the IS curve to Y=1170−35rY = 1170 - 35r, what is the final equilibrium output after monetary policy responds?

Output rises to approximately 1035 units as fiscal expansion is partially offset by monetary tightening through the output gap term
Output rises to exactly 1070 units because the central bank accommodates fiscal policy to maintain employment stability
Output rises to approximately 1045 units since the policy rule's inflation response dominates the output stabilization component
Output falls to approximately 985 units because the central bank's preemptive tightening more than offsets the fiscal stimulus
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Macroeconomics Quiz: Is Curve Plus Monetary Policy Rule

Practice Is Curve Plus Monetary Policy Rule in Macroeconomics with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

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Question 1

An economy described by Y=1100−35rY = 1100 - 35r and r=0.02+0.75(π−0.025)+0.1(Y−1000)r = 0.02 + 0.75(\pi - 0.025) + 0.1(Y - 1000) is initially in equilibrium at potential output with 2.5% inflation. If government spending increases by 70 units, shifting the IS curve to Y=1170−35rY = 1170 - 35r, what is the final equilibrium output after monetary policy responds?

  1. Output rises to approximately 1035 units as fiscal expansion is partially offset by monetary tightening through the output gap term (correct answer)
  2. Output rises to exactly 1070 units because the central bank accommodates fiscal policy to maintain employment stability
  3. Output rises to approximately 1045 units since the policy rule's inflation response dominates the output stabilization component
  4. Output falls to approximately 985 units because the central bank's preemptive tightening more than offsets the fiscal stimulus
Explanation: Initially: Y = 1000, π = 2.5%, r = 0.02. After fiscal expansion, assuming inflation remains at 2.5% in the short run, we solve: Y = 1170 - 35r and r = 0.02 + 0.1(Y - 1000). Substituting: Y = 1170 - 35[0.02 + 0.1(Y - 1000)] = 1170 - 0.7 - 3.5Y + 3500 = 4669.3 - 3.5Y. Solving: 4.5Y = 4669.3, so Y ≈ 1037. The fiscal expansion shifts IS rightward, but the output gap term in the policy rule causes the Fed to raise rates from 2% to about 5.7%, partially crowding out private investment. Choice B ignores the automatic monetary response. Choice C overemphasizes the inflation term when output gap dominates. Choice D incorrectly suggests net contractionary effect.

Question 2

In an economy with IS curve Y=950−30rY = 950 - 30r and monetary policy rule r=ρ+1.4(π−π∗)r = \rho + 1.4(\pi - \pi^*), where ρ\rho is the neutral real rate and π∗\pi^* is the inflation target, a permanent decrease in the neutral rate from 4% to 3% occurs due to demographic changes. If the inflation target remains at 2%, what happens to long-run equilibrium output?

  1. Output increases by 30 units because the lower neutral rate reduces the equilibrium real interest rate permanently (correct answer)
  2. Output decreases by 30 units as the central bank tightens policy to offset the expansionary effect of demographic changes
  3. Output remains unchanged at 830 units since the policy rule automatically adjusts to maintain the inflation target
  4. Output increases by 42 units due to the combined effects of lower neutral rates and reduced demographic pressures on investment
Explanation: In long-run equilibrium, inflation equals target (π = π*), so the policy rule gives r = ρ. Originally: r = 4%, Y = 950 - 30(4) = 830. After the neutral rate falls: r = 3%, Y = 950 - 30(3) = 860. Output increases by 30 units. The lower neutral rate reflects structural changes (demographics, productivity) that permanently reduce the equilibrium real rate. Choice B incorrectly suggests the Fed fights this structural change. Choice C ignores that the neutral rate change affects equilibrium output. Choice D uses an incorrect multiplier calculation.

Question 3

An economy in its long-run equilibrium experiences a sudden, permanent increase in government defense spending. Assuming the central bank follows an upward-sloping monetary policy rule, what is the most likely short-run impact on equilibrium output, the real interest rate, and private investment?

  1. Output increases, the interest rate increases, and investment decreases. (correct answer)
  2. Output increases, the interest rate is unchanged, and investment is unchanged.
  3. Output increases, the interest rate increases, and investment increases.
  4. Output is unchanged, the interest rate increases, and investment decreases.
Explanation: The increase in government spending shifts the IS curve to the right. This leads to a higher equilibrium level of output. As output increases, the central bank, following its upward-sloping MP rule, raises the real interest rate. The higher real interest rate, in turn, causes a reduction in private investment, an effect known as 'crowding out'.

Question 4

A government passes a deficit-financed tax cut for households. Simultaneously, the central bank, fearing the inflationary consequences, shifts its monetary policy rule to set a higher real interest rate for any given level of output. Based on the IS-MP model, what is the definite outcome of these combined policies?

  1. The real interest rate will increase, while the effect on output is ambiguous. (correct answer)
  2. Output will increase, while the effect on the real interest rate is ambiguous.
  3. Both output and the real interest rate will increase.
  4. Both output and the real interest rate will decrease.
Explanation: The tax cut is an expansionary fiscal policy, shifting the IS curve to the right. This tends to increase both output and the real interest rate. The central bank's action is a contractionary monetary policy, shifting the MP curve upward. This tends to decrease output and increase the real interest rate. Since both policies push the real interest rate up, it will definitely increase. However, the fiscal policy pushes output up while the monetary policy pushes output down, so the net effect on output is ambiguous and depends on the relative magnitudes of the shifts.

Question 5

Suppose a central bank follows a Taylor-type monetary policy rule: r=r∗+α(π−π∗)r = r^* + \alpha(\pi - \pi^*), where π∗\pi^* is the long-run inflation target. The central bank permanently lowers its inflation target π∗\pi^*. Holding current inflation π\pi and the natural rate of interest r∗r^* constant, how will this policy change be represented in the IS-MP diagram, and what is its short-run effect?

  1. A downward shift of the MP curve, leading to higher output and a lower real interest rate.
  2. An upward shift of the MP curve, leading to lower output and a higher real interest rate. (correct answer)
  3. A leftward shift of the IS curve, as the new policy reduces expected long-run growth.
  4. No change in the curves, as the long-run inflation target does not affect the short-run real interest rate.
Explanation: This question tests your understanding of Taylor rules and the IS-MP framework. When you see a Taylor rule equation, focus on how changes in the rule's parameters affect the actual interest rate the central bank sets. Let's work through what happens when the central bank lowers its inflation target π∗\pi^*. Looking at the Taylor rule r=r∗+α(π−π∗)r = r^* + \alpha(\pi - \pi^*), if π∗\pi^* decreases while current inflation π\pi stays constant, then (π−π∗)(\pi - \pi^*) increases. Since α>0\alpha > 0, this makes rr larger—the central bank sets a higher real interest rate. In the IS-MP diagram, the MP curve shows the real interest rate the central bank chooses for each output level. When the Taylor rule generates higher interest rates across all scenarios, the entire MP curve shifts upward. This higher interest rate reduces investment and consumption, moving the economy up along the IS curve to lower output. Looking at the wrong answers: (A) incorrectly suggests the MP curve shifts down—this would happen if the inflation target increased, not decreased. (C) misidentifies this as an IS curve shift, but the IS curve represents spending decisions by firms and households, which aren't directly affected by the central bank's target change. (D) is wrong because the Taylor rule clearly shows that changing π∗\pi^* does affect the current real interest rate when inflation differs from the target. Remember: In Taylor rule questions, always trace through the algebra first. A lower inflation target makes current policy more contractionary, shifting MP up and reducing output in the short run.

Question 6

Economic data for a closed economy reveals that in the last quarter, short-run equilibrium output increased while the real interest rate decreased. Which of the following single shocks is the most plausible explanation within the IS-MP framework?

  1. Consumers unexpectedly increased their savings rate due to pessimism about the future.
  2. The government increased its spending on infrastructure.
  3. A technological innovation increased firms' desired investment at every interest rate.
  4. The central bank lowered its target real interest rate. (correct answer)
Explanation: When analyzing changes in both output and interest rates simultaneously, you need to distinguish between movements along curves versus shifts of the curves themselves in the IS-MP framework. The IS curve shows combinations of output and interest rates where goods markets clear, while the MP curve represents monetary policy. The correct answer is D because when the central bank lowers its target real interest rate, the MP curve shifts down. This creates a new equilibrium at the intersection with the unchanged IS curve, resulting in both lower interest rates and higher output - exactly what the data shows. Let's examine why the other options don't work: A is incorrect because increased savings shifts the IS curve left (reduced consumption), which would decrease both output and interest rates - the interest rate change matches, but output should fall, not rise. B is wrong because increased government spending shifts IS right, raising both output and interest rates - output rises as observed, but interest rates should increase, not decrease. C fails because higher desired investment also shifts IS right, again increasing both output and interest rates rather than the observed pattern of higher output with lower rates. The key insight is that only monetary policy changes (MP curve shifts) can produce the combination of higher output and lower interest rates. Fiscal policy or spending behavior changes (IS curve shifts) move output and interest rates in the same direction, while the data shows them moving in opposite directions. Remember: when output and interest rates move in opposite directions, look for monetary policy explanations first.

Question 7

Analysis of a country's recent economic performance shows that its short-run equilibrium output has decreased, while the level of private investment has remained roughly constant. Which combination of shocks in the IS-MP model could explain this outcome?

  1. An expansionary monetary policy on its own.
  2. A positive shock to consumer confidence combined with a contractionary monetary policy.
  3. A contractionary fiscal policy on its own.
  4. A contractionary fiscal policy combined with an expansionary monetary policy. (correct answer)
Explanation: When analyzing economic shocks using the IS-MP model, you need to track how different policies affect both output and investment simultaneously. The IS curve represents equilibrium in the goods market, while the MP curve shows monetary policy's effect on real interest rates. The key insight here is that contractionary fiscal policy shifts the IS curve leftward (reducing output), while expansionary monetary policy shifts the MP curve downward (lowering interest rates). When combined, these opposing forces create a unique outcome: output falls due to reduced government spending, but lower interest rates prevent investment from declining significantly. Answer D correctly identifies this combination. The contractionary fiscal policy directly reduces aggregate demand and output, while the expansionary monetary policy keeps interest rates low enough to maintain investment levels roughly constant. Answer A is wrong because expansionary monetary policy alone would increase both output and investment by lowering interest rates. Answer B fails because positive consumer confidence would shift IS rightward (increasing output), and even if contractionary monetary policy partially offset this, investment would clearly fall due to higher interest rates. Answer C is incorrect because contractionary fiscal policy alone would reduce both output and investment—higher interest rates from reduced government borrowing would make investment more expensive. Remember that in IS-MP analysis, always consider the dual effects: fiscal policy primarily shifts IS (affecting output directly), while monetary policy shifts MP (affecting interest rates and investment). When outcomes seem contradictory—like falling output with stable investment—look for combinations of opposing policies rather than single shocks.

Question 8

Suppose an economy is initially at potential output. A wave of consumer pessimism, not offset by any policy change, causes a sharp fall in autonomous consumption. According to the IS-MP model with an upward-sloping MP curve, what is the role of the central bank's automatic policy response?

  1. It completely stabilizes output by lowering the interest rate enough to restore consumption to its original level.
  2. It deepens the recession by raising the real interest rate to fight potential deflation.
  3. It has no effect, as an automatic response requires a deliberate policy decision and shift of the MP curve.
  4. It mitigates the recession by lowering the real interest rate, which stimulates investment. (correct answer)
Explanation: When you encounter IS-MP model questions involving shocks and central bank responses, focus on distinguishing between automatic responses (movements along curves) and policy shifts (curve movements themselves). In this scenario, consumer pessimism reduces autonomous consumption, shifting the IS curve leftward. With an upward-sloping MP curve, the central bank automatically responds to changing economic conditions without shifting its policy rule. As output falls below potential, deflationary pressures emerge. The upward-sloping MP curve means the central bank systematically lowers real interest rates when inflation falls below target. This automatic interest rate reduction stimulates investment spending, partially offsetting the consumption decline and mitigating the recession's severity. Answer A is incorrect because the automatic response only partially stabilizes output—it doesn't fully restore consumption or return output to its original level. The central bank's response works through investment, not by directly fixing consumption. Answer B misunderstands the MP curve's slope: with an upward-sloping MP curve, the central bank lowers rates when facing deflationary pressure, not raises them. Answer C confuses automatic responses with discretionary policy changes. An automatic response means the central bank follows its existing policy rule (moving along the MP curve), while discretionary policy would shift the entire MP curve. Remember this key distinction: automatic central bank responses involve movements along the MP curve based on the bank's existing policy rule, while deliberate policy changes shift the entire curve. The upward slope means rates automatically fall when inflation drops below target.

Question 9

A banking crisis leads to a sharp increase in the credit risk premium that firms must pay to borrow for investment projects. In the IS-MP framework, where 'r' on the vertical axis is the central bank's policy rate, how does this shock affect the economy?

  1. It makes the IS curve steeper, as investment becomes less responsive to the policy rate.
  2. It shifts the MP curve up, as the central bank tightens policy to ensure financial stability.
  3. It shifts the IS curve to the left, reducing both output and the policy interest rate. (correct answer)
  4. It has no effect on the IS or MP curve, as the risk premium is a financial market phenomenon not captured in this model.
Explanation: When analyzing shocks in the IS-MP framework, you need to distinguish between changes that affect spending decisions (IS curve) versus monetary policy decisions (MP curve). A banking crisis that increases credit risk premiums creates a wedge between the policy rate and the actual borrowing costs firms face. The correct answer is C because higher credit risk premiums make investment projects less attractive at any given policy rate. If the central bank sets its rate at 3% but firms must now pay an additional 2% risk premium, their effective borrowing cost jumps to 5%. This reduces investment spending across the economy, shifting the entire IS curve leftward. In equilibrium, this leads to lower output and typically prompts the central bank to lower its policy rate to partially offset the shock. Option A incorrectly suggests the IS curve becomes steeper. The slope represents sensitivity to interest rate changes, but a risk premium shock shifts the entire relationship rather than changing this sensitivity. Option B wrongly assumes the central bank tightens policy during a banking crisis. While maintaining financial stability is important, central banks typically lower rates to counteract the contractionary effects of credit crunches. Option D misunderstands how risk premiums affect the real economy. Even though the MP curve shows the policy rate, changes in risk premiums directly impact investment decisions and thus shift the IS curve. Remember: in IS-MP analysis, always ask whether a shock primarily affects spending decisions (IS curve) or monetary policy decisions (MP curve). Credit market disruptions typically shift IS because they change borrowing conditions for spending.

Question 10

A student of macroeconomics, accustomed to the IS-LM model, is analyzing an economy using the modern IS-MP framework. The central bank in this economy conducts an open-market purchase of bonds. What is the correct analysis of this action's immediate effect in the IS-MP model?

  1. The action is an implementation tool to keep the real interest rate consistent with the MP rule, and does not in itself represent a policy shift. (correct answer)
  2. It shifts the MP curve down, as the increased money supply corresponds to a lower interest rate for any given level of output.
  3. It shifts the IS curve to the right, as lower interest rates from the bond purchase stimulate investment.
  4. It has no effect because the real interest rate is determined by the central bank's rule, and open market operations only affect the nominal rate.
Explanation: In the IS-MP framework, the central bank's policy is summarized by its rule for setting the real interest rate, represented by the MP curve. Open market operations are the technical means by which the central bank adjusts the money supply to achieve its interest rate target. Therefore, an open-market purchase is not a policy shock that shifts the MP curve; rather, it is the action taken to ensure the interest rate is at the level prescribed by the rule. A shift in the MP curve would only occur if the central bank changed its underlying rule or target.

Question 11

The government enacts a significant increase in public infrastructure spending, financed by borrowing. According to the standard IS-MP model with an upward-sloping MP curve, what is the expected short-run impact on the main components of GDP (Consumption, Investment, and Government Purchases)?

  1. Government purchases, consumption, and investment all increase.
  2. Government purchases increase, while consumption and investment both decrease.
  3. Government purchases increase, consumption increases, and investment decreases. (correct answer)
  4. Government purchases increase, investment decreases, and consumption remains unchanged.
Explanation: When you encounter IS-MP model questions about fiscal policy, focus on how government spending affects interest rates and how those rate changes ripple through the economy's components. In the IS-MP framework, increased government spending financed by borrowing shifts the IS curve rightward, raising both output and interest rates (moving up the upward-sloping MP curve). Here's how each GDP component responds: Government purchases increase directly since that's the policy action. Higher output boosts household incomes, leading to increased consumption. However, the rising interest rates make borrowing more expensive for businesses, reducing investment spending. This creates the classic "crowding out" effect where government borrowing displaces private investment. Looking at the wrong answers: Option A incorrectly suggests investment increases—this ignores that higher interest rates discourage business investment. Option B wrongly claims consumption decreases; while higher interest rates do discourage consumer borrowing, the income effect from increased output typically dominates in the short run, leading to higher consumption. Option D incorrectly states consumption remains unchanged, missing that higher income from expanded economic activity stimulates consumer spending. The correct answer is C: government purchases and consumption both rise while investment falls due to crowding out. Study tip: Remember the IS-MP "recipe" for deficit-financed fiscal expansion: government spending up directly, consumption up from higher income, investment down from higher interest rates. This crowding-out pattern appears frequently on macro exams, so always trace through both the income and interest rate effects when analyzing fiscal policy.

Question 12

Economists believe that investment in a certain economy depends not only on the real interest rate but also positively on the level of output (an 'accelerator' effect). How does this feature affect the properties of the IS curve and the impact of a contractionary monetary policy shock (an upward shift of the MP curve)?

  1. The IS curve becomes steeper, and the resulting fall in output is dampened.
  2. The IS curve becomes flatter, and the resulting fall in output is magnified. (correct answer)
  3. The IS curve's position shifts to the right, but its slope is unaffected.
  4. The IS curve is unaffected, but the monetary policy shock is less effective.
Explanation: This question tests your understanding of how the accelerator effect modifies the standard IS-MP model. The accelerator effect means that investment depends not just on interest rates, but also positively on current output levels - when the economy is doing well, firms invest more in anticipation of continued growth. When investment responds positively to output, this creates a feedback loop that amplifies changes in the economy. If output rises, investment increases, which further boosts output through the multiplier effect. Conversely, if output falls, investment drops, causing output to fall even more. This feedback mechanism makes the IS curve flatter because a given change in interest rates now produces a larger change in equilibrium output. With a flatter IS curve, contractionary monetary policy (an upward shift in the MP curve that raises real interest rates) becomes more potent. The higher interest rates reduce investment, which lowers output, which further reduces investment through the accelerator effect, magnifying the total decline in output. Option A incorrectly suggests the IS curve becomes steeper and dampens the output effect - this would be true if investment were negatively related to output, which contradicts the accelerator effect. Option C wrongly focuses on a shift rather than a slope change, while the accelerator effect fundamentally alters how sensitive equilibrium output is to interest rate changes. Option D incorrectly claims the IS curve is unaffected, missing that the accelerator effect directly changes the investment function that underlies the IS curve. Remember: when investment depends on output, economic shocks get amplified through feedback effects, making the IS curve flatter and monetary policy more powerful.

Question 13

A government research report is published, credibly forecasting lower long-term economic growth. As a result, households revise their expectations of future income downward and increase their current savings. In the IS-MP model, this will lead to:

  1. a rightward shift of the IS curve, as higher savings lead to more funds for investment.
  2. a leftward shift of the IS curve, resulting in lower output and a lower real interest rate. (correct answer)
  3. a downward shift of the MP curve, as the central bank preemptively eases policy to counter the negative news.
  4. a steepening of the IS curve, as consumption becomes less responsive to current income.
Explanation: The IS-MP model shows the relationship between output and interest rates in the short run. When you encounter scenarios about changed expectations affecting household behavior, focus on how this shifts the IS curve, which represents equilibrium in the goods market. When households expect lower future income, they increase current savings to smooth consumption over time. This means they reduce current consumption spending. Since the IS curve represents combinations of output and interest rates where planned spending equals actual output, reduced consumption shifts the entire IS curve leftward. At any given interest rate, total spending (consumption + investment + government) is now lower, so equilibrium output falls. The central bank typically responds by lowering rates to stimulate demand, moving the economy down along the new IS curve to a point with both lower output and lower real interest rates. Answer A incorrectly applies the loanable funds framework to the IS-MP model. While higher savings might increase funds available for lending, this doesn't directly shift IS rightward - the immediate effect is reduced consumption demand. Answer C confuses cause and effect; the MP curve shift would be the central bank's response, not the initial impact of changed expectations. The question asks about the direct result of household behavior changes. Answer D misunderstands what causes IS curve steepness. The slope depends on how sensitive investment is to interest rates, not how consumption responds to income changes. Remember: in IS-MP questions, always trace through the spending components first. Reduced consumption shifts IS left, regardless of what happens to savings in financial markets.

Question 14

The central bank announces a new policy framework that involves a more aggressive response to output gaps. In the IS-MP model, this is represented as a steepening of the upward-sloping MP curve. Subsequently, the economy experiences a wave of consumer optimism that shifts the IS curve to the right. Compared to the outcome under the old, less aggressive policy framework, the new framework will result in:

  1. a smaller increase in output and a larger increase in the real interest rate. (correct answer)
  2. a larger increase in output and a smaller increase in the real interest rate.
  3. a smaller increase in output and a smaller increase in the real interest rate.
  4. no change in output but a significantly larger increase in the real interest rate.
Explanation: A more aggressive response to output gaps means the central bank will raise the interest rate more sharply for any given increase in output, making the MP curve steeper. When the IS curve shifts to the right, it intersects the new, steeper MP curve at a point that is higher up (larger increase in r) and less far to the right (smaller increase in Y) than where it would have intersected the old, flatter MP curve. The aggressive policy dampens the output boom but at the cost of a sharper interest rate hike.

Question 15

Consider an economy operating at the zero lower bound (ZLB), where the central bank's policy rate cannot go any lower. A severe negative demand shock then shifts the IS curve far to the left. In this situation, how does the effectiveness of a subsequent fiscal expansion (e.g., increased government spending) compare to normal times (when not at the ZLB)?

  1. It has the same effectiveness, as the government spending multiplier is independent of monetary policy actions.
  2. It is less effective because consumers are more likely to save any additional income due to pessimistic expectations.
  3. It is more effective because the real interest rate does not rise, preventing the crowding out of private investment. (correct answer)
  4. It is completely ineffective because the economy is in a liquidity trap where only monetary policy can stimulate demand.
Explanation: This question tests your understanding of fiscal policy effectiveness under different monetary policy conditions, specifically at the zero lower bound (ZLB). When you encounter ZLB scenarios, focus on how the inability to lower interest rates further changes the typical fiscal-monetary policy interactions. At the ZLB, fiscal expansion becomes significantly more effective than in normal times. Here's why: Ordinarily, when the government increases spending, it must borrow money by issuing bonds. This increased demand for funds pushes up interest rates, which "crowds out" private investment as businesses find borrowing more expensive. However, at the ZLB, the central bank is committed to keeping rates at zero regardless of fiscal actions. This means the real interest rate cannot rise to choke off private investment, eliminating the crowding-out effect and making fiscal policy much more potent. Option A is wrong because the government spending multiplier definitely depends on monetary policy responses—it's much larger when monetary policy accommodates fiscal expansion. Option B incorrectly focuses on consumer psychology rather than the interest rate mechanism that's crucial here. While pessimistic expectations might affect consumption, this isn't the primary channel affecting fiscal multiplier size at the ZLB. Option D overstates the case—fiscal policy isn't completely ineffective, and monetary policy is actually constrained at the ZLB, not uniquely powerful. Remember this key insight: fiscal policy and monetary policy are most complementary at the ZLB. When you see ZLB questions, immediately think about how the inability to lower rates further changes normal policy trade-offs.

Question 16

Consider two economies, A and B, that are identical except that in Economy A, business investment is highly sensitive to changes in the real interest rate, while in Economy B, it is not. If both economies' central banks pursue an identical monetary easing by shifting the MP curve downward by 1 percentage point, what will be the result?

  1. Output will increase by more in Economy A than in Economy B. (correct answer)
  2. Output will increase by more in Economy B than in Economy A.
  3. The real interest rate will fall by more in Economy A than in Economy B.
  4. Output will increase by the same amount in both economies, but investment will rise more in Economy A.
Explanation: A higher sensitivity of investment to the real interest rate implies a flatter IS curve. In Economy A, the IS curve is flatter than in Economy B. When the MP curve shifts down by the same amount in both economies, the new equilibrium point on the flatter IS curve (Economy A) will be further to the right than the new point on the steeper IS curve (Economy B). Therefore, output will increase by more in Economy A.

Question 17

An economy experiences a sudden, temporary spike in energy prices, which causes a burst of inflation. The central bank, following its monetary policy rule which responds to inflation, adjusts its policy rate. How is this scenario best represented in the IS-MP model?

  1. The MP curve shifts upward, as the central bank raises the real interest rate to combat inflation, leading to a decrease in output. (correct answer)
  2. The IS curve shifts to the left, because higher energy prices reduce households' discretionary income.
  3. The economy moves along a stationary MP curve to a higher interest rate because output has increased.
  4. Neither curve shifts, as inflation is not explicitly represented on the axes of the standard IS-MP diagram.
Explanation: The IS-MP diagram plots the real interest rate versus output. While inflation is not on an axis, the central bank's policy rule often depends on it. An inflation spike, holding output constant, will cause the central bank to raise the real interest rate according to its rule (like a Taylor rule). This decision to set a higher rate for any given level of output is modeled as an autonomous policy tightening, which corresponds to an upward shift of the MP curve. This results in a movement along the IS curve to a new equilibrium with lower output.

Question 18

A newly elected government wants to increase short-run output to fulfill campaign promises but is concerned that doing so will raise interest rates and crowd out private investment. Which of the following policy combinations would be most effective at achieving higher output while keeping the real interest rate constant?

  1. An increase in government purchases only.
  2. A decrease in taxes combined with an upward shift in the central bank's policy rule.
  3. An increase in government purchases combined with a downward shift in the central bank's policy rule. (correct answer)
  4. A downward shift in the central bank's policy rule only.
Explanation: This question tests your understanding of how fiscal and monetary policy interact to influence output and interest rates. When you see a problem about achieving multiple macroeconomic goals simultaneously, think about how different policy tools can work together or against each other. To increase output while keeping interest rates constant, you need to counteract the typical interest rate effects of expansionary fiscal policy. Increased government purchases (expansionary fiscal policy) shift the IS curve rightward, raising both output and interest rates. However, the government wants to avoid higher interest rates because they crowd out private investment. Option C achieves both goals perfectly. The increase in government purchases directly boosts aggregate demand and output. The downward shift in the central bank's policy rule (lowering interest rates for any given output level) counteracts the upward pressure on interest rates from fiscal expansion. These policies work in tandem—fiscal policy drives output up while accommodative monetary policy keeps rates from rising. Option A fails because government purchases alone will raise interest rates along with output. Option B combines tax cuts (which increase output but also raise rates) with contractionary monetary policy (upward policy rule shift), creating conflicting effects that won't keep rates constant. Option D uses only monetary policy, which can lower rates but provides limited output stimulus compared to the fiscal-monetary combination. Remember: When facing multiple policy objectives, look for combinations where fiscal policy targets output directly while monetary policy manages the interest rate consequences. Coordinated policy is often more effective than single-tool approaches.

Question 19

The central bank's monetary policy committee becomes concerned about future inflation and decides to raise its target for the real interest rate at every level of output. In the IS-MP framework, which of the following correctly describes the adjustment to the new short-run equilibrium?

  1. The MP curve shifts up, causing a movement up and to the left along the IS curve, resulting in lower investment and consumption. (correct answer)
  2. The IS curve shifts left, as higher interest rates reduce planned investment, leading to a movement down along the MP curve.
  3. The MP curve shifts up, but the IS curve also shifts left because lower expected output reduces consumption, leading to a magnified recession.
  4. The MP curve shifts up, leading to a lower level of output, but the real interest rate returns to its original level in the new equilibrium.
Explanation: A decision to set a higher real interest rate at every level of output constitutes a contractionary monetary policy shock, which is represented by an upward shift of the MP curve. The new equilibrium occurs at the intersection of the new MP curve and the original IS curve. This corresponds to a movement up and to the left along the IS curve. The result is a higher equilibrium real interest rate and lower equilibrium output. Lower output reduces disposable income, causing consumption to fall. The higher interest rate directly causes investment to fall.

Question 20

An economy is described by the IS curve Y=3,000−100rY = 3,000 - 100r and the MP rule r=0.01Yr = 0.01Y, where Y is output and r is the real interest rate. After an increase in government spending, the new IS curve is Y=3,200−100rY = 3,200 - 100r. What is the new short-run equilibrium level of output, Y?

  1. 3,200
  2. 1,500
  3. 1,700
  4. 1,600 (correct answer)
Explanation: When you see IS-MP model questions, you're analyzing how fiscal policy affects equilibrium output and interest rates. The IS curve shows the relationship between output and interest rates in the goods market, while the MP curve represents monetary policy. To find equilibrium, you need to solve where the IS and MP curves intersect by setting them equal. With the new IS curve Y=3,200−100rY = 3,200 - 100r and the MP rule r=0.01Yr = 0.01Y, substitute the MP equation into the IS equation: Y=3,200−100(0.01Y)Y = 3,200 - 100(0.01Y) Y=3,200−YY = 3,200 - Y 2Y=3,2002Y = 3,200 Y=1,600Y = 1,600 Choice A (3,200) represents a common error where students mistake the intercept of the IS curve for equilibrium output. The intercept only shows what output would be if the interest rate were zero, which isn't realistic given the MP rule. Choice B (1,500) would result from calculation errors, possibly from incorrectly handling the algebra when combining the equations. Choice C (1,700) might come from mixing up the original and new IS curve parameters, or from arithmetic mistakes in the substitution process. Remember that equilibrium in the IS-MP model always requires solving the system simultaneously—never just read values directly from one curve. The government spending increase shifts the IS curve rightward (higher intercept), but the final equilibrium output depends on how both curves interact. Always substitute one equation into the other and solve algebraically.