ECONM-I · Practice Final
Calibrated to look like the real final: same shape, same difficulty range, different items drawn from the bank. Work it under conditions as close to the real thing as you can: one sitting, no notes the first pass, save the reveals for after.
Multiple choice, true/false, and numerical. These reward fast, clean reasoning about a single concept.
Why:
Personal income taxes work through household disposable income. Raising them cuts after-tax income, which lowers spending growth via the velocity channel (%ΔV falls). AD shifts inward. New short-run equilibrium: lower real growth, lower inflation. This is the standard fiscal-contraction channel in the dynamic AS/AD model.
Why:
The 2008 Great Recession is the canonical modern negative AD shock. Housing-price collapse, financial-sector fragility, credit crunch, C and I fall. AD shifts left. Standard policy response: expansionary fiscal (ARRA) plus aggressive monetary easing.
Why:
A maximum price set below the market-clearing price creates excess demand at the cap. At the lower legal price, buyers want more gasoline than they did before. Sellers offer less than they did before. The gap shows up as a shortage: queues at the pump, rationing, "out of gas" signs, sales to favored customers, side-channel transactions at unofficial prices. The price ceiling did not change anyone's underlying preferences or production capacity. It changed who got the gasoline at what posted price.
Why:
Doubling time is 70 / 7 = 10 years.
Why:
When the Fed buys $50 billion in Treasuries from primary dealers, it pays for them by crediting the dealers' bank accounts with new reserves. Bank reserves in the system rise by $50 billion. With more reserves to lend, banks expand new loans, which become new deposits at other banks, which become more loans (the money multiplier). The money supply expands. This is the classic expansionary open-market operation, used by the Fed when it wants to push the federal funds rate down and stimulate borrowing.
Why:
Opportunity cost is the value of the next-best alternative Marcus gave up, not the sum of all alternatives. Ranking his options by value: catering (150, taken), freelance writing (120), brunch ($80). By taking the catering shift, he gave up the freelance writing job — the highest-value option he did not pick. His opportunity cost is 120. Adding 80 + 120 = 200 double-counts; the rule is "next-best forgone," not "everything forgone."
Why:
A recession is the classic inside-the-frontier case. The PPF itself does not move. Resources still exist, technology has not changed. They are just not being used. When the recession ends, the economy returns to the same frontier it had before.
Why:
Producer surplus = price received minus minimum willingness to accept = 30 - 18 = $12.
Why:
A binding price ceiling causes quantity supplied to fall below quantity demanded (a shortage) and destroys gains from trade that would have been made above the ceiling (deadweight loss).
Why:
Canada: 1 oil = 2 lumber and 1 lumber = 0.5 oil. Venezuela: 1 oil = 0.5 lumber and 1 lumber = 2 oil. Lower opportunity cost wins. Venezuela has CA in oil (0.5 lumber < 2 lumber). Canada has CA in lumber (0.5 oil < 2 oil).
Why:
Labor force = employed + unemployed = 143 + 7 = 150 million. Unemployment rate = 7/150 × 100 = 4.667, rounded to 4.7 percent.
Why:
Rule of 70: doubling time is about 70 / growth rate. 70 / 3 is about 23.3 years. Accept 23 or 24.
Two-to-three-paragraph responses. Each item asks you to identify a framework, apply it, and name a limitation or complication. Show your work on any quantitative item.
Sample answer:
A pessimistic public statement lowers consumer and business confidence. Households expect harder times and cut spending; firms expect lower future revenue and postpone investment. Both effects lower the velocity of money (%ΔV falls). By the identity %ΔM + %ΔV = π + Yr, spending growth falls. AD shifts inward. The new short-run equilibrium has lower real growth and lower inflation. Unemployment rises. The recession the president warned about has happened in part because of the warning. This is the demand-driven (Keynesian) story: nominal spending decisions in the present can drive the real economy's growth rate in the short run because of sticky wages and money illusion. The classical (Say's law) view holds that supply creates its own demand and that real output is determined by the economy's real productive capacity (LRAS), not by spending decisions. In the classical world, a confidence drop that lowered AD would only lower the price level (or inflation), not real output: the economy would still grow at its potential rate. The dynamic AS/AD model splits the difference. In the long run, LRAS dominates: the economy grows at its potential growth rate regardless of demand. In the short run, sticky wages and money illusion mean that AD shifts can move real growth, so the Keynesian story is right for the time horizon over which contracts are sticky. Both views are present in the same diagram, on different time horizons.
Key points an answer must hit:
Grading notes:
3 pts for the mechanism walk-through (1 pt confidence to spending, 1 pt to AD-left, 1 pt to equilibrium effect). 1 pt for noting the asymmetric effect when starting in flat SRAS. 2 pts for correctly identifying as Keynesian and contrasting with Say's law.
Sample answer:
Contractionary monetary policy raises interest rates, which reduces interest-sensitive consumption (durables, housing) and investment. Aggregate demand shifts left. Because the AD impulse from 2020-21 stimulus was a major contributor to the inflation, reversing that impulse is a direct way to push the price level back down. The tradeoff: shifting AD left also reduces real output and raises unemployment in the short run. If the SRAS curve is steep at current output levels (close to potential), most of the AD pullback shows up as lower prices and only modestly lower output, a relatively painless disinflation. If SRAS is flat (lots of slack), the same pullback would cost more output for less inflation reduction. The Fed's bet in 2022 was that the labor market was tight enough that AD compression would mostly hit prices, not jobs.
Key points an answer must hit:
Grading notes:
1 pt for the mechanism (rates up, C and I down, AD left); 1 pt for the diagnostic link to the AD source of inflation; 2 pts for the output/unemployment tradeoff; 2 pts for the SRAS-slope conditional; 1 pt for naming the Fed working assumption.
Sample answer:
The chip shortage changed an input the auto industry depends on, not the price of cars themselves. Sellers (auto manufacturers) are the side affected: at every price they can offer, they can produce fewer cars. The supply schedule moves leftward at every price. With demand unchanged and supply lower, the new equilibrium has both a higher price and a lower quantity than before. Dealerships sell fewer new cars, and the cars they do sell go for more. This matches what happened in 2021 and 2022: new-car prices rose sharply, used-car prices rose with them, and inventories stayed thin. The four-step move says: what changed (input availability), who is affected (supply side), in which direction (less at every price), and what happens to the equilibrium (higher P, lower Q).
Key points an answer must hit:
Sample answer:
The $2 million in launch and gate-leasing fees is sunk. It is already paid and cannot be recovered whether the route continues or stops. The marginal rule says: compare marginal revenue and marginal cost of the next flight, not the historical cost of starting the route. The marginal revenue of one more flight is 18,000. The marginal cost is 15,000. 18,000 minus 15,000 is $3,000 of marginal profit per flight, so each additional flight adds to the airline's total profit. The executive is committing the sunk cost fallacy: treating the 2 million as if it were a cost of the next flight. Cancelling the route does not recover any of the 2 million; it forfeits the $3,000 per flight of marginal profit. The airline should keep flying the route while marginal revenue exceeds marginal cost.
Key points an answer must hit:
Sample answer:
Buyers bear most of the burden because they cannot walk away. Nicotine addiction means a higher posted price does not move many cigarette smokers off cigarettes. They keep buying, paying nearly the full tax in the price. Sellers, by contrast, face active competition from other tobacco firms and can shift product lines. They can walk away from the cigarette market more easily than buyers can walk away from cigarettes, so the tax wedge falls more heavily on the inelastic side: the buyers. The tax will raise meaningful revenue. Quantity demanded falls only modestly (because buyers cannot easily quit), so the tax base stays large. A 1 per pack tax on a market that sells nearly the same quantity at the new price collects close to 1 per pack times the new (only modestly lower) quantity. This is the case for using cigarette taxes as a revenue tool: the addiction that makes the policy regressive from a welfare standpoint also makes it predictable from a revenue standpoint.
Key points an answer must hit:
Grading notes:
2 pts: correct identification (buyers bear burden). 2 pts: explanation via who-can-walk-away. 1 pt: prediction that revenue is meaningful. 1 pt: explanation that quantity falls only modestly.
Roughly 400-word responses to a multi-part scenario integrating two or three ideas across units.
Sample answer:
The 2008-09 response is a clear case of fiscal and monetary policy pulling together. Congress passed ARRA: roughly $830 billion of tax cuts, transfers, and direct spending, all aimed at pushing AD right. At the same time, the Federal Reserve cut the federal funds rate to near zero and began large-scale asset purchases (quantitative easing), also aimed at pushing AD right through the interest-rate and asset-price channels. Both tools, same direction. The combined effect was a larger rightward AD shift than either could have produced alone, and the response was matched to the diagnosis (an AD-collapse recession in the flat region of SRAS). The early-1980s case is the canonical example of monetary offset. Reagan-era fiscal policy ran large deficits through tax cuts and defense spending, which on its own would have pushed AD right. Paul Volcker's Fed was simultaneously running the tightest monetary policy in modern U.S. history, raising the federal funds rate above 19 percent at one point to crush inflation expectations that had become un-anchored in the 1970s. Monetary contraction reversed a large part of the fiscal AD push. The net effect on AD was much smaller than the fiscal expansion alone would suggest. The deficits drove real interest rates very high, crowded out interest-sensitive investment, and contributed to the early-1980s recession that finally broke inflation. In the AS/AD framework, coordination matters because both fiscal and monetary policy act primarily on the AD curve. When they push together, the AD shift is the sum (roughly) of the two pushes. When they push apart, much of one cancels the other, and the policy mix mostly affects the composition of demand (more government, less interest-sensitive private investment) rather than its total. Genuine coordination is difficult in the U.S. system by design. The Federal Reserve is independent: the president appoints governors to 14-year terms and the Federal Reserve Act insulates the Board from direct political instruction. The reason for that independence is historical and important. A Fed that takes orders from Congress is a Fed that monetizes debt when convenient, which produces the kind of inflation-expectation un-anchoring that the 1970s demonstrated. The cost of independence is that fiscal and monetary policy are pursued by two institutions answering to different mandates and different time horizons. Coordination happens through communication and shared analytical frameworks, not through a single decision-maker, and during disagreements the result is the kind of offset the early 1980s showed.
Key points an answer must hit:
Grading notes:
Out of 15 pts: 3 pts for the coordinated example with mechanism; 3 pts for the monetary-offset example with mechanism; 3 pts for the AS/AD framing of why coordination matters; 3 pts for the structural reason (Fed independence); 3 pts for clarity and synthesis.
Sample answer:
(1) The 2021-23 inflation was both a demand-side and a supply-side story, with the demand side more empirically important than many supply-only accounts admitted. Demand-side evidence: $5 trillion in cumulative fiscal support during 2020-21 directly raised household nominal spending power; pent-up savings unwound rapidly as the economy reopened; headline unemployment fell below 4 percent (a tight labor market is incompatible with a demand shortfall). Supply-side evidence: shipping backlogs and semiconductor shortages constrained aggregate supply through 2021-22; labor-force participation remained depressed; energy prices spiked in early 2022 (Russia's invasion of Ukraine). The clean AS/AD diagnosis is a rightward AD shift into a constrained SRAS: demand surged into a supply curve that could not fully respond, producing price increases much larger than the corresponding quantity increases. This is the mirror image of 2008-09, where AD collapsed against a relatively undamaged SRAS. (2) The Fed's tightening transmits through (a) the federal funds rate rises, raising the cost of overnight bank borrowing; (b) banks pass higher rates through to consumer and business loans (mortgages, credit cards, business credit lines, corporate bonds); (c) higher borrowing costs reduce interest-sensitive spending — housing demand falls first, business capex follows, durable consumer goods slow; (d) the slowdown in spending shifts AD leftward, easing the demand-side pressure on prices. The lag (typically 12 to 18 months from rate move to inflation response) exists because households and firms revise contracts, leases, and capital plans on their own timetable; price setters do not instantly respond to a single Fed meeting. This is why the Fed started raising rates in early 2022 and inflation did not peak until mid-2022 — the rate hikes did not move prices instantly, they pulled forward decisions across the economy. (3) The 'purely supply-driven' critique has a partial point but ultimately fails. It is correct that supply shocks (shipping, oil, labor) contributed real upward pressure on prices, and that a Fed that tried to fully crush a supply-shock-driven inflation would have to engineer a deep recession to do so. But the critique fails on the diagnostic side: the simultaneous evidence of a very tight labor market, large fiscal support, and a price level rising across a broad range of goods (not just shipping- or energy-dependent ones) is the signature of an AD-side component. The outcome confirms the diagnosis: the Fed tightened and inflation came down without unemployment spiking — exactly what the AS/AD model predicts when AD is moved leftward from an over-stimulated starting point into a still-improving supply environment. Had the inflation been purely supply, the tightening would have had to break the labor market to break the inflation; that did not happen. (4) The two episodes called for opposite policy postures because they were opposite AS/AD shocks. 2008-09 was a collapse in aggregate demand into a relatively healthy supply side — the right response was to push AD back to the right (loose money, large fiscal). 2021-23 was the reverse — excessive AD pushed into a constrained SRAS, with the right response being to ease AD back to the left (tight money) while letting the supply side heal. The same model (AS/AD), the same toolkit (monetary + fiscal), opposite shocks, opposite policy. The honest lesson is that macro policy is not 'loose is always good' or 'tight is always good' — the right move depends on the diagnosis.
Key points an answer must hit:
Grading notes:
Most-missed point in part 1: students often pick one side ('it was supply, period' or 'it was fiscal stimulus, period') instead of articulating the joint story. Full credit requires explicit recognition that both contributed. Most-missed in part 3: students may simply restate the critique without evaluating it against the observed outcome — full credit requires using the inflation-fell-without-unemployment-spike fact to test the critique. Part 4 is the synthesis: a student who answers correctly should be able to articulate the AS/AD framework as a diagnostic tool, not as a recipe.
Sample answer:
Four-step move: in an emergency such as a major transit shutdown, what changed is rider circumstances. Buses are not running, so riders who would have taken the bus now want a rideshare ride instead. The price of rideshare itself did not change first; rider circumstances did. Who is affected: buyers. Direction: at every fare, more riders want a ride than before. With supply (drivers logged on) roughly fixed in the very short run, the new equilibrium has a higher price. Surge pricing then signals drivers to log on, and the quantity of rides supplied rises as well. Prices as signals: the surge price tells riders to economize. A rider who could walk twenty minutes, share a ride with a friend, or wait an hour will think twice when she sees a 3x multiplier. The same surge price tells drivers that a ride right now is unusually valuable, and is worth coming in from across town or interrupting an evening to provide. As Hayek's tin example in the marquee suggests, neither party needs to know the underlying cause of the emergency. The price alone carries the information. Banning surge pricing during emergencies: holding the fare at its normal level prevents the price from doing this signaling work. The number of rides provided would almost certainly be lower than under surge pricing, because drivers would have less reason to log on during a difficult period. The available rides would be rationed by waiting time and luck rather than by willingness to pay. Some riders who valued the ride very highly (a parent picking up a sick child, a worker who absolutely had to get home) would not get one, while others who happened to open the app at the right moment and were content to wait would. Many riders would be worse off, even though those who got a ride paid less. The visible cost (the surge price) is replaced by an invisible one (long waits, unmet rides, lottery-style distribution).
Key points an answer must hit:
Grading notes:
Four-step move applied correctly: 4 pts. Prices-as-signals explanation (Hayek): 4 pts. Counterfactual reasoning about the ban (rationing-by-waiting, fewer drivers, worse distribution): 5 pts. Quality of writing and a clear stated position: 2 pts. Total: 15 pts.
Sample answer:
A PPF shows the maximum combinations of two goods an economy can produce given its resources, technology, and institutions. When Alpha's frontier ends up four times the size of Beta's after six decades of identical starting conditions, the explanation has to be something that shifts the frontier outward, not something that moves an economy around inside it. The three standard categories of cause that shift a PPF outward over time are: more resources, better technology, and better institutions. More resources includes physical capital accumulation (machines, buildings, infrastructure) and human capital (schooling, training, health). Concrete example: Korea's investment rate ran above 30 percent of GDP for decades and its school-enrollment rates approached universal secondary by the 1980s. Better technology means new ways of combining inputs to produce more output (semiconductors, container shipping, mRNA vaccines). Concrete example: the diffusion of computer technology raised manufacturing productivity across the OECD in the 1990s. Better institutions means the rules of the game: property rights, enforceable contracts, rule of law, low corruption, predictable politics. Concrete example: post-1990 Chile preserved private property and judicial independence while neighboring Venezuela did not, and the growth paths diverged accordingly. A recession is not a candidate explanation because a recession is a temporary movement inside the PPF, not a smaller PPF. When unemployment rises and factories run below capacity, an economy is producing below what its frontier allows; the frontier itself has not moved. Even a deep recession lasts a handful of years, while the Alpha-Beta gap accumulated over sixty. A multi-decade four-fold productive capacity gap requires the frontier itself to have moved, not just the operating point inside it. One ceteris paribus assumption: the PPF holds population size constant across the comparison. Naming this matters because the meaning of 'four times the size' changes depending on what is fixed. If Alpha's population is four times Beta's, the per-capita gap disappears. If populations are similar, the per-capita gap is real and large. The PPF picture is silent on which case applies, so the reader has to label the assumption to know whether the comparison is about country-level output or living standards.
Key points an answer must hit:
Grading notes:
4 pts for the three causes (1 pt each for naming, 1 pt for at least two concrete examples); 5 pts for the recession analysis (3 pts for the inside-vs-shift distinction, 2 pts for explaining why recession does not fit a 60-year gap); 4 pts for the ceteris paribus section (2 pts for naming an assumption, 2 pts for explaining why naming it matters); 2 pts for writing quality and staying within word count.