How to study for macroeconomics: formulas, models, policy

Macroeconomics asks you to do three different things, often in the same exam question: compute a number (an unemployment rate, real GDP, a multiplier), run a model (which curve shifts, and what happens to output and prices), and trace a policy (the Fed buys bonds, then what?). Students who only memorize definitions do fine on the first quiz and badly on the midterm, because the midterm is mostly the second and third kinds.

So split your practice the same way.

Know what each part of the course asks for

The unit-by-unit map of Principles of Macroeconomics breaks the course into its stretches. In study terms:

• Units 1-5 are the shared foundations (identical to the start of micro). Supply and demand reasoning is the skill.
• Units 6-10 are measurement. Mostly formulas and definitions: GDP, growth, unemployment, inflation, trade balances.
• Units 11-13 are the models. Mostly reasoning about shifts and zones.
• Units 14-19 are policy: money, the Fed, exchange rates, budgets. Reasoning chains plus a layer of institutional facts.
• Units 20-21 are trade, shared with micro.

Build a formula sheet and work it from memory

The measurement units hold most of the arithmetic. Write each formula from a blank page, then work a fresh problem with it. These are from the course cards, recomputed:

Unemployment. 200 million adults, 112 million employed, 8 million unemployed. The labor force is 112 + 8 = 120 million. Unemployment rate = 8 / 120 = 6.7%. Labor force participation rate = 120 / 200 = 60.0%.

Real GDP. Nominal GDP is 12,000 (billion dollars) and the GDP deflator is 80. Real GDP = 12,000 / 0.80 = 15,000. With a deflator below 100 (a year before the base year), real GDP is larger than nominal.

Inflation from an index. The price index moves from 107 to 110. Inflation = (110 - 107) / 107 = 2.8%, not 3%. Subtracting index points only works when the starting index is exactly 100.

Growth and doubling. Using the rule of 70, income growing 3.5% a year doubles in about 70 / 3.5 = 20 years. It is an approximation; compound growth, start x (1 + g)^n, is the exact version.

Multipliers. Two different ones, often confused. The expenditure multiplier with no taxes or imports is 1 / (1 - MPC); with an MPC of 0.80 it is 1 / 0.20 = 5. The money multiplier is 1 / reserve ratio; with a 5% reserve ratio it is 1 / 0.05 = 20. One is about spending rounds, the other about bank lending rounds.

The method for formula sheets in how to memorize a list, a table or a formula sheet works well here: recall the whole sheet, check it, and fix only what you missed.

Practice the models as chains, not pictures

The AD/AS model is where most exam points live. The skill is running a chain: event, curve, direction, result. Write chains like these until each takes a few seconds:

• Consumer confidence falls: consumption falls, AD shifts left, real GDP falls, the price level falls, unemployment rises.
• Oil prices spike: input costs rise, short-run AS shifts left, real GDP falls and the price level rises (stagflation).
• The Fed buys bonds: bank reserves rise, interest rates fall, investment and borrowing for houses and cars rise, AD shifts right, real GDP and the price level rise.
• Congress cuts taxes in a deep recession: consumption rises, AD shifts right along the flat part of short-run AS, output rises with little change in prices.

Then add the twist exams love: where on the AS curve is the economy? The same AD shift mostly raises output far below potential GDP and mostly raises prices near it. Aggregate demand and aggregate supply explained works through shifts with a numeric schedule and the three zones.

Policy questions are the same chains with a starting point. Expansionary monetary and fiscal policy both shift AD right; contractionary policy shifts it left. The difference is who acts (the Fed versus Congress and the President) and through what channel (interest rates versus spending and taxes).

Watch the classic traps

A short list of distinctions costs students more points than anything else in the course:

The discouraged-worker case is worth working once. Start from the example above and let 2 million of the 8 million unemployed give up. Unemployed is now 6 million, the labor force 118 million, and the rate falls to 6 / 118 = 5.1%, even though nobody found a job.

The Keynesian versus neoclassical units are another contrast drill. For each school, write one line on what sets output in the short run, how fast prices adjust, and what it says policy should do. Exams ask which school a statement belongs to.

Space it across the semester

Macro is more cumulative than it looks. AD/AS in unit 11 reuses GDP components from unit 6; monetary policy in unit 15 ends in an AD shift; the government borrowing units reuse the saving and investment identity from unit 10. A final can connect any of them.

• Quiz yourself instead of rereading. The testing effect is the strongest single reason flashcards work.
• Keep old units in rotation while you learn new ones. Studying for a cumulative final vs a unit test shows how to taper review across a term.
• Plan backward from exam dates. The study schedule generator lays out the days.

A realistic week: learn the new chapter early, write its formulas and two or three chains from memory by midweek, and do 15 to 20 minutes of mixed review a day.

If you're also taking micro, accounting or government

Units 1 to 5 and the two trade units are the same in micro and macro, so review them once for both. The micro half then goes into costs and market structures instead; how to study for microeconomics covers it. The bank balance sheets in unit 14 use the same assets-equals-liabilities-plus-equity structure taught in accounting, and debits and credits explained is a quick way into it. Fiscal policy is set by Congress and the President, so the budget process in how to study for American Government fills in the political side.

Macro is one of the courses in free college gen-ed course flashcards. Encodr's free macroeconomics flashcards cover all 21 units, with every formula as a typed card and reviews on a spaced schedule.