Macroeconomics, explained

What is macroeconomics?

Microeconomics studies individual markets — the price of coffee, one company’s hiring, a family’s budget. Macroeconomics zooms out to the whole economy: total output, overall prices, the unemployment rate, interest rates and how governments and central banks try to keep things steady.

Macroeconomists ask three big questions: Why do economies grow over time? Why do they sometimes shrink (recessions)? And why do prices rise (inflation)?

GDP: measuring the economy

Gross Domestic Product (GDP) is the total value of all final goods and services produced in a country in a year. U.S. GDP is roughly $30 trillion. It can be added up by spending:

Real GDP adjusts for inflation, so it measures how much stuff is produced, not just how many dollars change hands. When people say “the economy grew 2.5%,” they mean real GDP.

▶ Raise G and watch GDP

The business cycle

Economies don’t grow in a straight line. They move through a business cycle:

• Expansion — output and jobs grow. Most of the time the economy is here.
• Peak — growth tops out; sometimes the economy “overheats” and inflation rises.
• Recession — a significant, widespread decline in activity lasting more than a few months. A common rule of thumb is two quarters in a row of falling real GDP, but the official U.S. referee, the National Bureau of Economic Research (NBER), looks at jobs, income, spending and production too.
• Trough — the bottom, after which recovery begins.

A depression is a very severe, long recession — like the 1930s, when unemployment hit about 25%. Stagflation is the painful combination of stagnant growth and high inflation, as in the 1970s.

▶ Trigger a recession Replay real recessions

Unemployment

The unemployment rate is the share of the labor force — people working or actively looking for work — who don’t have a job. Economists describe three types:

• Frictional: people between jobs or just entering the workforce.
• Structural: workers whose skills or location don’t match available jobs (e.g., after a factory closes).
• Cyclical: job losses caused by recessions. This is the type policy tries to fight.

Frictional + structural unemployment make up the natural rate of unemployment, around 4–4.5% in the U.S. Okun’s law links jobs to output: when output falls about 2% below its potential, unemployment rises about 1 point.

Inflation & deflation

Inflation is a general rise in prices, usually measured by the Consumer Price Index (CPI). The Federal Reserve aims for about 2% a year. Inflation can come from:

• Demand-pull: too much spending chasing too few goods (an overheated economy, too much money).
• Cost-push: higher production costs, such as an oil price spike.
• Expectations: if everyone expects 5% inflation, workers ask for 5% raises and firms raise prices 5% — so it happens.

Deflation — falling prices — sounds nice but can be dangerous: people delay purchases and debts become heavier in real terms. Hyperinflation happens when governments print money to pay their bills: Germany (1923), Zimbabwe (2008), Venezuela (2018).

▶ Print money and watch prices

Aggregate demand & aggregate supply

The AD–AS model is supply and demand for the whole economy. The vertical axis is the overall price level; the horizontal axis is real GDP.

• Aggregate demand (AD) slopes down. It shifts right when C, I, G or NX rise — tax cuts, lower interest rates, more confidence, more government spending, stronger exports.
• Short-run aggregate supply (SRAS) slopes up. It shifts left when production costs rise — oil shocks, disasters, tariffs on inputs.
• Long-run aggregate supply (LRAS) is vertical at potential GDP. It shifts right with more workers, more capital and better technology.

A right shift of AD raises output and prices. A left shift of SRAS raises prices but lowers output — stagflation. The simulator draws this diagram live under the main chart.

▶ Shift SRAS with an oil shock

Monetary policy & the Federal Reserve

The Federal Reserve (“the Fed”) is America’s central bank. Congress gave it a dual mandate: maximum employment and stable prices. Its main tools:

• The federal funds rate — the Fed sets a target for the overnight rate banks charge each other. It moves all other interest rates.
• Open market operations & quantitative easing (QE) — buying or selling government bonds to add or remove money and push long-term rates down or up.
• Interest on reserves and the discount rate — the rates the Fed pays banks and lends to them.

Expansionary (“easy”) policy cuts rates to fight recessions. Contractionary (“tight”) policy raises rates to fight inflation. Policy works with a lag of about 1–2 years. The Taylor rule is a famous formula for where rates “should” be: raise them when inflation is above target or the economy runs hot.

▶ Raise interest rates ▶ Let the Fed respond automatically

Interest rates & bonds

An interest rate is the price of borrowing money. Long-term rates, like the 10-year Treasury yield, depend on where markets expect short-term rates to go, on expected inflation, and on risk. Mortgage rates follow the 10-year yield.

Bond prices and yields move in opposite directions: when rates rise, existing bonds paying lower rates become less valuable. Higher rates also tend to lower stock prices, because future profits are worth less today.

Fiscal policy, deficits & debt

Fiscal policy is government spending and taxation, set by Congress and the President. Expansionary fiscal policy (more spending, lower taxes) boosts AD; contractionary policy does the opposite.

• Multiplier effect: $1 of government spending becomes someone’s income, which they partly spend, and so on — so GDP can rise by more than $1.
• Crowding out: heavy government borrowing can push up interest rates and reduce private investment.
• Automatic stabilizers: tax revenue falls and unemployment benefits rise in recessions automatically, cushioning the fall.

The deficit is one year’s shortfall (spending − revenue). The national debt is the total accumulated borrowing. When interest rates exceed the economy’s growth rate, debt tends to grow faster relative to GDP.

▶ Cut taxes

The Phillips curve & expectations

In the short run there is often a trade-off: lower unemployment comes with higher inflation (the Phillips curve). But in the 1970s, economists Milton Friedman and Edmund Phelps showed the trade-off disappears in the long run once people expect higher inflation. That’s why central banks care so much about keeping inflation expectations “anchored.”

Supply shocks

Some events hit the economy’s ability to produce: oil embargoes, pandemics, wars, droughts, supply-chain breakdowns. A negative supply shock raises prices and lowers output, leaving policymakers with no good option — fighting inflation deepens the slump, and fighting the slump worsens inflation.

▶ Hit the economy with a pandemic

Housing & credit

Housing is the largest asset most families own, and mortgage lending is a huge part of the financial system. Home prices rise with incomes, population and easy credit, and fall when mortgage rates rise. Credit-fueled bubbles can be dangerous: the 2006–2008 housing crash triggered the worst financial crisis since the Great Depression.

▶ Open the Housing Lab

Trade & the global economy

Countries gain from trade by specializing in what they produce relatively well (comparative advantage). Tariffs — taxes on imports — protect some industries but raise prices for consumers and often invite retaliation. When the world economy slows, demand for a country’s exports falls too.

▶ Start a trade war

Long-run growth

Over decades, what matters most is productivity — how much each worker can produce. It grows with education, technology, better machines and good institutions. Growth of about 2% a year doubles living standards roughly every 35 years. Monetary and fiscal policy smooth the business cycle; productivity determines the long-run trend.

▶ Boost productivity