Glossary

This glossary consolidates the macroeconomic terminology used throughout How the Economy Works. Each entry provides a clear definition followed by practical context and real-world examples. Terms are arranged alphabetically for easy reference; internal cross-references use the bracketed links to guide you to related concepts throughout the book. Use this glossary as both a reference tool during reading and a quick-lookup guide once you've completed the book.

Aggregate demand

The total spending on goods and services in an economy during a specific period.

Aggregate demand includes consumer spending, business investment, government purchases, and net exports. When the Federal Reserve cuts interest rates, borrowing becomes cheaper, and households typically increase spending on homes and cars—raising aggregate demand. For example, if a 0.5% rate cut leads to $50 billion in additional home purchases and $30 billion in new business equipment, aggregate demand rises by $80 billion. Conversely, when consumers lose confidence during a recession, they postpone major purchases, and aggregate demand falls sharply.

Aggregate supply

The total quantity of goods and services that producers are willing and able to supply at various price levels.

In the short run, aggregate supply slopes upward because higher prices encourage firms to increase production in search of higher profits. Over the long run, aggregate supply is mostly determined by available labor, capital, and technology rather than price levels. When a major supply shock—such as the 2008 financial crisis or the 2020 pandemic—hits, aggregate supply can shift leftward, meaning the economy produces less at every price level. This is why stagflation (simultaneous recession and inflation) can occur when supply shocks hit alongside sustained demand.

Austerity

Government spending cuts and/or tax increases aimed at reducing budget deficits.

Austerity is often imposed during recessions or sovereign debt crises. The U.K. adopted austerity measures after 2010, cutting public spending by roughly 3% of GDP over five years to reduce its deficit. While austerity reduces government debt, it can deepen recessions in the short term by reducing demand—a trade-off known as fiscal contraction. Some economists argue austerity is counterproductive during downturns because it kills jobs and tax revenue, making deficits worse relative to output.

See also: Fiscal policy, Fiscal multiplier, Recession.

Balance of payments

A complete record of a country's economic transactions with the rest of the world, divided into the current account and capital account.

The balance of payments tracks exports and imports of goods, services, income, and financial assets. The United States has run a current account deficit for decades—meaning Americans import more than they export—while running a capital account surplus (foreigners invest heavily in U.S. stocks and real estate). A balanced payments account sums to zero; a country's surplus on one side must equal a deficit on the other. Understanding this helps explain why the U.S. dollar remains strong despite trade deficits.

Beige Book

A periodic summary of economic conditions in each of the Federal Reserve's 12 regional districts, published eight times per year.

The Beige Book synthesizes reports from business contacts, surveys, and interviews conducted by Fed staff. It paints a qualitative picture: "Manufacturing output is mixed; some regions see strength in autos, others in textiles face headwinds." While not a formal economic statistic, the Beige Book is closely watched by investors and policymakers to gauge regional economic health and inform Fed decisions. The April 2024 Beige Book, for example, noted persistent service-sector strength despite slowing manufacturing.

See also: Federal funds rate, Central bank, NBER.

Business cycle

The alternating periods of economic expansion and contraction that characterize modern economies.

A typical cycle consists of expansion (rising output, employment, and incomes), a peak (maximum output), contraction or recession (falling output and employment), and a trough (lowest point before recovery begins). The longest expansion in U.S. history ran from mid-2009 to early 2020, lasting 128 months. The 2020 recession was the sharpest but shortest on record—GDP fell 31% at an annualized rate in Q2 2020, but recovery began within weeks. Understanding the business cycle helps investors anticipate policy shifts and economic turning points.

See also: Recession, Expansion, Trough.

Capital account

The section of the balance of payments that records investment flows—purchases of stocks, bonds, real estate, and direct business investment across borders.

When a Saudi fund buys $10 billion of U.S. Treasury bonds, that transaction appears as a capital account surplus (inflow). When a U.S. private equity firm invests $2 billion to build a factory in Mexico, it appears as a capital account deficit (outflow). The U.S. capital account has been in surplus for decades, reflecting the dollar's status as the world's reserve currency and strong demand for U.S. assets. This inflow of foreign capital helps finance the U.S. current account deficit.

Central bank

The institution responsible for managing a country's money supply, setting interest rates, and regulating the banking system.

The Federal Reserve (U.S.), European Central Bank (ECB), Bank of Japan (BOJ), and Bank of England are the major central banks. They conduct monetary policy through interest-rate adjustments, quantitative easing, and reserve requirements. Central banks also act as lenders of last resort during financial crises—in 2008, the Fed lent over $1 trillion to stabilize the financial system. Their independence from political pressure is crucial for maintaining price stability and public confidence in currency.

Comparative advantage

The economic principle that specialization in production increases total output, even when one producer is more efficient at everything.

If a surgeon can both perform surgery and code software faster than a developer, the surgeon still has lower opportunity cost performing surgery (foregone software income) and should specialize there, leaving coding to the developer. Nations apply this principle: India specializes in software services (lower opportunity cost), while the U.S. specializes in advanced manufacturing. Global trade based on comparative advantage raises living standards in both countries, despite short-term disruption in non-specialized sectors.

See also: Trade deficit, Trade surplus, Net exports.

Consumer Price Index (CPI)

A monthly measure of the average price changes paid by urban consumers for a fixed basket of goods and services.

The CPI basket includes food, energy, housing, transportation, and medical care. In 2022, headline CPI (all items) spiked to 9.1%, the highest in 40 years, driven by energy and used-car prices. Core CPI (excluding volatile food and energy) peaked at 6.5%. The Fed uses CPI to gauge inflation and set monetary policy targets. If CPI rises 2% year-over-year consistently, that signals the Fed's 2% inflation target is being met; higher rates prompt rate hikes.

Consumer surplus

The difference between the price consumers are willing to pay for a good and the actual price they pay.

If you would pay $100 for a smartphone but only pay $800, your consumer surplus is $100. Aggregated across millions of buyers, consumer surplus represents the collective benefit society gains from trade. When competition increases (e.g., more phone makers), prices fall and consumer surplus rises. This is one reason why economists support free trade and oppose monopolies—they expand consumer surplus by lowering effective prices.

See also: Equilibrium price, Aggregate demand.

Crowding out

The reduction in private investment that occurs when government borrowing drives up interest rates.

When the U.S. Treasury issues $1 trillion in new bonds to finance stimulus spending, it competes with private companies for available credit. Interest rates rise as investors demand higher yields on corporate bonds to compensate. A manufacturing firm planning a $50 million factory expansion might cancel it if borrowing costs jump from 3% to 5%—the government's borrowing has "crowded out" private investment. The magnitude of crowding out depends on interest-rate sensitivity and the economy's available capital.

Current account

The section of the balance of payments that records exports and imports of goods, services, income, and transfers.

It differs from the capital account in that it measures real economic activity (goods shipped, services rendered) rather than investment flows. The U.S. current account deficit was $616 billion in 2022, meaning Americans imported $616 billion more in goods and services than they exported. This reflects strong U.S. consumer demand and the dollar's global appeal. A persistent current account deficit must be offset by a capital account surplus—foreign investors buying U.S. assets to balance the books.

Deflation

A sustained decrease in the general price level of goods and services throughout the economy.

Deflation is the opposite of inflation. During Japan's "Lost Decade" (1990s), deflation took hold as asset bubbles burst and consumer demand collapsed. Prices fell 1–2% annually, but wages and incomes fell faster, making real debt burdens heavier. Deflation is particularly damaging because it encourages people to delay spending ("prices will be lower next month"), further reducing demand. The Fed and most central banks actively target inflation of around 2% to avoid deflation's deflationary spiral.

See also: Inflation, Disinflation, Zero lower bound.

Deleveraging

The process of reducing debt levels, typically done by paying down loans or selling assets.

After the 2008 financial crisis, households and firms aggressively deleveraged. Homeowners who owed $300,000 on a $250,000 house paid down principal or walked away; corporations issued bonds to pay off bank loans. Deleveraging is economically painful in the short term—it reduces spending and slows growth—but necessary to restore balance sheets. The U.S. household debt-to-income ratio fell from 130% in 2007 to about 90% by 2015 through a combination of defaults, paydowns, and inflation.

See also: Debt, Financial crisis, Recession.

Demand-pull inflation

Inflation that arises when aggregate demand outpaces aggregate supply, causing prices to rise as "too much money chases too few goods."

During the 2021–2022 U.S. recovery, stimulus checks and low interest rates boosted demand for goods and services. Supply chains were constrained, so prices rose. Used car prices jumped 40% in 2021 as inventory ran low and demand was strong. Demand-pull inflation is different from cost-push inflation (driven by rising input costs like oil). The Fed fights demand-pull inflation by raising interest rates to cool aggregate demand.

See also: Inflation, Supply shock, Monetary policy.

Dependency ratio

The ratio of non-working-age population (under 15 and over 65) to working-age population (15–64), expressing the economic burden of dependents.

A high dependency ratio means fewer workers support each dependent through taxes and productivity. Japan's dependency ratio is about 65 dependents per 100 workers; the U.S. is about 52 per 100. As populations age (falling birth rates, rising life expectancy), dependency ratios rise, putting fiscal pressure on pensions and healthcare. This is a major long-term challenge for wealthy nations: fewer workers supporting more retirees.

Discount rate

The interest rate at which the Federal Reserve lends to commercial banks through the discount window.

It is separate from the federal funds rate (the rate banks charge each other) and is always set higher to discourage overuse. During the 2008 crisis, the Fed lowered the discount rate from 6% to 0.5%, making emergency borrowing cheap. Banks borrowed heavily, stabilizing the system. The discount rate is one of three main tools of monetary policy, alongside open market operations and reserve requirements. A lower discount rate encourages lending and supports the economy during downturns.

Disinflation

A decline in the rate of inflation, but not a decline in price levels (which would be deflation).

If inflation was 6% last year and falls to 4% this year, that's disinflation. The Fed successfully engineered disinflation in the early 1980s under Paul Volcker, raising rates to 20% and crushing inflation from 13% to 3% by 1983. Disinflation is painful—unemployment rose to 10%—but necessary to restore credibility to price stability. The key difference: in deflation, absolute prices fall; in disinflation, the rate of price increases slows.

See also: Inflation, Deflation, Monetary policy.

Dot plot

A graphical representation, released by the Federal Reserve quarterly, showing each committee member's forecast of future interest rate levels.

Each dot represents one Fed governor's or regional bank president's projected federal funds rate at the end of each year and in the longer run. Investors scrutinize the dot plot to infer future policy. If the median dot in the next chart shows rates at 5.5% (vs. today's 4.5%), markets expect future hikes. The dot plot is forward guidance: it signals the Fed's policy path without formally committing to it. Unexpected shifts in the dot plot can trigger large market moves.

Equilibrium price

The price at which the quantity of goods supplied equals the quantity demanded, clearing the market.

At $20 per bushel of wheat, farmers supply 10 million bushels and consumers demand exactly 10 million—no surplus or shortage. If price rises to $25, supply exceeds demand (surplus), so farmers cut production; if price falls to $15, demand exceeds supply (shortage), so farmers raise prices. Markets naturally gravitate toward equilibrium. In real economies, frictions and time delays mean true equilibrium is rare, but the principle explains why prices adjust to balance supply and demand.

Expansion

The phase of the business cycle during which real GDP grows, unemployment falls, and incomes rise.

Expansions can last months or years. The 2009–2020 expansion lasted 128 months, the longest on record, driven by ultra-low rates and resilient consumer demand. During expansion, corporate profits rise, stock prices typically climb, and government tax revenues increase naturally (without raising tax rates). An expansion ends when growth slows, confidence weakens, or external shocks hit—marking the onset of contraction and recession.

See also: Business cycle, Recession, GDP.

Federal funds rate

The target interest rate at which commercial banks lend reserve balances to each other overnight.

The Fed doesn't directly set this rate but targets it through open market operations (buying and selling securities). Banks must hold reserves at the Fed; overnight excess reserves are lent at the federal funds rate. The Fed's benchmark rate was 5.33–5.58% as of 2024, set during aggressive hiking to fight inflation. Lowering the federal funds rate makes borrowing cheaper across the economy; raising it restricts credit. Every 1% change in the fed funds rate typically affects mortgage rates, auto loans, and credit card rates within weeks.

Fiscal multiplier

The ratio of the change in national income to a change in government spending that caused it.

If the government spends $100 billion on infrastructure and national income rises by $150 billion, the multiplier is 1.5. A multiplier greater than 1 means the initial injection of demand is amplified as workers in construction firms spend wages, restaurants earn more, and so on. Multipliers are larger during recessions (idle resources, low opportunity cost of spending) and smaller during expansions (resources are already employed). Estimates range from 0.5 to 2.0 depending on economic conditions and methodology.

Fiscal policy

Government decisions about spending and taxation to influence the economy.

Fiscal stimulus (spending increases or tax cuts) aims to boost demand during recessions; fiscal contraction (spending cuts or tax hikes) aims to cool inflation or reduce deficits. The 2020 CARES Act—$2 trillion in spending—was massive stimulus that helped the economy recover within months but contributed to the 2021–2022 inflation surge. Fiscal policy is more political than monetary policy because Congress controls budgets, while the Fed operates with more independence. The lag between recognizing a problem and implementing fiscal policy can be long.

Forward guidance

Communication by central banks about their future monetary policy path to influence current economic behavior.

When the Fed announces, "We expect to hold rates near zero through 2023," investors adjust their expectations immediately, lowering long-term borrowing costs even before any rate change. Forward guidance is powerful because it shapes expectations of inflation, interest rates, and growth. Clear guidance reduces uncertainty and makes policy more effective. The Fed uses press conferences, statements, and the dot plot to provide forward guidance. Vague or contradictory guidance can spook markets.

GDP (Gross Domestic Product)

The total market value of all final goods and services produced within a country during a specific period, usually one year or quarter.

GDP is the broadest measure of economic output. U.S. GDP was $27.4 trillion in 2023, ranking the world's largest economy. GDP can be calculated three ways: spending ($C + I + G + NX$), income (wages + profits + interest + rent), or production (value added). GDP does not capture non-market activities (parenting, volunteering) or inequality. Real GDP adjusts for inflation, so comparisons across years reflect actual production changes, not just price increases.

See also: Expansion, Recession, Output gap.

Gini coefficient

A measure of income inequality ranging from 0 (perfect equality) to 1 (perfect inequality, one person has all income).

The U.S. Gini coefficient is approximately 0.48, meaning income is fairly unequal; Scandinavian countries cluster around 0.25–0.30 (more equal); developing nations often exceed 0.50. A rising Gini coefficient signals growing inequality. Income concentration in the top 1% has risen from 8% of total income in 1980 to 20% today in the U.S., driving higher Gini values. Policymakers debate whether inequality matters for growth and whether redistribution through taxes and transfers is necessary.

See also: Income distribution, Productivity.

Hyperinflation

Extremely rapid inflation, typically defined as monthly price increases exceeding 50% (or annual rates exceeding 12,900%).

Zimbabwe experienced hyperinflation in 2008–2009, with monthly inflation hitting 89 sextillion percent (that is not a typo); prices doubled every few days. Hyperinflation destroys confidence in currency, causing people to hoard real goods and revert to barter. Venezuela's currency collapsed starting in 2016 as hyperinflation rendered the bolivar nearly worthless. Hyperinflation is rare in developed economies with credible central banks but can emerge during wars, political collapse, or when governments print money to finance deficits with no plan to repay.

Inflation expectations

The rate at which consumers and businesses expect prices to rise in the future, influencing current wage and pricing decisions.

If workers expect 4% inflation, they demand 4% raises to maintain purchasing power; firms expect to raise prices 4%, justifying higher wage offers. If expectations become unanchored (workers expect 6%, firms expect 7%), inflation can spiral even if current inflation is moderate. The Fed actively manages expectations through communication and credibility. The Fed's target of 2% inflation is designed to anchor expectations: if everyone believes inflation will be 2%, wage and price-setting behavior aligns with that forecast, making the target self-fulfilling.

JOLTS (Job Openings and Labor Turnover Survey)

A monthly Bureau of Labor Statistics survey measuring the number of job openings, hires, and separations in the U.S. economy.

JOLTS tracks the excess of job openings over unemployed workers, a sign of labor market tightness. In 2022, job openings exceeded unemployed workers by millions, signaling a hot labor market and risk of wage-driven inflation. When job openings fall relative to unemployment, the labor market loosens and wage pressure eases. JOLTS data guides Fed decisions: tight labor markets (high openings-to-unemployment ratio) push the Fed to raise rates; loose markets (low ratio) may warrant cuts.

Keynesian economics

An economic school of thought emphasizing aggregate demand, the importance of government intervention during downturns, and the role of uncertainty in business decisions.

John Maynard Keynes argued that markets do not automatically clear (reach equilibrium) and recessions require government spending (fiscal stimulus) to restore demand. Traditional economists believed economies self-correct; Keynesians argued that process was slow and painful, justifying intervention. The 2008 financial crisis revived Keynesian thinking—massive fiscal and monetary stimulus prevented another Great Depression. Keynesians emphasize that recessions are not just temporary adjustments but can be prolonged if confidence collapses and uncertainty paralyzes private spending.

See also: Fiscal policy, Recession, Business cycle.

Labor force participation rate

The percentage of the working-age population (16+) that is either employed or actively seeking work.

The U.S. labor force participation rate has fallen from 67% in 2000 to about 63% in 2023, driven by aging (Baby Boomers retiring), declining birth rates, and increased disability claims. Lower participation means fewer workers support the economy and tax base. The rate also fell temporarily during COVID-19 as workers exited the labor force; recovery has been uneven. Understanding participation rates is crucial—unemployment can fall even if jobs shrink, if participation falls faster.

See also: Unemployment, JOLTS, Dependency ratio.

Lagging indicator

An economic statistic that changes after the overall economy has already begun to recover or decline, confirming trends after they have emerged.

Unemployment is a classic lagging indicator: companies hire weeks or months after demand recovers. Corporate profits and capital expenditures lag turning points. Lagging indicators are useful for confirming that a recession has truly ended or that recovery is solidifying, but they provide little advance warning. The Conference Board publishes monthly indexes of leading, coincident, and lagging indicators; the lagging index helps confirm the business cycle's turning points after the fact.

See also: Leading indicator, Business cycle.

Leading indicator

An economic statistic that tends to change before the overall economy begins to recover or decline, signaling future conditions.

Stock prices, new jobless claims, the yield curve, and consumer confidence are leading indicators. A sharp rise in jobless claims often precedes a recession by weeks; an upward-sloping yield curve often signals future growth. The Conference Board publishes a Composite Leading Economic Index (LEI) combining ten leading indicators. Leading indicators are valuable for forward-looking investors and policymakers, but they are imperfect—false signals occur when leading indicators move but broader trends do not follow.

See also: Lagging indicator, Yield curve.

Monetary policy

Central bank actions—adjusting interest rates, open market operations, and reserve requirements—to influence the money supply, credit conditions, and inflation.

The Federal Reserve implements monetary policy through the federal funds rate. Cutting rates encourages borrowing and spending, boosting the economy during downturns. Raising rates discourages borrowing and reduces inflation but can slow growth. Quantitative easing (buying long-term bonds when rates are near zero) is unconventional monetary policy used during crises. Unlike fiscal policy, monetary policy is set by the independent Fed, not Congress, reducing political pressure.

NAIRU (Non-Accelerating Inflation Rate of Unemployment)

The unemployment rate at which inflation is stable, neither rising nor falling.

If unemployment falls below NAIRU, tight labor markets push wages and inflation higher. If unemployment rises above NAIRU, slack allows inflation to decline. The U.S. NAIRU is estimated around 4–5%, but estimates are uncertain and change over time. In 2021–2022, many economists thought unemployment around 4% would trigger high inflation, but wage increases were smaller than expected, suggesting NAIRU had risen. Understanding NAIRU helps the Fed balance its dual mandate of stable prices and full employment.

See also: Phillips curve, Unemployment, Inflation.

NBER (National Bureau of Economic Research)

A nonpartisan research organization that officially dates U.S. business cycle turning points (recession starts and ends).

The NBER Business Cycle Dating Committee defines recessions as periods of broad decline in activity across the economy, not merely two consecutive quarters of negative GDP growth. The 2020 recession lasted just two months (official dates: February–April 2020), the shortest on record, because production and employment fell sharply but briefly. NBER dating is backward-looking and definitive; the committee often announces recession dates months after the fact. Its independence from government makes NBER dating widely accepted.

See also: Business cycle, Recession.

Net exports

The value of a country's exports minus its imports of goods and services.

If the U.S. exports $200 billion in goods and imports $300 billion, net exports are negative $100 billion (a trade deficit). Net exports are a component of GDP: $C + I + G + NX$. A trade deficit reduces GDP directly but can reflect strong domestic demand and attractive investment opportunities. U.S. net exports have been negative for decades, offset by strong consumption and investment. Countries with persistent trade surpluses (like China and Germany) may face pressure to revalue currency or increase imports.

Non-farm payrolls

A monthly measure of the number of jobs added or lost in the U.S. economy, excluding farming, released by the Bureau of Labor Statistics.

Non-farm payroll changes are eagerly anticipated on the first Friday of each month because they signal labor market health. A monthly gain of 200,000–250,000 jobs is considered robust; fewer than 100,000 is weak. The February 2023 report showed 311,000 jobs added despite banking sector turmoil, signaling economic resilience. Large monthly swings (gains of 500,000+ during recovery, losses during crisis) are normal; smoothing over three months provides a clearer trend. Fed policy often reacts to payroll surprises.

Okun's law

An empirical relationship stating that a 1% increase in the unemployment rate is associated with roughly a 2–3% decline in GDP below its potential.

Okun's law captures the cost of unemployment: jobless workers produce nothing, so output falls. If unemployment rises from 4% to 6%, GDP might fall 2–3% below its potential. The relationship holds on average but is imprecise and varies across cycles. During the sharp 2020 recession, unemployment spiked to 14%, suggesting GDP should have fallen 20–30%, but the CARES Act stimulus limited the decline to 3.4%, showing that policy can offset Okun's relationship.

See also: Output gap, Potential GDP, Unemployment.

Open market operations

The buying and selling of government securities and other assets by the Federal Reserve to influence the money supply and interest rates.

The Fed buys and sells Treasury bills, notes, and bonds to regulate the federal funds rate. Buying securities injects cash into the system (expansionary); selling drains it (contractionary). Open market operations are the Fed's primary tool, conducted daily if needed. In 2008, the Fed bought over $1 trillion in securities to prevent financial collapse. In 2022–2023, the Fed sold securities (quantitative tightening) to drain liquidity and cool inflation. Open market operations are more flexible than changing reserve requirements because they can be adjusted daily.

Output gap

The difference between actual GDP and potential GDP (the economy's maximum sustainable output), expressed as a percentage of potential GDP.

If potential GDP is $28 trillion and actual GDP is $27 trillion, the output gap is negative 3.6%, indicating unused capacity and slack labor market. A positive output gap (<3% actual above potential) signals an overheating economy likely to generate inflation. The output gap is a key input to Fed policy decisions: a negative gap justifies looser monetary policy; a positive gap justifies tightening. Estimating the output gap is challenging because potential GDP is unobservable and must be inferred from trends.

See also: Potential GDP, Okun's law, Aggregate demand.

PCE price index

The Personal Consumption Expenditures price index, a monthly measure of inflation in prices paid by consumers.

The PCE index includes more goods and services than the CPI (including imputed housing costs) and uses a different weighting. The Fed targets 2% inflation measured by PCE (core PCE excludes volatile food and energy). In 2022, PCE inflation peaked at 7.1%, well above target, prompting aggressive Fed rate hikes. The PCE index is favored by the Fed because it covers a broader consumption basket and uses chained weights that adjust as consumer preferences shift.

Phillips curve

An inverse relationship between the unemployment rate and the rate of wage/price inflation: lower unemployment is associated with higher inflation.

Named after economist A.W. Phillips, who observed this pattern in 1950s U.K. wage data. When unemployment is low, labor is scarce, wages rise, and firms pass costs on as price increases. In the 1960s, the Phillips curve guided policy; policymakers thought they could choose any point on the curve (low unemployment + higher inflation, or high unemployment + low inflation). The 1970s stagflation shattered this view: both unemployment and inflation rose together, suggesting the curve had shifted. The Phillips curve relationship still holds loosely but is flatter and less stable than once thought.

See also: NAIRU, Wage-price spiral, Inflation.

Potential GDP

The maximum sustainable level of output an economy can produce without generating accelerating inflation, based on available labor, capital, and technology.

Potential GDP is unobservable; economists estimate it from trends in hours worked, capital stock, productivity, and labor force growth. U.S. potential GDP growth is estimated around 1.5–2% annually (lower than historical 3% due to aging, slower productivity growth). When actual GDP exceeds potential (a positive output gap), inflation pressure builds; when it falls short, there is slack and disinflationary pressure. Understanding potential output is crucial for monetary policy: the Fed aims to keep the economy at potential output with stable inflation.

See also: Output gap, Productivity, Okun's law.

Producer Price Index (PPI)

A monthly measure of the average price changes received by producers for goods and services at the wholesale level.

PPI tends to lead CPI because wholesale price changes eventually pass through to consumer prices. A 10% spike in PPI for energy often precedes 2–4% inflation in gasoline prices at the pump within weeks. The Fed watches PPI closely for signals of future CPI inflation. In 2022, PPI inflation was higher than CPI for much of the year as supply-chain bottlenecks caused wholesale prices to spike before retail pass-through.

Productivity

Output per unit of input, most commonly measured as real GDP per hour of labor worked.

High productivity growth means workers produce more per hour, raising living standards and wages. U.S. productivity growth averaged 2.5% annually from 1995–2005 (the "productivity boom") but has slowed to 1.0–1.5% since 2010. Rising automation, the shift to services (which are harder to automate), and measurement challenges explain the slowdown. Productivity is the ultimate driver of long-term living-standard improvements; without it, wage growth stagnates even as nominal wages rise.

Purchasing power parity (PPP)

An exchange-rate concept suggesting that, in the long run, currencies adjust so that the same basket of goods costs the same in different countries.

If a Big Mac costs $5 in the U.S. and £4 in the U.K., PPP suggests the exchange rate should converge to $1.25 per pound (5/4). In reality, exchange rates diverge from PPP due to trade costs, capital flows, and different inflation rates. PPP is useful for comparing living standards across countries: adjusting for PPP, China's GDP per capita is higher than headline dollar comparisons suggest. The Economist's Big Mac Index tracks PPP in real time, finding the dollar often overvalued or undervalued vs. PPP predictions.

Quantitative easing (QE)

The large-scale purchase of long-term bonds and other assets by the central bank to inject liquidity and lower long-term interest rates when short-term rates are near zero.

When the Fed cut the federal funds rate to zero in 2008 and again in 2020, it resorted to QE, buying $1.7 trillion in securities by 2010 and $4.7 trillion in 2020–2021. QE works by removing long-term bonds from the market, reducing supply and lowering their yields, making borrowing cheaper. It also expands the monetary base, increasing money supply. Critics argue QE inflates asset bubbles and increases inequality (benefiting asset owners); supporters argue it was essential to prevent financial collapse and deep depression.

Recession

A period of decline in economic activity, broadly defined by the NBER as two or more consecutive quarters of negative real GDP growth.

The 2020 recession lasted two months (the shortest on record); the 2007–2009 Great Recession lasted 18 months. During recessions, unemployment rises, incomes fall, corporate profits decline, and asset prices often crash. The NBER sometimes calls a recession before two quarters of negative growth because other data (employment, industrial production) signal broad decline. Recessions are painful but necessary for restoring balance after excesses; they clear excess inventory, reset unrealistic profit expectations, and allow the economy to restructure.

See also: Business cycle, Expansion, Trough.

Recovery

The phase of the business cycle that immediately follows a recession, marked by rising output, employment, and incomes.

Recovery begins at the trough (the lowest point of recession) and ends when the economy returns to its pre-recession level of output. The 2020 recovery was the fastest on record; unemployment fell from 14.7% to 6% in six months as the economy rehired workers and demand surged. Recovery is typically stronger than expansion because idle workers and factories are brought back online (high marginal productivity). Long, sustained recoveries can eventually evolve into complacency and asset bubbles if policymakers keep stimulus in place too long.

See also: Business cycle, Trough, Expansion.

Reserve requirement

The percentage of deposits that commercial banks must hold in reserve (not lend out), set by the Federal Reserve.

The Fed can lower reserve requirements to inject liquidity (as it did in 2020, cutting the requirement to zero) or raise them to restrict credit. Lowering requirements encourages banks to lend more; raising them restricts lending. Reserve requirements are a blunt tool, rarely changed, because they affect all banks equally regardless of conditions. Open market operations and the discount rate are more frequently used. Most central banks outside the U.S. target certain money aggregates or interbank lending rates rather than reserve requirements.

Stagflation

A rare and damaging combination of stagnant economic growth (or recession) and high inflation occurring simultaneously.

The 1970s stagflation, triggered by OPEC oil embargoes and loose monetary policy, saw unemployment and inflation both exceed 9%. Traditional Phillips curve economics offered no policy escape: tightening money would reduce inflation but increase unemployment; loosening would reduce unemployment but raise inflation further. Paul Volcker's solution was to accept short-term pain (recession, 10% unemployment) to break the inflation spiral. Stagflation is the worst of both worlds for policymakers and is avoided by maintaining credible inflation expectations and supply-side flexibility.

See also: Supply shock, Phillips curve, Inflation.

Supply shock

A sudden, unexpected change in supply (positive or negative) that shifts aggregate supply and can cause stagflation.

Negative supply shocks (OPEC oil embargo, pandemic supply-chain disruptions, droughts) reduce output and raise prices. Positive supply shocks (technological breakthroughs, resource discoveries) raise output and lower prices. The 2022 energy crisis in Europe, triggered by Russia's invasion of Ukraine and supply disruptions, is a negative supply shock. Unlike demand shocks, which move output and inflation in opposite directions, supply shocks move them together, complicating policy. The Fed cannot easily offset supply shocks without accepting either higher inflation or lower output.

See also: Aggregate supply, Stagflation, Inflation.

Trade deficit

An excess of imports over exports, representing a net outflow of currency from a country.

The U.S. trade deficit in goods reached $948 billion in 2022 as Americans imported cars, electronics, and apparel faster than they exported. A trade deficit is not inherently bad—it reflects consumer demand for foreign goods and foreign investment in U.S. assets. However, persistent large deficits can signal competitiveness losses and dependence on external borrowing. The U.S. trade deficit is partly explained by the dollar's status as reserve currency and attractive U.S. investment opportunities (capital account surplus offsets trade deficit).

Trade surplus

An excess of exports over imports, representing a net inflow of currency to a country.

China, Germany, and Japan have persistent trade surpluses, exporting more than they import. China's trade surplus exceeds $400 billion annually. Trade surpluses boost GDP directly but can trigger political pressure (other countries cry "unfair competition") and lead to currency appreciation if not offset by capital outflows. Surpluses also mean a country is accumulating claims on other nations (exports are paid in foreign currency or securities). Some economists argue that persistent surpluses reflect mercantilist policies (currency manipulation, subsidies); others say they reflect savings preferences and productivity advantages.

Trough

The lowest point of a recession, where output and employment reach their minimum before recovery begins.

The trough is when the business cycle turns: it marks the end of contraction and the beginning of recovery. The 2020 recession trough was April 2020, just two months after the peak (February 2020). The 2009 recession trough was June 2009, 18 months after the peak (December 2007). Identifying the trough in real time is difficult; it is only confirmed months later when data revisions show when employment stopped falling. Investors watch for trough indicators (jobless claims, ISM Manufacturing) to anticipate recovery.

See also: Business cycle, Recession, Recovery.

Velocity of money

The rate at which money circulates through the economy, measured as the ratio of nominal GDP to the money supply.

If $1 trillion in money supply generates $5 trillion in annual economic activity, velocity is 5 (each dollar is used five times per year on average). Velocity fell sharply during the 2008 crisis and COVID-19 pandemic as people hoarded cash, reducing spending. The Fed's massive stimulus in 2020–2021 expanded money supply dramatically, but velocity rose as stimulus recipients spent the cash, generating high inflation. Understanding velocity is crucial: a given amount of money can generate different inflation depending on how fast it circulates.

Wage-price spiral

A self-reinforcing cycle where rising wages fuel price increases, which in turn fuel further wage demands, spiraling into persistent high inflation.

If workers expect 4% inflation and demand 4% raises, firms pay higher wages and raise prices to cover costs, validating the inflation forecast. Without intervention, this spiral can lead to runaway inflation. The Fed's primary task is preventing wage-price spirals by keeping inflation expectations anchored near 2%. The 1970s stagflation was partly a wage-price spiral: high inflation led workers to demand higher wages, which firms passed on as prices, perpetuating inflation. Credible forward guidance and demonstrated willingness to tolerate some unemployment to break spirals are effective preventatives.

Yield curve

A graph showing the relationship between bond maturity and yield (interest rate), typically sloping upward (longer maturities pay higher yields).

A normal upward-sloping yield curve signals economic confidence: investors accept lower yields on short-term bonds and demand higher yields on long-term bonds to compensate for duration risk. An inverted yield curve (short-term yields exceed long-term yields) is rare and historically precedes recessions. The yield curve inverted in 2022 as the Fed hiked short-term rates aggressively; many expected a 2023 recession (which did not materialize). The shape of the yield curve is a powerful leading indicator and is closely watched by the Fed and investors.

Yield curve control

A monetary policy tool where the central bank targets specific interest rates at different maturities, not just the short-term rate.

The Bank of Japan and Federal Reserve (during WWII and COVID-19) have used yield curve control to keep long-term borrowing costs down. The Fed implemented yield curve control in August 2020, purchasing bonds to pin 5-year and 10-year Treasury yields near zero, easing financial conditions. Yield curve control is controversial: it limits central bank independence, can inflate asset bubbles, and signals desperation if markets lose confidence. It is a more drastic intervention than open market operations and is typically used only in severe crises.

Zero lower bound

The constraint that central banks cannot set nominal interest rates below zero (since holding physical cash yields 0%), limiting monetary stimulus when rates are already near zero.

During severe recessions (2008, 2020), the Fed cut the federal funds rate to nearly 0%, hitting the zero lower bound and exhausting traditional rate-cutting stimulus. Further easing required unconventional tools: quantitative easing, forward guidance, and negative interest rates (attempted by some central banks with limited success). The zero lower bound is why some economists argue fiscal policy (government spending) becomes more important during severe downturns when monetary policy is exhausted. Modern economists debate whether negative rates are technically or politically feasible as an escape from the zero lower bound.

Aggregate demand​

Aggregate supply​

Austerity​

Balance of payments​

Beige Book​

Business cycle​

Capital account​

Central bank​

Comparative advantage​

Consumer Price Index (CPI)​

Consumer surplus​

Crowding out​

Current account​

Deflation​

Deleveraging​

Demand-pull inflation​

Dependency ratio​

Discount rate​

Disinflation​

Dot plot​

Equilibrium price​

Expansion​

Federal funds rate​

Fiscal multiplier​

Fiscal policy​

Forward guidance​

GDP (Gross Domestic Product)​

Gini coefficient​

Hyperinflation​

Inflation expectations​

JOLTS (Job Openings and Labor Turnover Survey)​

Keynesian economics​

Labor force participation rate​

Lagging indicator​

Leading indicator​

Monetary policy​

NAIRU (Non-Accelerating Inflation Rate of Unemployment)​

NBER (National Bureau of Economic Research)​

Net exports​

Non-farm payrolls​

Okun's law​

Open market operations​

Output gap​

PCE price index​

Phillips curve​

Potential GDP​

Producer Price Index (PPI)​

Productivity​

Purchasing power parity (PPP)​

Quantitative easing (QE)​

Recession​

Recovery​

Reserve requirement​

Stagflation​

Supply shock​

Trade deficit​

Trade surplus​

Trough​

Velocity of money​

Wage-price spiral​

Yield curve​

Yield curve control​

Zero lower bound​

End of Book 2 — How the Economy Works​