Inflation is one of the most closely watched economic indicators, influencing everything from grocery bills to Federal Reserve policy. Here's a grounded explanation of what it measures and why it matters.

What inflation actually measures

Inflation refers to the rate at which the general price level for goods and services rises over time, which in turn reduces the purchasing power of a given amount of money. A modest, stable inflation rate is generally considered normal in a healthy economy; the concern arises when inflation accelerates faster than wages and incomes can keep pace with.

How inflation is measured

In the United States, the most widely cited inflation measure is the Consumer Price Index (CPI), published monthly by the Bureau of Labor Statistics. The CPI tracks the average change in prices paid by consumers for a fixed basket of goods and services, covering categories like housing, food, transportation, and medical care. The Federal Reserve also closely watches a separate measure, the Personal Consumption Expenditures (PCE) price index, published by the Bureau of Economic Analysis, which uses a different methodology and is the Fed's preferred inflation gauge.

  • Headline inflation includes all items in the basket, including volatile categories like food and energy.
  • Core inflation excludes food and energy prices, which tend to be more volatile, to highlight underlying price trends.

What causes inflation

Economists generally point to several overlapping drivers of inflation:

  • Demand-pull inflation, when demand for goods and services outpaces the economy's ability to supply them.
  • Cost-push inflation, when rising costs for inputs like labor, energy, or materials push businesses to raise prices.
  • Monetary factors, including the overall growth of the money supply and interest rate policy.
  • Supply shocks, such as disruptions to global supply chains or commodity markets, which can push prices up independent of domestic demand.

How the Fed responds to inflation

The Federal Reserve's dual mandate includes pursuing stable prices, which is why the Fed often raises its target interest rate when inflation runs persistently above its stated goal. Higher rates are intended to cool demand by making borrowing more expensive, which can help slow price increases over time, though the effects typically take months to show up in the data.

Why inflation matters to households

Persistent inflation erodes the purchasing power of savings held in cash and can outpace wage growth if incomes don't rise at a similar rate. It also affects interest rates on loans and savings accounts, since lenders and savers generally adjust the rates they're willing to offer or accept based on expected future inflation.

Deflation: the opposite problem

While high inflation draws more public attention, falling prices -- deflation -- can also create economic problems, including delayed consumer spending as buyers wait for lower prices, and increased difficulty for borrowers repaying debts, since deflation effectively increases the real value of existing debt.

How inflation expectations shape behavior

Economists pay close attention not just to current inflation but to inflation expectations -- what businesses, workers, and investors believe future inflation will be. If people expect higher inflation, they may push for larger wage increases or raise prices preemptively, which can itself contribute to further inflation, a dynamic sometimes called a wage-price spiral. Because of this, central banks like the Federal Reserve place significant weight on keeping inflation expectations "anchored" near their target, viewing credibility as an important tool for managing inflation over time.

Historical U.S. inflation episodes

The United States has experienced markedly different inflation environments across its history. The late 1970s and early 1980s saw a period of persistently high inflation, which the Federal Reserve under Chairman Paul Volcker addressed through a sustained period of sharply higher interest rates, at the cost of a significant recession. In contrast, the decade following the 2008 financial crisis was generally characterized by unusually low inflation, prompting different policy debates about how to stimulate demand.