Inflation

Inflation is measured by comparing the cost of a defined basket with its cost in an earlier period. The Consumer Price Index estimates changes in prices paid by urban consumers, while the Personal Consumption Expenditures price index captures a broader set of expenditures and allows spending patterns to change.¹

The headline rate includes volatile categories such as food and energy; core inflation excludes those categories to clarify underlying trends, although it is not a complete measure of household experience. A price level can rise more slowly while remaining high: disinflation means a decline in the inflation rate, whereas deflation means a sustained decline in the general price level.

Index construction involves sampling, weighting, quality adjustments, and treatment of new products. Consequently, an index is a statistical estimate of average price change rather than a personal cost-of-living calculation.

Inflation can arise when aggregate demand grows faster than an economy’s capacity to supply goods and services, when production costs or imported prices increase, or when expectations and wage-price decisions reinforce one another. Demand pressures may follow strong household spending, fiscal expansion, or accommodative monetary conditions; supply pressures can follow energy shocks, shortages, disasters, or disruptions in trade.

These categories overlap. A supply shock can initially raise prices while reducing output, and later inflation may persist if firms, workers, and consumers revise expectations. Economists therefore examine labor-market conditions, productivity, unit labor costs, exchange rates, credit conditions, and measures of expected inflation rather than attributing every episode to a single cause.²

Historically, severe episodes have sometimes reflected fiscal and monetary accommodation alongside constraints on production. The 1970s inflation in advanced economies, for example, combined policy, wage, and energy-market forces rather than having one simple origin.³

Inflation redistributes purchasing power between borrowers and lenders, people whose incomes adjust quickly and those whose incomes are fixed, and holders of cash and nominal bonds. Unexpected inflation can reduce the real burden of fixed-rate debt, while predictable inflation can be incorporated into contracts, wages, and interest rates. Persistent inflation also complicates saving, investment, accounting, and economic planning.

Central banks generally respond by changing policy interest rates and financial conditions, seeking to bring demand and inflation expectations into better balance. The Federal Reserve describes a 2 percent inflation rate over the longer run, measured by the annual change in the PCE price index. Governments may also alter taxes, spending, transfers, competition rules, or temporary support for affected households, but broad price controls can create shortages and distort incentives when maintained for long periods.

The distributional effect depends on household spending patterns: lower-income households often devote larger shares of their budgets to necessities, making food, housing, and energy inflation especially consequential.

Inflation is not uniform across places, products, or people. Regional indexes, owner-equivalent rent measures, and different household baskets can produce substantially different experiences from the national headline figure. New goods and improvements in quality also create measurement problems: a higher price may partly reflect a better product, while a product that disappears can be difficult to compare with its replacement.

Some economies have experienced hyperinflation, conventionally associated with extremely rapid price increases that destroy money’s usefulness as a unit of account and medium of exchange. At the other extreme, modest positive inflation can give monetary policy room to reduce real interest rates and can help wages adjust without requiring widespread nominal wage cuts.⁴

Inflation indexing links pensions, tax thresholds, wages, or government bonds to a price measure. Such clauses protect purchasing power in some contracts but can also transmit past inflation into future payments, depending on their design.

Consumer Price Index

A statistical index measuring average changes in prices paid by consumers for a selected basket of goods and services.

Core inflation

A measure that commonly excludes food and energy prices to reduce the influence of short-term volatility.

Disinflation

A decrease in the rate of inflation, without necessarily producing falling prices.

Deflation

A sustained decline in the general price level.

Hyperinflation

An exceptionally rapid and destructive acceleration of prices that undermines the functions of money.