Understanding Inflation: How Rising Prices Are Measured and Why They Matter

Understanding inflation — simply put

Inflation is the rate at which the general price level rises, measured as the percentage change in a price index over a year. It is not the rise in any single price but the drift of the whole price system, and how it is measured, whose spending it reflects and how central banks react to it shape almost every financial decision in an economy.

Why did inflation hit 10% after two decades near 2%?

From the euro's launch until 2021, euro-area inflation rarely strayed far from the European Central Bank's target. By October 2022 it had reached 10.6%; in the United States, consumer price inflation peaked at 9.1% in June 2022. The surge combined three forces at once: an energy shock after Russia's invasion of Ukraine (cost-push), a rebound in spending after the pandemic while supply chains were still broken (demand-pull), and the risk that both would feed into wage settlements and expectations (built-in inflation).

Whose inflation is the index measuring?

A consumer price index prices a fixed basket weighted by average household spending:

Two consequences follow. First, it is a plutocratic average: households that spend more carry more weight, so a low-income household with a large energy share faced far higher inflation in 2022 than the headline rate. Second, fixed weights ignore substitution toward goods that have become relatively cheaper, which biases measured inflation upward. A 1996 U.S. review, the Boskin Commission, estimated the total upward bias at about 1.1 percentage points a year, prompting changes to how the index is built.

Why do central banks look past the headline rate?

Energy and food prices swing with weather, wars and world markets, and those swings often reverse on their own. Central banks therefore watch core inflation, which strips them out, to judge whether price pressure has spread through the economy.

When core inflation stays high after energy prices fall, the shock has entered wages and services prices, and that is what forces central banks to act.

Why did interest rates rise so late?

What matters for spending is the real interest rate, the nominal rate minus expected inflation:

Central banks initially judged the surge temporary. The Federal Reserve began raising rates in March 2022 and the ECB in July 2022; both then tightened faster than at any time in decades. A Taylor rule summarizes how far policy "should" respond:

Why don't prices fall back when inflation does?

Disinflation is not deflation. When inflation falls from 8% to 2%, prices are still rising, only more slowly, and the price level never returns to where it was. Euro-area prices ended 2023 roughly 17% higher than in 2020. The cost of the episode is permanent unless wages catch up, which is why real wages, not the inflation rate, decide who bore it.

The takeaway

Inflation is a weighted average with built-in biases, a headline that mixes temporary and persistent forces, and a target that central banks steer through real interest rates. Read core alongside headline, compare policy rates with inflation, and remember that the price level, not the rate, is what households live with.

Further reading

• Understanding GDP — internal
• Eurostat: Harmonised Index of Consumer Prices — external reference
• European Central Bank: Monetary policy strategy — external reference