Consumer prices index

A measure of the cost of a “typical” assortment of goods and services, used to calculate the rate of inflation. Statisticians first calculate the composition of the basket of goods and services bought by the average consumer: eg, bread, petrol and electrical goods. They then compare the cost of those goods in one period with that in another, weighting the goods and services to reflect the amount the average consumer spends. The change in this consumer prices index over the period (eg, a year) is the inflation rate. For more detail, read our explainer.