Define the Consumer Prices Index
Every month, the Office for National Statistics (ONS) collects information on about 120,000 prices for a 'shopping basket' of about 650 goods and services. The alter in the prices of those items is used for calculating the rate of inflation, shown by changes in the Consumer Prices Index (CPI). The contents of the basket are reviewed each year, and changes can be made for a number of reasons. Some items enter the basket because spending on them has reached a level that demands inclusion, to make sure that the basket represents typical consumer spending. Some are contained to make data collection easier or to better coverage of particular categories.