CPI - Consumer Price Index

The Consumer Price Index (CPI) is a measure of the average change in prices paid by consumers for a basket of goods and services over time. It is calculated by tracking the prices of a representative sample of consumer goods and services, and averaging their price changes for a given period.

Key Points about CPI

The CPI measures the monthly change in prices paid by consumers for a fixed basket of goods and services representative of aggregate consumer spending.
It is calculated as a weighted average of prices for this basket, with weights reflecting their relative importance in consumer expenditure.
The basket of goods and services is updated periodically to reflect changes in consumer spending habits.
The CPI is one of the most widely used measures of inflation, closely monitored by policymakers, financial markets, businesses, and consumers.
It is used to adjust wages, social security benefits, tax brackets, and other payments to account for the effects of inflation.
The CPI is not a perfect measure of the cost of living, as it does not account for changes in consumer behavior or substitutions in response to price changes. However, it provides a useful estimate of inflation over time.

The CPI is typically calculated by a government institution that is separate from the Central Bank, like the National Office of Statistics.

Sources:
CPI - Inflation (takes you to an OECD website)
Consumer Price Index (takes you to Wikipedia)
Consumer Price Index (takes you to Investopedia)