Definition of Index (economics)

This article is about index in an economics and finance sense. For other uses, see Index.

In economics and finance, an index is a single number calculated from an array of prices or of quantities. Examples are a price index, a quantity index (such as real GDP), a market performance Index (such as a labour market index / job Index or a stock market index). Values of the index in successive periods (days, years, etc.) summarize level of the activity over time or across economic units (regions, countries, etc.).