Consumer price index
In economics, the Consumer Price Index (CPI) is a statistical measure of a weighted average of prices of a specified set of goods and services purchased by wage earners in urban areas.A Consumer Price Indexes (CPI) or Retail price index is a price index which tracks the prices of a specified set of consumer goods and services, providing a measure of inflation.
The CPI is a fixed quantity price index and cannot reflect the improvement/deterioration of quality. The CPI also ignores the introduction of new products.
In the U.S. CPI figures are prepared monthly by the Bureau of Labor Statistics of the United States Department of Labor.