The consumer price index measures the monthly change in the retail prices of approximately 80,000 specific goods and services, called the market basket. The goods and services fall into eight major categories: food and beverage, housing, apparel, transportation, medical care, recreation, education and communication, and other. The Consumer Price Index is a monthly measurement of U.S. prices for most household goods and services. It reports inflation, or rising prices, and deflation, or falling prices. The Consumer Price Index (CPI) is a measure that examines the weighted average of prices of a basket of consumer goods and services, such as transportation, food, and medical care. It is calculated by taking price changes for each item in the predetermined basket of goods and averaging them.