Which index, launched in 2000, tracks U.S. housing prices in 20 major metropolitan areas?

The S&P CoreLogic Case-Shiller Index tracks U.S. home prices across 20 major metropolitan areas in its widely cited 20-city composite.

The index grew from research by economists Karl Case and Robert Shiller, who developed repeat-sales methods to measure changes in the prices of existing single-family homes. The approach compares repeated sales of the same properties rather than simply averaging all sale prices.

The national index and metropolitan indexes are released with a reporting lag. The 20-city composite is especially familiar in financial news because it provides a broad gauge of urban housing-market movements.

The index is not a count of homes sold and does not measure every kind of property. It focuses on single-family homes and is designed to capture price changes, making it different from measures based on new-home construction, rents, or mortgage applications.