A monthly report that measures the change in prices of a group of homes in 20 major metropolitan areas in the US. The index was set to be at 100 on January 1, 2000 and tracks price changes measured as points. It includes homes that have sold before and excludes new construction, condos or homes that have been extensively remodeled. The homes in the set are similar in size and style to better determine changes in what people are willing to pay for the same home over time.
You can read more about the index's methodology at S&P Case-Shiller Index