Experts dispute the validity of home-price indices commonly used in the residential housing industry and often quoted in bold headlines in the press. Recently, a headline in the San Francisco Chronicle reported a "Big drop in October home prices."
This eye-catching lead was based on data from the Standard and Poor's/Case-Shiller 10-City Composite Index that declined 19.1 percent in October 2008 from a year ago. The S&P 20-city index dropped 18 percent. The San Francisco metropolitan region index plunged a whopping 31 percent.