The Survey of Construction (SOC) is conducted by the Manufacturing and Construction division of the U.S. Census Bureau with partial funding from the Department of Housing and Urban Development (HUD). Since construction and housing starts naturally occur before completion, surveys such as the SOC can indicate changing trends before they fully manifest in the housing market. For example, according to Dr. Paul Emrath, a writer on Economics and Housing Policy for the National Association of Home Builders (NAHB), the trend that manifested during the recent housing downturn of median sized single family homes could be seen a whole year previous in the SOC before it manifested to the rest of the market.
Read the full article here: Interesting Facts from the Housing Recovery