Applying the Current Core Based Statistical Area Standards to Historical Decennial Census Data

Todd K. Gardner, U.S. Census Bureau

Since its introduction in 1950, the basic concept of a metropolitan area has remained the same: a densely settled population nucleus and the counties closely linked to that core. Alterations to metropolitan area definitions have occurred because of changes in population distribution and commuting, as well as changes in the standards used to define these areas. While researchers generally regard metropolitan area definitions from decade to decade as comparable, the specific criteria used to define these areas have changed over time. The most recent standards review, in particular, yielded standards that broke sharply with the past in some respects. This paper describes how core based statistical areas would have looked in 1960, 1970, 1980 and 1990 if the current standards were applied to data from those decennial censuses. Applying a consistent set of standards to data across time provides a more accurate picture of historical population trends for metropolitan areas.