On the Choice of Combined Statistical Areas

Some Metropolitan Statistical Areas (MSAs) fail to encompass the full extent of metropolitan areas. Combined Statistical Areas (CSAs), combinations of Core-Based Statistical Areas, are larger and may be more a more appropriate choice for certain analyses. Differences between MSAs and CSAs (and some MSAs are not even included in CSAs) range from minor to the combination of large MSAs, with population increases ranging from a few percent more than doubling. The sharing of transportation infrastructure in the form of commuter rail service and shared airports demonstrates the integration of areas combined into CSAs. In addition, the extent of the MSAs defined for the 2000 census are comparable to current CSAs, which arise from a subsequent change in how metropolitan areas are defined.