Metropolitan Statistical Area (MSA) Codes

Before CBSA, MSA codes were used for statistical analysis by the US government

Metropolitan Area Statistical codes were developed by the US Office of Management and Budget in 1990 to assist with statistical analysis. MSA codes are arranged around county boundaries and are the formal definition of a metropolitan area. They can also be called Combined Statistical Areas. While MSA codes are still widely used, they have been replaced by CBSA codes.

MSA codes can be used for estimating the population of metropolitan area, but they are not always accurate for this purpose. Since MSA definitions change regularly, population comparisons are difficult to compare between different dates - even with the official data.