primary metropolitan statistical area

primary metropolitan statistical area (PMSA)

Now obsolete but still encountered in trade literature.The term was adopted by the U.S. Census Bureau in 1990, as part of a hierarchy that started with something called a metropolitan area (MA). The MA included metropolitan statistical areas (MSA), consolidated metropolitan statistical areas, and primary metropolitan statistical areas (PMSAs).The entire hierarchy was changed in 2000,with the new concept being a core-based statistical area,which includes metropolitan statistical areas and micropolitan statistical areas.For historical reference,a PMSA consisted of two or more communities that would qualify by themselves to be an MSA (1 million or more inhabitants) but that were so closely tied together economically that they should be treated as one unit.