Metropolitan Area

Metropolitan areas are large population centers (central cities) together with their adjacent zones of influence, where influence may be measured by levels of commuting to the central city or by commercial ties and media penetration—thus typically encompassing rural areas and physically separate satellite towns that are economically integrated with the core city.

Metropolitan areas were an innovation of the U.S. Census, first called “metropolitan districts” in 1930 and only fully developed as “metropolitan areas” for the 1950 Census. Areas were recognized around independent central cities of 50,000 or more people and, for most of the country, consisted of the county containing the central city plus adjacent counties with “significant” ties to the central county, in particular commuting levels of 15% or more to the central city and thresholds of density and nonagricultural employment. In New England, metropolitan areas were defined on the basis of towns, local government units smaller than the county. As these were not statistically compatible with county-based areas for the rest of the country, New England County Equivalent Metropolitan Areas were also defined. However, just as serious a problem of inconsistency and noncomparability resulted from the inconvenient fact that county size and shape varied tremendously across states.

Nevertheless, the metropolitan area designation proved immensely popular, in part because it gave competing cities some sense of their relative importance in the national economy, as well as becoming a useful measure of growth from census to census. More important, metropolitan areas soon became the legal units for implementation of myriad federal programs and for the allocation of federal funds. Indeed, the definition of areas is so politically important and sensitive that they are defined by the Office of Management and Budget in the White House and are the subject of battles for autonomy versus inclusion as part of larger areas.

Definitions and rules for delimitation have changed over the years. For example, by 1970, eligibility was based on actual urban agglomerations over 50,000 (urbanized areas), and “consolidated” metropolitan statistical areas were recognized, consisting of adjoining “primary” metropolitan areas with high levels of commuting and economic integration. As of 1990, only commuting to the core urbanized areas was used as a basis for adding outlying counties, resulting in a substantial increase in metropolitan territory and population. Periodically, taskforces have been formed to consider more basic reforms toward greater consistency and comparability, for example, defining areas based on smaller units such as zip codes or census tracts, but the availability of quality data for intercensal years only by counties [Page 1887][Page 1888]has thus far stalled such efforts. However, census tracts and zip-code-based areas (RUCAS, or rural-urban commuting areas) have been defined by the U.S. Department of Agriculture for rural-based programming.

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