Micropolitan areas and the measurement of American urbanization

With the official designation of micropolitan areas in June 2003, as part of the new core-based statistical area system, non-metropolitan territory is no longer an undifferentiated residual. In this paper we compare the demographic and socioeconomic characteristics of a preliminary set of micropolitan areas with more highly urbanized territory and with territory outside core-based statistical areas, to answer questions about the micropolitan category's conceptual validity. Demographic and economic data are used, along with a mail survey of county officials in a random sample of small metropolitan, micropolitan, and non-core-based statistical areas (non-CBSAs). The analysis shows substantial differentiation between micropolitan and non-CBSA areas, and demonstrates the importance of distinguishing between these two types of non-metropolitan areas. As an intermediate category, micropolitan areas provide stability to the decade-to-decade swings in non-metropolitan population change during periods of higher out-migration, but share almost equally with non-CBSA areas in attracting migrants during periods of high non-metropolitan in-migration. In terms of services available and their function as urban centers, micropolitan areas are intermediate between small metropolitan and non-CBSA areas, but more similar to small metropolitan areas.