Measuring Migration: Profiling Residential Mobility across Two Decades

Abstract

The demography of a local population is a central aspect of applied social science research. Although birth and death rates influence a population, the key contributing factor influencing the demographics of a locality is almost always internal migration—the movement of persons between U.S. regions, states, and localities. Current definitions of internal migration used by the U.S. Census Bureau are limited because confidentiality restrictions require that detailed current and former place of residence geographic information be suppressed in publicly available files. In this paper we report the results of our work with confidential versions of the 1990 and 2000 decennial census microdata to develop an improved measurement of migration in order to develop a profile of internal migration in the United States. We perform our analysis for two contrasting time periods, 1985–1990 and 1995–2000. Our interest here is to assess the stability of the profile of migrants during a time period of economic contraction and expansion. Using confidential internal versions of the 1990 and 2000 Census long-form microdata, we estimate logistic models of the likelihood that individuals will migrate. The geographic detail in the internal Census data permits us to measure migration in ways that are not possible with public-domain Census data on persons. We develop migration definitions that distinguish between local residential mobility likely associated with life course transitions from migration out of the labor market area that may be driven more by employment and other socioeconomic considerations. Using logistic modeling, we find that the same individual attributes predict migration reasonably well during both periods. We also compute some illustrative probabilities of migration that show temporal stability in migration predictors could be lessened by certain changes in population composition.