Changes In The Demographic Determinants Of U.S. Population Mobility: 1940-80

As a rule of thumb. about one-fifth of all Americans change residence in a given year, and over the course of five years, about half of all persons change residence. While this generalization has remained roughly true over the last few decades, there have been appreciable shifts in the relative distribution among types of moves. Taking an integrated approach. we examine the choice to move locally, to migrate within a state, or to migrate between states over the period 1940-80. Using a multinomial logit model and U.S. census microdata, we test for the presence of changes in the determinants of residential mobility and migration and contrast such effects with the influence of shifting population composition. We demonstrate that the effects of age and education differ, sometimes appreciably, by type of mobility. There has been little change in the impacts of demographic characteristics on the propensities to make particular types of moves. Instead, we find that the increasing share of longer distance movement has been due to secular changes, most likely traced to improvements in transportation and communication, and a favorable shift in population composition, especially increased educational attainment. The association of demographic characteristics with intercounty and interstate change of residence has remained stable.