During the 1970's the South and West census regions accounted for 89.9 percent of incremental U.S. population and 72.5 percent of incremental nonagricultural employment. These figures are sharply higher than corresponding figures for any other decade in U.S. history. For example, during the 1930's the South and West gained 65.4 percent of incremental national population, which was the highest share previously recorded. The immediate cause of the interregional population shifts is fairly heavy net out-migration from the Northeast and North Central regions to the South and West, combined with birth rates that are near historical low levels. Interactive relationships that cause employment growth and migration to reinforce one another are probably operating, but these relationships are not well understood. They are the focus of this paper. Using a new and unique set of time-series data on migration and employment, we develop and estimate a time-series model of migration and employment growth for each of 171 U.S. regions. Our primary emphasis in this paper is on the 57 major metropolitan

Utilizing a utility-maximizing, Roy-type, discrete choice model of worker location in Canadian provinces and U.S. states that incorporates returns to skill, amenities, fixed costs, distance, language, and border effects, we find that individuals with higher skills migrate to areas with higher returns and that the 49th parallel attenuates migration. Simulations indicate that equalizing returns in the two countries has a modest effect on cross-country migration; however, reductions in border effects tend to have large nonlinear effects on it. Our results confirm the qualitative results of previous research emphasizing the importance of returns to skill and border effects in migration decisions.

In this paper the authors have theoretically derived a net migration equation and estimated it using time-series data for 51 regions over the period 1971-88. The results indicate that the dynamic response of net migration is stable and is significantly related to stock equilibrium changes induced by amenity differentials, relative employment opportunities, relative real wages, and industry composition. Moreover, the explicit linkage of stock equilibrium to stable dynamic flows in the model ensures that any stock disequilibrium will generate a finite migration response sufficient to attain a new stock equilibrium. The estimated parameters determine the speed at which net migration re-establishes stock equilibrium. Coauthors are Dan S. Rickman, Gary L. Hunt, and Michael J. Greenwood. Copyright 1993 by MIT Press.