Disaggregating the historical demographic sources of regional foreign-born and native-born population growth in the United States: A new method with applications

In this paper we offer a general method for analysing the demographic processes that contribute to population growth and redistribution in a multiregional system. The method incorporates a historical perspective that can be used to trace dynamic population processes as they evolve over time. It uses an open multiregional projection model framework for identifying the contributions to regional growth made by each of the principal demographic components of change: fertility, mortality, immigration, emigration, in-migration and out-migration. At the same time, the method recognises the importance of disaggregating the native-born and foreign-born populations. Available public data and indirect estimation techniques are used to develop the data inputs for the projection model, with which we reconstruct the regional population changes for each five-year period between 1950 and 1990. Regional growth rates for the foreign-born and native-born populations are partitioned into the separate demographic components of change, and the projection model identifies the separate contributions to regional growth made by each population. This allows a direct comparison of the impacts of immigration with those of corresponding native-born contributions effected through internal migration and natural increases. Finally, application of the method allows us to identify the contribution that recent (post-1965) immigrant cohorts have made to the composition of the youngest age groups in each region, and also to simulate the impacts of zero immigration scenarios on regional growth