Disaggregation of Net Migration to Improve Projections by Age and Sex

James Raymer, Australian National University

Most population projection models require age- and sex-specific information on net migration totals as a key demographic component of population change. Existing methods for predicting future patterns of net migration by age have proven inadequate. The main reason is that methods applied to model net migration are unable to distinguish factors influencing the inflows from those influencing the outflows. In this paper, a prediction method that models the age- and sex-specific flows of in-migration and out-migration to derive age-specific net migration is proposed. By including models for in-migration and out-migration, even in the absence of data on such flows, the resulting net migration predictions are greatly improved over existing methods that only model the net migration totals. To demonstrate the effectiveness of the method, two illustrations are presented. The first is age-specific projections of net migration for counties in the state of Washington in the United States. The second is projections of age- and sex-specific international migration for all countries in the world, recently adopted by the United Nations Population Division for the 2024 revision of the World Population Prospects.

Keywords: International Migration, Internal Migration and Urbanization, Population projections, forecasts, and estimations

See paper.