International migration beyond gravity: a statistical model for use in population projections

Joel E. Cohen, Rockefeller University and Columbia University
Marta Roig, United Nations
Daniel Reuman, Imperial College London
Cai GoGwilt, Massachussets Institute of Technology (MIT)

International migration will play an increasing role in the demographic future of most nations if fertility continues to decline globally. This work shows that the spatial distribution of people strongly affects international migration. We modeled numbers of international migrants from any country or region to any other based on geographic and demographic independent variables only: the population and area of origins and destinations of migrants, the distance between origin and destination, the calendar year and indicator variables to quantify non-random characteristics of individual countries. The dependent variable, yearly numbers of migrants, was quantified by 43653 reports from 11 countries of migration from 228 origins and to 195 destinations during 1960-2004. The number of emigrants from an origin depended on both its population and its population density. The migration estimates generated by the model may be embedded in deterministic or stochastic population projections.