"This paper presents estimates of the rate of population redistribution to the core areas of 44 developing countries over the period 1950-80. Particular attention is given to the period 1970-80, a time during which the core areas of developed countries experienced substantial declines in their rates of net inmigration. The principal finding is that the core areas of most developing countries are still experiencing high and, in a number of cases, increasing rates of net inmigration." The author contends that "this finding confirms the developmental model of spatial concentration and dispersal and should lay to rest other explanations of deconcentration, including arguments that focus on diseconomies of absolute size in the core area or on fluctuations in the aggregate economy." The difference between the population growth rates of entire nations and of core areas is used as a measure of interregional migration. Data for the 44 countries and information on the data sources are included in appendixes.