Understanding Internal Migration to Urban Areas in Developing Countries: Differences and Consistencies across Urbanization Stages and Historical Periods

The literature on internal migration presents ambivalent measures of migration. The “migration-defining” spatial boundaries and time periods are often inconsistent among data collected in different countries which hinders meaningful cross-national comparisons, as well as among censuses and surveys collected for the same country which prevents consistent urban in-migration estimations useful for urban population estimation and projection over time. Meanwhile, the measures of urbanization also vary across countries and data sources. This paper attempts to compare and consolidate various census microdata and surveys for urban in-migration and population estimates, as well as satellite data for consistent measurement of urban development. Using hundreds of millions of records from 152 census microdata samples from the International Integrated Public Use Mirodata Samples (IPUMS-I) and 208 Demographic and Health Surveys (DHS) for 84 developing countries in Africa, Asia and Latin America collected from 1970s to 2022, as well as satellite data that measures built-up areas based on the Global Human Layers(GHSL) from 1975 to present, this paper seeks to provide a comprehensive overview of historical trends in urban in-migration patterns by age, gender, education as well as its correlation with urbanization(in terms of both population change and urban development measured by built-up levels) at both the subnational and national level. Using mixed-effects regression models that controls for subnational and national-level population and economic conditions, as well as varied migration-defining spatial units, this paper also presents empirical evidence on how prevalence of migration to urban areas changes along urbanization stages, as well as how the relative role of migration in contributing to urban population and urban development shifts over time. Lastly, with datasets available before and after Covid-19 for 21 selected countries, this paper also attempts to show migration to urban areas might have changed due to large-scale public crises.