International Migration Systems: Evidence from Harmonized Flow Data

DeWaard, Jack, Keuntae Kim, and James Raymer
Working paper no. 2009-07


We use harmonized data on bilateral migration flows between countries in the European Union (EU) from 2003 to 2007 to test whether international migration systems are structured according to “different hierarchies” per the expectations of migration systems theory (Zlotnik 1992:39). Migration systems theory requires evidence from data on migration flows for the determination of migration systems; yet available data of this sort lack a consistent metric given differences in national systems of data collection and with the timing criteria used to validate migrations/migrants. We use harmonized estimates of migration flows from the MIgration MOdeling for Statistical Analyses (MIMOSA) project, which combine the emigration and immigration reports of origin and destination countries into a single set of flows that are consistent and complete, to develop explanatory models estimating the size of migration flows in relation to socio-cultural, geopolitical, economic, and demographic covariates. Results from modified gravity models and fixed effects vector decomposition support two hierarchies—an explanatory hierarchy from the salience of factors associated with origin-destination pairs, and an exposure hierarchy which distinguishes the size of migration flows on the basis of the relative tenure of origin and destination countries in the EU. Our findings lend support to migration systems theory and constitute the first such evidence using harmonized data on migration flows.