The Changing Structure of International Migration, 1960–2020

Micol Morellini , University of Oxford
Per Block, University of Zurich
Guy Abel, University of Hong Kong

Debates on the globalisation of migration often centre on whether international moves have become more geographically diversified or remain concentrated within a few major corridors, a dimension commonly referred to as ‘migration diversity’. Existing evidence of changing migration diversity at the global level is inconsistent, as different measures of diversity emphasise distinct aspects of migration systems, such as richness or evenness. This study re-examines global migration diversity between 1960 and 2020 using newly harmonised bilateral flow estimates covering 195 countries. We introduce a unified framework of diversity measures that assesses the richness and evenness of migration flows on a common scale and over time. We extend the framework with a population-adjusted reference that reflects countries’ demographic capacities to send and receive migrants: by comparing this population-adjusted reference with observed migration structures, we can distinguish genuine diversification of flows from changes driven solely by country size. We compute diversity profiles for each decade at global, regional, and country levels to trace the sources of aggregate change. Preliminary results suggest a gradual transition from a highly uneven migration structure (dominated by a few large corridors) to more proportionate and demographically balanced configurations, especially after 1990. The diversification of international migration thus appears to stem from the emergence of novel migration corridors and a demographic rebalancing of mobility opportunities across countries, proportional to their size. These findings underscore the importance of integrating population size into diversity measurement, particularly in the context of cross-country and temporal comparisons.

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 Presented in Session 66. International Migration