Bilateral international migration flow estimates for 200 countries

Data on stocks and flows of international migration are necessary to understand migrant patterns and
trends and to monitor and evaluate migration-relevant international development agendas. Many
countries do not publish data on bilateral migration flows. At least six methods have been proposed
recently to estimate bilateral migration flows between all origin-destination country pairs based on
migrant stock data published by the World Bank and United Nations. We apply each of these methods
to the latest available stock data to provide six estimates of five-year bilateral migration flows between
1990 and 2015. To assess the resulting estimates, we correlate estimates of six migration measures
from each method with equivalent reported data where possible. Such systematic efforts at validation
have largely been neglected thus far. We show that the correlation between the reported data and the
estimates varies widely among different migration measures, over space, and over time. We find that
the two methods using a closed demographic accounting approach perform consistently better than the
four other estimation approaches.