Seeing the Hidden Part of the Iceberg : Gauging the Real Dimension of International Migration

The reliability and comparability of international migration statistics are among the of the most important statistical issues, due to its consequences on the correct dimensioning of the migration flows and stocks, and on the design on timely and effective policy measures to manage this phenomenon and contain its possible adverse outcomes. This paper makes an assessment of the migration statistics provided by Eurostat, reveals the most prominent discrepancies between stock and flow data, makes a summary of the main issues that affect the quality and completeness of the migration data, and identifies some solutions in order to improve the comparability, reliability and completeness. There is no one-size-fits-all solution, but an eclectic mix which extends the use of administrative and private data, matches the data coming from distinct sources in order to assess the stocks and flows of international migration, harmonizes the way in which data is compiled and reported by different countries, matches observed flows with (demographic) stock-based estimates, provides consistent estimates of the bilateral migration flows between countries, and improves the measuring of temporary and illegal/undeclared migration. Another recommendation is to preserve the existing migration data along with the improved estimates in order to gauge the specifics of international migration in the reporting countries and to properly inform national public policy measures