Economic gains from the 2004 EU accession round

Abstract

Employing a synthetic difference-in-difference estimator on regional data, we estimate that EU membership has increased per capita incomes by more than 30 percent, broadly in line with previous country-level estimates. While all regions that joined the EU benefited, we find substantial regional heterogeneity within countries. Regions with better financial access and stronger integration in value chains prior to accession benefited more from the new economic opportunities presented by the single market. Both capital accumulation and higher productivity contributed significantly, while employment effects were small. The estimated gains suggest that deep integration carries significant economic benefits, providing valuable lessons for future EU enlargement and regional integration efforts elsewhere.