The expansion of the EU in May 2004 to include 10 New Member States (NMS) made it possible for workers in some Central and Eastern European countries to take up work in the EU-15. Some East to West migration was anticipated as a consequence of EU enlargement due to the income gap between most EU-15 and NMS countries. However, the pattern of immigration across the EU-15 has turned out differently from expected; in part because of transitional restrictions on labour mobility imposed in many of the EU-15 countries (see e.g. Boeri and Brücker, 2005). Here we illustrate the potential macroeconomic impacts of the migration flows that are likely to have come as a result of EU enlargement. Clearly it is difficult to measure what migration might have happened had the EU enlargement in May 2004 not taken place, and hence to measure the change in migration from EU enlargement. This is for two reasons. First, there are relatively few data available on migration post enlargement to be able to disentangle an explicit EU enlargement effect. Second, the data that exist are not necessarily comparable, across countries and time, or comprehensive
