This article seeks external determinants of patterns of convergence or lion-convergence in EU's periphery by considering the selection strategies of the EU for the inclusion of various countries in different sets of policies as a powerful and understudied driver of convergence. The existing sets of policies form two different EU policy tracks, loosely termed 'proactive' and 'reactive' - their main difference being that only the former leads to EU membership, thus offering strong incentives for compliance that result ill convergence. The question that is, therefore, posed is: What drives the selection by the EU of countries for inclusion in the proactive track? The article contrasts two different answers to this key question: the 'differentiation by performance' theory, and that of 'differentiation by design'. The former argues that selection and inclusion of transition countries in the intensive 'proactive' policy track, and therefore in more expensive policies, followed their transformation efforts. The comparison of EU policies towards countries in Central and Eastern Europe and the Commonwealth of Independent States, however, supports the rival and less established differentiation-by-design thesis. The Conclusion is that EU selection and inclusion practices seem to have largely reflected the EU's own preferences and were therefore selectively responsive to transformation efforts from different groups of countries, thus providing evidence in support of the differentiation-by-design thesis.
