Since the mid-1990s, flexible or differentiated integration (DI) has become a “hot topic” of academic
and policy debate in the EU. By DI, we mean the territorially fragmented validity of rules in a polity.
In the literature of European integration, it is generally assumed that the considerable territorial and
functional expansion of the EU in recent times has increased heterogeneity in the EU, and that this
heterogeneity is likely to generate demand for DI.
Despite the perceived political and scientific relevance of the topic, the state of research is
characterized by a scarcity of data and of theory-oriented explanatory analysis. In addition to a large
amount of prescriptive or policy-oriented work, academic contributions in political science have
focused on differentiation in treaty law and have largely been limited to conceptual work, case
studies, and ad hoc-explanations. Our workshop is intended to contribute to filling the gaps and
shortcomings in existing research.
As a result of this workshop, we hope to gain a better understanding of the extent, development,
and conditions of differentiated integration in Europe, to encourage further research on this topic,
to create a productive network of researchers and to start work on common publications in the
We invite theoretical or theory-oriented empirical papers on differentiated integration in Europe.
Case studies or comparative analyses may focus on specific policy fields, countries, time periods, or
types of differentiation. We also welcome papers analyzing the differentiated integration of nonmember states with the EU and papers comparing DI in the EU with other political systems or