Overlapping regionalism around the world: Introducing the overlapping regionalism dataset

Regional cooperation often leads to the establishment of regional international organizations (RIOs). Due to the increasing number of RIOs, their growing membership size and their broadening policy scope, RIOs frequently overlap with each other with regard to membership and mandate. Overlaps may lead to conflicts amongst affected organizations and potentially limit the prospects for regional prosperity and peace. Although overlapping regionalism has become ubiquitous in many regions, we do not systematically know the extent of the phenomenon. Therefore, the paper presents an original dataset about overlapping regionalism and introduces a typology of overlaps between two RIOs. The OVREG dataset includes both raw data of shared member states and policy competencies and information about distinct types of overlap between affected RIOs for 73 RIOs, 193 states and 344 policy competencies in the period between 1945 and 2020. A descriptive analysis of trajectories and patterns shows that overlapping regionalism in general and the different overlap types have spread over time and across world regions. Nevertheless, regional particularities persist. Thus, the OVREG dataset allows for examining the causes of overlaps, the potential negative consequences of overlapping regionalism and the variety of coping mechanisms at the disposal of affected RIOs.