Why Do Interest Groups Organise Themselves as They Do?

Empirical studies demonstrate that the extent to which membership-based interest groups connect with their members and make them an asset in their policy activities varies significantly. Similarly, not all groups have the structures to articulate and efficiently transfer the preferences of members to policymakers. This ability to simultaneously connect with members and efficiently interact with policymakers, and thus function as a transmission belt, is a matter of organizational structure. However, we have scarce knowledge on how interest groups are internally structured and, more importantly, why are they organized in a certain way. This paper addresses these questions by considering two different – but complementary – approaches. On the one hand, from a rational perspective, the organizational structure of interest groups might be explained by the transactions costs they are subject to when pursuing organizational goals. On the other hand, sociological institutionalism emphasizes that interest groups do not operate in isolation and, thus, institutional and environmental forces are expected to determine why certain organization structures are prioritized over others. The paper explores these questions with qualitative data from semi-structured interviews among the leadership of prominent groups involved in the health domain at the EU level. Importantly, the study includes groups that vary in nature – i.e., business groups, professional associations, and citizen groups – as well as in organizational form. The findings will contribute to a better understanding of the antecedents of interest groups' organizational structures, which have a direct effect on the potential contribution of these political organizations to (supra)national governance systems.