Previous studies increasingly acknowledge that international institutions do not exist in isolation, but regularly interact with each other. This interaction might induce mutual influence, affecting institutions’ development and performance. The following research adds to this debate by systematically analyzing the quantitative evidence on how interaction drives institutional design from a network perspective. Using cross–section data on international environmental agreements, the authors find support for their theoretical argument that regimes’ similarity in design as captured by the degree of legalization strongly depends on institutional interaction. While institutions that are well connected through direct or indirect links can disseminate “soft law” between each other, this does not apply to “hard law,” however. The authors explain this divergence with states’ concerns about binding–law commitments and sovereignty costs associated with the latter. This research may have important implications for studies of institutional interaction and of social networks in general.
