How does the increasingly dense network of overlapping institutions in global governance affect the design of intergovernmental organizations (IGOs)? We argue that institutional overlap can unleash mimicking dynamics whereby states design new IGOs using the design of existing organizations that engage in similar issue areas and perform similar governance tasks for similar member states as templates. Using design templates from the reference group of overlapping institutions is a strategy for boundedly rational designers in situations of complexity because it reduces uncertainty and lowers the costs of identifying suitable institutional solutions. Overlap therefore increases the design similarity between new and pre-existing IGOs, specifically where pre-existing organizations have institutional designs that made them endure. Introducing a new measure of institutional overlap in global governance and new data on the design and governance tasks of the 534 IGOs from the Correlates of War Project, we corroborate our argument using regression analyses. Our results hold important lessons for theories of institutional design, regime complexity, and global governance more broadly.

全球治理中日益密集的重叠机构网络如何影响政府间组织 (IGO) 的设计？我们认为，制度重叠可以释放模仿动力，由此国家设计新的政府间组织使用现有组织的设计，这些组织参与类似的问题领域，并为类似的成员国执行类似的治理任务作为模板。使用来自重叠机构参考组的设计模板是有限理性设计者在复杂情况下的一种策略，因为它减少了不确定性并降低了确定合适的机构解决方案的成本。因此，重叠增加了新的和先前存在的政府间组织之间的设计相似性，特别是在先前存在的组织具有使它们经久不衰的制度设计的情况下。我们引入了全球治理中制度重叠的新衡量标准，以及来自战争关联项目的 534 个政府间组织的设计和治理任务的新数据，我们使用回归分析证实了我们的论点。我们的结果为制度设计、制度复杂性和更广泛的全球治理理论提供了重要的经验教训。