Abstract: | We examine two related questions that are key for understanding collaborative outcomes in complex governance systems. The first is the extent to which collaboration among policy actors depends upon their joint participation in policy forums. The second is how the scales at which these forums operate conditionally affect the likelihood of collaboration. We address these questions using data from a recent survey on actors’ collaborative interactions as well as their participation in climate change adaptation policy forums in the Lake Victoria region in East Africa. Exponential random graph models show that actors are more likely to collaborate if they jointly participate in policy forums. However, this effect weakens at progressively higher spatial levels at which forums operate. Similarly, collaboration is less likely among actors jointly participating in forums that sponsor decision making at the higher collective choice level rather than lower operational choice level. While policy forums may catalyze collaboration, our findings suggest that their capacity to do so may be subject to scale‐dependent transaction costs of political contracting. |