Conceptualizing and evaluating how international organizations collaborate

International organizations (IOs) are increasingly being called upon to work with each other and with other actors, but little is known about how to evaluate the effectiveness and outcomes of these interactions. This article introduces a special issue and research project on ways of conceptualizing, analyzing, and evaluating how IOs partner, collaborate, or work together in other ways. We bring together different disciplinary perspectives on evaluating and researching collaborative relationships. We define the key concepts of collaboration, coordination, cooperation, and convening, and argue that the differences matter in substantive ways. We propose an analytical framework for evaluating and researching IO collaborative relationships comprising the composition of the actors, the objectives, the design features, and the exogenous factors. We discuss how collaborative relationships can and should be purposefully designed, analyzed, and evaluated and propose approaches to do so, emphasizing the need to complement assessments of outputs and outcomes with attention to trust and processes that nurture relationships. Our larger aim is to enhance understanding of how to make international and other organizations more effective collaborators.