To heed the recent calls for more inquiries into the endogenous nature of governance decisions, this study aims to develop a comparative perspective on the performance implication of the project interface design in the context of international scientific cooperation. Using Heckman's two-stage model in a sample of 217 international scientific cooperation projects sponsored by the Taiwanese government, this study shows that project performance characterized by the collective knowledge creation is explained more by team competence and inter-team social capital than by the project interface choice per se. Furthermore, the knowledge co-creation performance is impaired in the presence of project interface misfit, either over- or under-guarding the knowledge exchange in science cooperation. The findings not only yield implications for managing international cooperation in scientific research but offer comparability and equivalency with the organization-level studies characterized by knowledge exchange/creation and governance difficulties.