This article provides a concluding comment on the symposium focusing on Donald P. Green, Soo Yeon Kim, and David H. Yoon's “Dirty Pool.” Although the perspectives offered by the three sets of authors participating in the symposium differ starkly, my view (supported by conversations with the authors and additional analyses and debates among all involved) is that there is now a large area of underlying agreement. I describe this agreement by first illuminating Green, Kim, and Yoon's fundamental contribution in understanding and high lighting the role of heterogeneity in dyad-level studies of international conflict. I then describe the limitations in their revised analytic strategy, including those raised by John R. Oneal and Bruce Russett and by Nathaniel Beck and Jonathan N. Katz. I also offer suggestions for future researchers, methodologists, and data collectors.

In this article we summarize the empirical results of the Rational Design project. In general the results strongly support the Rational Design conjectures, especially those on flexibility and centralization; some findings are inconclusive (in particular, those addressing scope) or point toward a need for theoretical reformulation (in particular, the membership dimension). We also address the broader implications of the volume's findings, concentrating on several topics directly related to institutional design and its systematic study. First, we consider the trade-offs in creating highly formalized models to guide the analysis. Second, our discussion of the variable control is a step toward incorporating “power” more fully and explicitly in our analysis. We also consider how domestic politics can be incorporated more systematically into international institutional analysis. Finally, we initiate a discussion about how and why institutions change, particularly how they respond to changing preferences and external shocks. We conclude with a discussion of the forward-looking character of rational design.