The Comparative Parliamentary Democracy project examines West European parliamentary politics from a principal-agent perspective. The project involves thirty-five scholars from Western Europe and the Americas. It has made both conceptual and empirical contributions in the fields of comparative politics, parliamentary democracy in general and coalition politics in particular. In this report, the project leaders present the project, its ￜstructured collaborationￜ approach and share some observations on the practice of conducting a large-scale cross-national project.