This article addresses the role of science and science advisory bodies in modeling practices for the support of policy-making procedures in the Netherlands in the field of health care. The authors show, based on a detailed investigation of a prestigious interdisciplinary modeling project in which an economic care model was developed for governmental use, that science advisory bodies are entangled with the policy actors they advise in what we call boundary configurations. Boundary configurations are strongly situated interconnections between science advisory (...) institutes and policy institutions that share a specific approach to problem definitions and methods and that are embedded in specific social, discursive, and material elements. Importantly, as the case study shows, such boundary configurations shape the kind of science, and related, the kind of social and political theories about the world, that is effectuated in modeling practices. In this case study, the boundary configuration in which economic experts and policy makers participated contributed to the articulation of health care in terms of a market-based policy program for the health care sector. (shrink)