Organizational institutionalism has shown how institutional entrepreneurs can introduce new logics into fields and push for their broader acceptance. In academic science in the United States, however, market logic gained strength without such an entrepreneurial project. This article proposes an alternative “practice selection” model to explain how a new institutional logic can gain strength when local innovations interact with changes outside the field. Actors within a field are always experimenting with practices grounded in a variety of logics. When one logic (...) is dominant, innovations based on alternative logics may have trouble gaining the resources they need to become more broadly institutionalized. But if a changing environment starts systematically to favor practices based on an alternative logic, that logic can become stronger even in the absence of a coherent project to promote it. This is what happened in US academic science, as growing political concern with the economic impact of innovation changed the field’s environment in ways that encouraged the spread of local market-logic practices. (shrink)