This paper surveys the impacts on the direction of research and scientists' working and publishing habits of a particular type of research policy initiative, research field evaluations commissioned by Research Councils in four Nordic countries. The data are based on interviews with approximately 90 scientists and scholars who had been subject to evaluation. The paper draws attention to differences of impacts between fields according to their type (disciplinary versus hybrid fields). A major finding is that the impacts were minimal. Nevertheless, the evaluated scientists had a positive view of the usefulness of the evaluations. They emphasized the value of the evaluations for the allocation of funds and for ‘keeping science straight’ by internal quality control. The paper highlights that these evaluations had multiple purposes and uses. It finishes with some overall conclusions of the impacts of these evaluations from the point of view of both the Research Councils and the evaluated scientists.