Policy decisions taken now can determine the room for manoeuvre of future generations for a very long term. Politicians and civil servants often only seem to be interested in short-term implications, however. A major focus on the short term does not provide sufficient stability and impetus for long-term structural measures. This is primarily an institutional issue. In this article, the authors discuss how to instil a long-term focus in day-to-day processes of policymaking.

Policy evaluation has two main functions: it should lead to policy oriented learning and facilitate accountability. Rendering account is considered an important democratic duty but is not very popular with politicians and, hence, public officials. Learning is popular, but in practice it is often difficult to organize or, indeed, witness.
This contribution addresses the question how, in both functions, policy evaluation could be better utilized. As a starting point we the tension between scientific and political rationality and the barriers associated with these different worlds to the development of knowledge.
As indispensable for sound and productive knowledge management in government the article outlines the importance of societal values, policy effectiveness as a research angle, and the independence of researchers at major evaluations. In addition, relevant research questions, high methodological quality, responsiveness, good timing, and clear and accessible reporting are indispensable. It is argued that these are by no means abstract notions but can be brought into real day-to-day practice.
The conclusion is that a knowledge agenda for policy evaluation that is based on the search for effective policy interventions and societal values can help to bridge politics and science.