Evidence-based policy-making is regarded as an instrument for rationalizing policy-making. It may however also be seen as a tool to promote policy integration, to achieve cross-cutting objectives, such as sustainable development, and to address large-scale global challenges, such as climate change. In that it takes account of a broad range of potential regulatory impacts and fosters consideration of otherwise neglected aspects in decision making, evidence-based policy-making has the potential to increase reflexivity in political decision-making. This paper analyzes evidence-based policy-making as sitting between the poles of alleged rationalization of the political process and enhanced reflexivity which results from the larger number of aspects considered in decision-making. Even if both models seem to be diametrically opposed at first, a closer look on the types of policy problems to be addressed reveals that the evidence and knowledge needed in policy assessment are different—ranging from factual evidence to reflexive forms of knowledge that result from dialog and deliberation between societal actors.