In education, as in other fields, there are often significant gaps between research knowledge and current policy and practice. While there are many reasons for this gap, one that stands out is that policy-makers and practitioners may simply not know about important research findings because these findings are not published in forums aimed at them. Another reason is that policy-makers and educational authorities may tend to apply only those findings that agree with and legitimate their preferred policies. Yet we hear often the mantra that policy and practice should be research based and informed by evidence. This claim relates to the interplay between the social realities of science, politics and educational practice and draws attention to knowledge production and application, processes of implementation, change and innovation. However, there are often different interests involved, different knowledge domains, political and economic interests, and legitimate questions can be raised with regard to what counts as ‘research’, what counts as ‘evidence’, who should define it, what are their implications for policy, and what kind of actions should consequently be taken to improve education for children and youth.