The notion that research may be carried out expressly to influence policy is still controversial to many researchers. Some feel quite strongly that research should not be limited and directed by the demands of policy makers. They assume that more is accomplished when research is unfettered and free to follow its own directions. However, providing research for the benefit of policy makers and the needs of a society is equally legitimate. In particular, some drug researchers bemoan their lack of influence on drug policy, believing that policy would be improved if their research findings were more central in decision making. After lengthy and difficult negotiations, policy recommendations to de facto depenalize the possession of cannabis for personal use were endorsed via the Belgian Law of 3 May 2003. The discussion about the new stipulations must be considered within the evolution in various European countries towards more tolerant policies regarding cannabis possession at the start of the twenty‐first century (e.g. Switzerland, Spain, UK). In my research I aim to understand how ‘evidence’ was used in the development of the cannabis law reform in Belgium and which (f)actors were at play. Is the development of the 2003 Cannabis Act based on (scientific) input or, so called, ‘evidence‐based’? Extensive academic output, using a diversity of approaches and analytical frameworks, has sought to systematize knowledge (or research) utilization categories and strategies. Most authors hold a positivist view resulting in an assumption that the relation between knowledge and policy is linear, direct or problem solving and, to a certain extent, predictable. Scientific inquiry is seen as the core knowledge production process. I follow a critical, constructivist approach assuming that social reality is rather produced and reproduced through actions and interactions between (powerful) people and the ‘third community’ (e.g. media, interest groups). This presentation will report on my considerations in developing (and testing) my ...