Based on an ethnographic study, this article investigates an attempt by a multidisciplinary group to employ pre-developed guidelines for producing a knowledge base that was to be used in a policy decision. The article contributes to previous studies of the development and use of knowledge-based guidelines and knowledge syntheses in policy-research collaborations. It is concluded that guidelines are inevitably characterised by informed ignorance, and that this informed ignorance is both an obstacle and a necessity for the successful employment of guidelines in policy processes.