The value of consensus recommendations for improving clinical practice may be restricted by the limitations of the evidence on which they are based. When few high quality studies are identified for evaluation from the specific field of interest, selected 'transferable' evidence from comparable clinical situations may add important information. Such transferable evidence must be critically assessed for relevance to the objective of the recommendations, and must be clearly differentiated from specific evidence. In particular, systems for grading of recommendations must take into account the different types of evidence used, so as not to give equivalent weight to transferable and specific evidence without justification. In this article, we discuss the use of transferable evidence by the PROSPECT Working Group, which has developed a clinical decision support programme (www.postoppain.org) to provide evidence and recommendations for procedure-specific postoperative pain management.