; (2) are developed by a knowledgeable, multidisciplinary panel of experts and representatives from key affected groups; (3) take into consideration important patient subgroups and patient preferences, as appropriate; (4) are based on a systematic review of the existing evidence; (5) except in the case of diagnostic guidelines, provide a clear explanation of the relationship between care options and health outcomes; (6) except in the case of diagnostic guidelines, provide ratings of both the quality of evidence and strength of recommendation; (7) are reconsidered and revised when new evidence emerges