Guidelines offer concise instructions on which diagnostic or screening tests to order, how to provide medical or surgical services, how long patients should stay in hospital, or other details of clinical practice. Clinicians, policy makers, and payers see guidelines as a tool for making care more consistent and efficient and for closing the gap between what clinicians do and what scientific evidence supports. The most important limitation of guidelines is that the recommendations may be wrong (or at least wrong for individual patients).
Apart from human considerations such as inadvertent oversights by busy or weary members of the guideline group, guideline developers may err in determining what is best for patients for three important reasons. Scientific evidence about what to recommend is often lacking, misleading, or misinterpreted . Only a small subset of what is done in medicine has…
