Evidence-based care: 2. Setting guidelines: how should we manage this problem?

There are four steps in determining how to manage a clinical problem. The first is to formulate questions that are answerable; the second is to locate and synthesize the evidence needed to answer the questions; the third is to estimate the expected benefits, harms and costs of each option based on the evidence; and the fourth is to judge the relative value of the expected outcomes to conclude whether the benefits are worth the harms and costs. It is impractical to repeat these steps for every clinical decision. Therefore, implicitly or explicitly, physicians rely on guidelines, "rules" that simplify decision making about complex problems. If the methods used to develop a guideline are not explicit it is difficult or impossible to know how much confidence to place in it. Therefore, for common and important clinical problems, physicians should rely on guidelines that are systematically developed using explicit methods.