listed in Table 2, they will help those reviewing care to identify appropriate care more accurately.

In addition to following a careful analytic strategy in creating guidelines, developers should present their work to clinicians in ways that reflect the rigor of this approach and its emphasis on reasoning and critical analysis. Thus, the product of the process should not be perceived solely as information but more generally as an explication of the thinking processes that should be used in evaluating and applying that information. If guidelines are perceived only as information, they may very well be used (or rejected) as the "cookbooks" that many physicians decry. They will also not achieve their potential as educational tools.

In fact, few guidelines today provide any formal projections of health benefits and harms, any explicit treatment of patient preferences, or any estimates of the cost implications of their recommendations, certainly not in comparison with alternative practices. Most also lack explicit assessments of the strength of the evidence behind their recommendations. In addition, the educational opportunities implicit in guidelines cannot be fully exploited because the evidence and rationale for the guidelines are often not presented. Many of the future directions endorsed by this committee depend on better performance in these areas.

The committee recognizes that the development strategy recommended here is highly demanding and that some, perhaps most or all, guidelines will never fully achieve the ideal. It also recognizes the considerable gaps in empirical information about the natural history of many diseases and conditions, about health outcomes for many diagnostic or therapeutic interventions, and about the costs of providing those (or alternative) interventions. Nonetheless, if developers of practice guidelines make serious, persistent efforts in the directions recommended here, their products should become substantially more valuable and credible.

Although developers of guidelines have considerable room for improvement in the use of existing techniques, the methods for guidelines development are themselves in need of refinement. Given its emphasis on evidence, outcomes, and patient preferences and its concerns about the impact of guidelines on the quality and costs of health care, the committee focused on six questions of methodology:

1. means for setting priorities among topics for guidelines development;

2. procedures for securing thoughtful and useful statements of expert judgments;

3. methods for analyzing and rating scientific evidence;