There is currently heightened interest in optimizing health care through the generation of new knowledge on the effectiveness of health care services. The United States must substantially strengthen its capacity for assessing evidence on what is known and not known about "what works" in health care. Even the most sophisticated clinicians and consumers struggle to learn which care is appropriate and under what circumstances. Knowing What Works in Health Care looks at the three fundamental health care issues in the United Statessetting priorities for evidence assessment, assessing evidence (systematic review), and developing evidence-based clinical practice guidelinesand how each of these contributes to the end goal of effective, practical health care systems. This book provides an overall vision and roadmap for improving how the nation uses scientific evidence to identify the most effective clinical services. Knowing What Works in Health Care gives private and public sector firms, consumers, health care professionals, benefit administrators, and others the authoritative, independent information required for making essential informed health care decisions.