Throughout the history of the development and use of medical technologies (phar-maceuticals, laboratory tests, invasive and noninvasive procedures, and medical devices), physicians and their patients have been the primary assessors of a technology's worth. If a drug, test, or procedure produces consistent beneficial effects, with little or no risk, then such a technology is commonly added to the clinician's arsenal of weapons against illness and disease. Academic researchers, however, with their keen desires to find new and better ways to diagnose, treat, and cure, are relied upon to produce evidence documenting a technology's efficacy. Others engaged in technology assessment activities—from their own perspectives—include manufacturers, who produce data showing the value of the products they hope to sell; hospitals that wish to make cost-effective purchases; and government agencies, with mandates to protect the public and to spend public dollars wisely. Still, it is the practicing physician who ultimately judges a technology's value based upon its use in individual clinical situations. Until very recently, with the apparent adequacy of these evaluative methods, medical professional societies were not required to enter the technology assessment arena.