A study of consumer knowledgeability about medical care services and its effect on the role consumers might play in decisions affecting resource allocation, especially whether competition and/or cost-sharing strategies should be pursued or whether regulatory strategies are more promising. An important goal of the study was to derive a scale that would permit measurement of the extent of consumer knowledge. Analyses of a ten-item questionnaire administered to nonaged persons showed that consumers are knowledgeable about some areas of medical care and uninformed about others. If a procompetitive medical care strategy is pursued, consumers need to be educated about board certification, staff privileges, and other factors pertinent to choosing a regular source of medical care. Factor analyses indicated that a substantial amount of information from item responses can be summarized in a multi-item scale that is reliable and valid as a measurement of patient sophistication.