SupplementThe US health-care system is experiencing a revolution, a major paradigm shift[1], as organizations "reinvent" themselves to put more emphasis on primary care and the holistic continuum of care than on illness care[2], as prepaid or capitated health plans rapidly gain market share in all geographical regions, and as health-care organizations [2][3][4][5], like other businesses [6], are deconstructing themselves through downsizing, re-engineering, and creating networks. Simultaneously, organizations that have embraced continuous quality improvement principles and strategies are experiencing incremental changes in their processes of care [7]. Clinicians may perceive these changes to be a veritable chaos, produced by data-free change strategies. Prediction of the future nature of the US health-care system is confounded by the lack of standardized clinical data elements and quality indicators, current telecommunications limitations, and the many complex, competing factors which are propelling change. Among these factors are concern for quality, the changing role of the consumer in health care, but, most especially, the concerted efforts to contain health-care cost escalation [2,8,9]. This article discusses challenges pertaining to these factors that providers, payers and policy makers must grapple with to shape the future US health-care system.First, consumerism and pursuit of market share challenge organizations to "reinvent" consumer-valued services and processes in a cost-effective manner that maintains or improves quality. Many such changes have been implemented without empirical data regarding the consequences of those changes. Research of the influence of various service delivery models on patient satisfaction and quality indicators is needed to help administrators and providers meet this challenge. Similarly, also needed is consumerism and the changing role of the consumer challenge providers to share information that meets their consumers' needs in a manner that they can use in making choices. This dimension of care continues to be a source of patient dissatisfaction. Research on the effectiveness of information sharing in various populations would help providers meet this challenge.Second, concerns for quality challenge organizations and providers to be accountable for improving processes and outcomes of care by decreasing practice pattern variation and associated differences in outcomes. Use of clinical practice guidelines has been initiated to help reduce practice pattern variation