This article introduces a journal supplement evaluating the country's first national demonstration of the patient-centered medical home (PCMH) concept. The PCMH is touted by some as a linchpin for renewing the foundering US health care system and its primary care foundation. The National Demonstration Project (NDP) tested a new model of care and compared facilitated and self-directed implementation approaches in a group-randomized clinical trial. The NDP asked what a national sample of 36 highly motivated family practices could accomplish in moving toward the PCMH ideal during 2 years within the current US health care payment and organizational system. Our independent evaluation used a multimethod approach that integrated qualitative methods to tell the NDP story from multiple perspectives and quantitative methods to assess and compare aspects that could be measured. The 7 scientific reports presented in this supplement explain the process, outcomes, lessons, and implications of the NDP. This introductory article provides context for making sense of the NDP. Important context includes the evolution of the PCMH concept and movement, the roots of the NDP and how it developed, and both what is valuable and what is problematic about family medicine and primary care. Together, the articles in this supplement show how primary care practices and the concept of the PCMH can continue to evolve. The evaluation depicts some of the early effects of this evolution on patients and practices, and shows how the process of practice development can be understood and how lessons from the NDP can inform ongoing and future efforts to transform primary care and health care systems.
