A new systematic review of evidence examines the effectiveness of the patient-centered medical home (PCMH) model on quality of care, affordability, and patient and professional experience. The review informs health care reform policy and program efforts and offers guidance on how to structure future evaluations. Although the evidence on PCMH precursors is inconclusive because of inadequacies in evaluation designs or analytic methods, the review found some favorable evidence on quality of care, hospital use, and patient experience among older, sicker patients served by these precursors.