Many organizations and individuals are interested in care coordination, particularly as it relates to concerns about inefficiencies and suboptimal quality in the U.S. health care system. The Institute of Medicine identified care coordination as one of 20 national priorities for action to improve quality along its six dimensions of making care safe, effective, patient centered, timely, efficient, and equitable. The burgeoning number of aging Americans with chronic illnesses and the increasing complexity of care create challenges to coordination experienced at every level-the patient, the clinical practice, and the system. Care coordination interventions are particularly attractive in that they have the potential to improve both efficiency and quality. This final Evidence Report in the series "Closing the Quality Gap" by the Stanford-UCSF Evidence-based Practice Center addresses the topic of care coordination. This report describes our working definition of care coordination, summarizes some of the evidence about the effectiveness of care coordination interventions from systematic reviews, and presents relevant frameworks for the development and evaluation of future interventions. This approach may be useful to system-level policymakers, service-level decisionmakers, and patients. System-level policymakers have responsibility for paying for health care services for large numbers of individuals and making decisions about how to coordinate care at a system level in ways that minimize their financial risks and maximize the health care received by their population of patients. Service-level decisionmakers are involved in providing health care services to individual patients or a panel of patients, and therefore tackle care coordination at the service delivery level. Depending upon the particular local environment, they make decisions related to care coordination to maximize health care outcomes and use resources efficiently. Patients and their families are assuming increasingly active roles in health care decisionmaking and are navigating an increasingly complex health care system with consumer-driven health plans and other efforts to involve them more. The patient often experiences first-hand problems of coordination, and therefore may be just as interested as health care professionals in understanding care coordination. The key questions addressed in this Report relate to four areas: Ongoing Efforts in Care Coordination and Gaps in the Evidence: What aspects of care coordination are of greatest interest to healthcare decisionmakers? What are the key gaps in the care coordination evidence base? Definitions of Care Coordination and Related Terms: What definitions exist for care coordination? What definition could be formulated to apply to systematic reviews? Review of Systematic Reviews of Care Coordination Interventions: Which care coordination interventions have been evaluated by systematic reviews and how were they defined? What is the evidence regarding the health benefits of these care coordination interventions as summarized in the systematic review(s)? In particular, is the effectiveness of care coordination interventions related to the setting in which care is being coordinated, the component of care being coordinated, or the type of disease or patients for whom care is being coordinated? Have the costs of care coordination interventions been evaluated in any of these systematic reviews, and if so what is known? Conceptual Frameworks and Their Application to Evaluating Care Coordination Interventions: What concepts are important to understand and relate to each other for future evaluations of care coordination? What conceptual frameworks could be applied to support development and evaluation of strategies to improve care coordination? What measures have been used to assess care coordination? How do these frameworks relate to quality improvement strategies evaluated in the previous Closing the Quality Gap series reports?