This review is part of a series of reports, Closing the Quality Gap: Revisiting the State of the Science, commissioned by the Agency for Healthcare Research and Quality (AHRQ). The series provides a critical analysis of existing literature on quality improvement strategies and issues for topics identified by the 2003 Institute of Medicine report Priority Areas for National Action: Transforming Health Care Quality.1 As part of its charge to continuously assess progress toward quality and to update the list of priority areas, AHRQ identified people with disabilities as a priority population. Health care for people with disabilities can present special challenges. For example, medical problems can be exacerbated or complicated by the presence of other medical, psychological, economic, and social problems. Likewise, the management of medical problems can be complicated by disability. Thus, optimal care requires coordination of services from various sectors to maximize the function and quality of life of a person with a disability. Since the care outcomes of function, quality of life, and community integration are interdependent, service coordination may need to span the spectrums of both care and support services (e.g., medical care and schools or social agencies). Coordination of care, with attention to the intersection of medical and social services, is congruent with recent policy attention on integrated care and medical homes. This review examines how health care outcomes have been assessed for people with disabilities. Our report seeks to improve shared understanding among a broad audience of researchers, clinicians, and policymakers with varied exposure to disability outcomes or quality improvement research. We begin by discussing outcome measurement issues and exploring conceptual frameworks for thinking about measuring outcomes for research and quality improvement efforts. We examine the diverse perspectives that researchers grounded in different fields bring to bear on what and how to measure. As with all frameworks that deal with complex concepts, the categories, paradigms, or classes we present are at best "ideal types" rather than simple designations with clean boundaries. Our Key Questions (KQs) focus on the quality assessment component of quality improvement. Using the levels-of-analysis framework, we examined outcome measures for medical care and care coordination for people with disabilities, with an emphasis on outcome measures at the level of the individual rather than the population. Key questions include: KQ1. How are outcomes assessed for people with disabilities living in the community in terms of basic medical service needs? KQ1a. What general population outcomes have been validated on and/or adjusted to accommodate disabled populations? KQ1b. What types of modifiers or case-mix adjusters have been used with the general population outcomes to recognize the special circumstances of people with disabilities? KQ1c. What are key parameters for measuring processes related to basic service care access for people with disabilities? KQ2. What measures have been used to assess effectiveness of care for people with disabilities living in the community in the context of coordination among health providers? KQ3. What measures have been used to assess effectiveness of care for people with disabilities living in the community in the context of coordination between community organizations and health providers?