The purpose of this article is to discuss and describe various measures of quality, quality indicators, and uses of information on quality with specific reference to the role or purpose of assisted living. We reviewed a variety of major studies of assisted living quality. We elaborated models of assisted living based on differing goals or claims made for it by providers and policy makers. We then searched for available quality measures that might indicate whether assisted living was meeting those goals or living up to those claims. Any meaningful concept of "quality" must embrace a variety of dimensions, including quality of care, quality of life, the physical environment, and resident rights. The ability to use a multidimensional concept of quality is complicated by the lack of consensus, confusion, and disagreement among consumers, providers, and regulators about the role of assisted living. This disagreement significantly confounds the task of comparing quality among assisted living settings and between assisted living and other types of long-term care. We propose ways that researchers may compare quality along dimensions claimed to be intrinsic to assisted living as part of an effort to inform consumer information systems, quality monitoring and assurance systems, and policy-relevant research. Such comparisons would vary, depending on the intended use of the indicators and role defined for assisted living. However, all uses contain structural, process, and outcome quality indicators, including direct feedback from interviews with residents that go beyond satisfaction measures.