Although financing the expanding health care costs associated with the management of serious and complex medical conditions remains a pressing concern, so too are issues addressing quality of care for the growing numbers of individuals with serious and complex medical conditions. Receipt of high-quality care is essential to sustain or restore the health and functioning of millions of Americans with serious and complex medical conditions. Quality of care has been defined as ''the degree to which health services for individuals and populations increase the likelihood of desired health outcomes and are consistent with current professional knowledge" (Institute of Medicine, 1990).
A number of initiatives including the Institute of Medicine's National Roundtable on Health Care Quality and the President's Advisory Commission on Consumer Protection and Quality in the Health Care Industry have focused on major sources of compromise in the quality of care delivered to patients (Institute of Medicine, 1999; President's Advisory Commission, 1998b). Although most Americans receive high-quality health care, a significant number experience substandard care regardless of the type of health care delivery system. Due to the potential for a higher level and frequency of involvement with the health care delivery system, persons with serious and complex conditions could be considered at particular risk for errors in the care delivery process.
Four major categories of errors contributing to substandard health care quality have been identified: (1) avoidable errors; (2) underutilization of services; (3) overuse of services; and (4) errors associated with wide variations in health care practices, including regional and small-area variations. Avoidable errors refer to injuries sustained by patients during the course of their care. Some patients die prematurely as a result of such injuries. Underutilization of health care services has also been cited as a major factor contributing to the delivery of poor-quality health care service that can lead to detrimental outcomes associated with functional status and quality of life and may also result in premature death.
Underutilization occurs when patients fail to receive an intervention whose benefits outweigh its risks. Overuse of health care services can also undermine the quality of care. Specifically, overuse refers to the delivery of a health care intervention with a higher likelihood of risk than potential benefit to patients. Finally, errors associated with variations in health care practices have been noted for different patient populations, health care providers, and health care delivery systems.
A number of studies reveal that characteristics of patient populations are associated with variations in the quality of health care. For example, compromises in care have been noted for the elderly, women, members of racial or ethnic minority groups, and members of low socioeconomic or low educational attain-