The Traditional Structure-Process-Outcome Model

Avedis Donabedian has articulated what continues to serve as the unifying conceptual framework for quality measurement and assurance. His widely accepted model of structure, process, and outcome has guided two decades of research and program development (Donabedian, 1966, 1980, 1982, 1984, 1988a, 1988b, 1988c). We do not depart significantly from this conceptualization.

Structure

Structural measures, the characteristics of the resources in the health care delivery system, apply to individual practitioners, to groups of practitioners, and to organizations and agencies. They are essentially measures of the presumed capacity of the practitioner or provider to deliver quality health care, not of the care itself. Deficiencies in structural measures are not evidence of poor care (and certainly not of poor outcomes); they may, but do not necessarily, point to crucial areas requiring improvement or reform.

For health care professionals, these variables include demographic factors (e.g., age) and professional characteristics (e.g., specialty, licensure and certification, practice setting and style). For facilities and institutions, they include size, location, ownership and governance, and licensure and accreditation status. They can also include many physical attributes (e.g., special units and computer capabilities) and a large set of organizational factors (e.g., staff-to-staff or staff-to-patient ratios; employee morale and turnover).

Quality assurance programs acquire information on structural measures in several ways. The simplest is probably through mechanisms of licensure, certification, or accreditation that are maintained by states, professional associations, or third-party payers. Provider surveys can also provide relevant information.

Some observers question the relationship of structural measures to either process or outcome variables because of inadequate measures and little empirical evidence of direct connections; they tend to downplay the importance of structural characteristics of health care organizations as markers of quality. Nevertheless, over the last decade various elements of the quality assurance field have more explicitly emphasized accountability, governance, and lines of authority, especially for hospitals. Regulatory agencies such as states, voluntary associations such as the Joint Commission, and institutional quality assurance officials are much more likely to repose the ultimate responsibility for quality care in boards of trustees or directors and equivalent organizational executives. Consequently, structural measures that reflect organizational patterns, lines of authority, and communication



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