Review of twenty years of research on medical care utilization.

A wide variety of issues in social distribution and system performance are approached through analysis of utilization, as shown by this review of twenty years of research. Utilization studies have been used to examine social norms with respect to dying and to geographical and class diffusion of access to the most useful diagnostic procedures. Prevention utilization is selected for special study but is difficult to analyze because both the boundary between prevention and treatment services and the unit of observation are ill defined. A series of studies of the class gradient in use of care under conditions of reduced barriers to care indicate that equity can be improved through program design even though deficits remain at this time. For health plans with social objectives, a stable low-user group presents a challenge to outreach rather than a source of financial comfort. Other work on utilization examines unnecessary care through study of interregional variation in surgical rates and the phenomenon of physician-induced demand; cost-sharing; the HMO model in its attempt theoretically to reconcile equity with cost-containment; the role of sex differences in utilization; and the influence of women's social roles and traditional/contemporary cultural relationships on access.