There is growing concern over the inappropriate utilization of health care facilities. The high cost of hospital care and the apparent shortage of nursing home beds have focused attention on one aspect of this problem: the clinically unnecessary days (sometimes called "administrative days" or "ADs") spent in hospitals by patients who are awaiting placement in long-term care facilities. In this study, data from a 1976 Massachusetts Department of Public Health survey of patients backed up in hospitals were analyzed to determine the magnitude of the problem and to examine the influence of several major factors that had been hypothesized in previous studies to contribute to the backup. We demonstrate that the average delay of a patient found waiting in a "snapshot" survey (which is often used to estimate the magnitude of the problem) is significantly greater than the average delay experienced by a typical discharged patient. We show that there are at least two major factors that influence the delay time: nursing home preferences in accepting certain types of patients and nursing home occupancy rates in the hospital service area. Neither medical-surgical occupancy rate nor the number of AD patients waiting in the hospital was significantly correlated with the delay time.