Why has hospital length of stay declined? An evaluation of alternative theories.

This study evaluates the importance of several potential determinants of observed decreases in hospital stays for patients undergoing each of 11 surgical procedures using a panel of 521 hospitals covering 1971-1981. Observed decreases in stays for these patients were substantial. If anything, the complexity of cases treated rose and, for this reason, stays should have risen. Neither state prospective payment nor Professional Standards Review Organization programs reduced stays and may have increased them. Competitive influences had no effect. Changes in payer mix and hospital ownership were too small to have had an impact. Evidently the decreases were mainly due to improvements in surgical technique and other changes in medical practice. Several implications for Medicare's new payment system are discussed.