Evaluates the quality of postsurgical care provided by 20 AF hospitals. Information is provided for patients treated in AF facilities during calendar years 1966 and 1967--approximately 50,000 surgical cases. The records provide each patient's postsurgical length of stay, complication record, and a detailed medical description. The 20 hospitals are compared with respect to length of stay and incidence of complications. Attention is given to variation in patient characteristics from hospital to hospital so that evaluative measures developed reflect the activities of the health-care delivery unit and not the underlying differences in the patients. A finding of the study is that among the hospitals there exist differences that cannot be accounted for by variation in patient mix or by statistical error. The analysis shows that explanations normally given to account for apparent institutional differences are inadequate. 92 pp. Ref.