A technique is described which circumvents the difficulty in obtaining reliable judgments by clinicians on cases of inappropriate use of hospital beds. By application of the Delphi method of measuring group expert opinion, convergence was achieved in the estimate, by four physicians, of the total number of bed days wasted on a medical ward during a period of two weeks. Cases of possible misutilization were identified by the author and a second study was designed to measure the effect on the physicians' behavior of her presence on the ward (Hawthorne effect). It is suggested that review of cases of misutilization by the Delphi method could be used in the continuing education of physicians.