A one-day study was conducted to confirm evidence of disagreement about which physician was responsible for the care of patients in a teaching hospital. Sixteen percent of the patients reported the responsible physician as someone different from the physician listed on their medical record, and 13% could not provide any physician's name. Significant disagreement was also discovered between the name given by the charge nurse, the patient's identification band, and the face sheet on the patient's chart. Twenty-nine percent of the charts reviewed revealed no documented involvement by the responsible physician within the previous ten days. As a result of the study, the hospital changed its documentation procedures and the hospital and the medical school became aware of the need to improve monitoring of supervision of student physicians.