Unlabelled: Quality management programs have used several data reporting sources to identify adverse perioperative outcomes. We compared reporting sources and identified factors that might improve data capture. Adverse perioperative outcomes between January 1, 1992, and December 31, 1994, were reported to the Department of Anesthesiology Quality Management program by anesthesiologists, hospital chart reviewers, and other hospital personnel using incident reports. The reports were compared for preoperative health status, severity of outcome, and associated human error. Subsequently, personnel representing the various sources were surveyed regarding factors that might affect their reporting of adverse outcomes. Of 37,924 anesthetics, 734 (1. 9%) adverse outcomes were reported, 519 (71%) of which were identified by anesthesiologists, 282 (38%) by chart reviewers, and 67 (9.1%) by incident report. There was no statistically significant difference in reporting rates by anesthesiologists according to preexisting disease, severity of outcome, or presence of human error. Thirteen cases involving human error, however, resulted in disabling patient injury, with a higher rate of self-reporting for these cases (92%, P < 0.05). Rates of reporting by chart reviewers varied (P < 0.05) according to severity of patient illness and severity of outcome. Incident reports identified only 67 adverse outcomes (9.1%), but included a significantly higher percentage of the adverse outcomes involving human error (23.3%, P < 0.05). Twenty attending anesthesiologists, 15 resident anesthesiologists, 29 operating room nurses, 19 postanesthesia care unit nurses, and 6 hospital chart reviewers responded to the survey. Only the potential to improve quality of patient care influenced or strongly influenced a decision by all groups to report an adverse outcome to a peer review process. Physician self-reporting is a more reliable method of identifying adverse outcomes than either medical chart review or incident reporting., Implications: Physician self-reporting is a more reliable method of identifying adverse outcomes than either medical chart review or incident reporting. Reporting by chart reviewers is biased both by the severity of outcome and severity of patient illness, whereas incident reports tend to focus on human error. All groups feel compelled to report adverse outcomes when the data may result in improved patient care.