Objective: --To identify potentially preventable sources of medical injury in obstetrics and gynecology, general surgery, anesthesiology, and radiology.Design: --Retrospective review of physician malpractice claim records.Setting: --Large New Jersey physician malpractice insurer.Participants: --Physicians practicing obstetrics and gynecology, general surgery, anesthesiology, and radiology and covered by the insurance carrier during any portion of 1977 through 1989.Main Outcome Measures: --Proportion of claims due to negligence associated with errors in (1) patient management, (2) technical performance, and (3) medical and nursing staff coordination and the clinical and financial consequences of such errors.Results: --Among 1371 claims ascribed to negligence, patient management errors were cited most frequently in all four specialties (48% to 75%) and, compared with performance and coordination problems, were generally associated with a higher frequency of serious injury and higher median payments. Coordination problems accounted for about 9% of claims. In obstetrics and gynecology, newborn delivery claims usually arose from management errors (57% to 68%), whereas gynecologic procedure claims were most often associated with performance errors (55% to 73%). Underperformance of cesarean section was cited more frequently than overperformance (31% vs 3%). General surgery claims were about equally divided between management and performance types regardless of procedure. Failure to perform appropriate diagnostic testing or monitoring was the main problem in 3% to 8% of claims.Conclusion: --Malpractice data can be used to identify problem-prone clinical processes and suggest interventions that may reduce negligence. [ABSTRACT FROM AUTHOR]