&NA;A study to document the utilization by house officers of the Diagnostic Radiologic Examination (DRE) in trauma patients was carried out over 2 years at Stanford University Medical Center. Physicians recorded the likelihood of a fracture being present for patients requiring DRE's to evaluate traumatic injuries. The physician's opinion and the radiologist's final interpretation of the DRE were compared for 24 anatomic regions. Preliminary findings reveal: for almost half the DRE's the house officer indicated that the reason for the DRE was medicolegal; 7% of the medicolegal cases had fractures present; less than 4% of these fractures was important enough to change the medical treatment. The levels of house officer experience are suggested as possible causes of excessive DRE utilization, as well as the influence of defensive medicine. Using Green and Swets' Theory of Signal Detection, it is possible to mathematically describe an accuracy index, and a “fear” index for each physician. We plan to use this model in analysis of the study data.