Methodological considerations in the use of the abbreviated injury scale in trauma epidemiology

As part of an incidence study of external cause-specific trauma, the Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS) are being used to measure the severity of the anatomic injuries. Problems identified in the study pilot phase by medical record specialists, after training in AIS procedures, include noteworthy variations in the interpretation of scaling procedures in the AIS dictionary. The AIS dictionary was replaced by a newly designed single page (SP) precoded abstracting form. It contains alphabetical descriptors for each trauma type within a body region and a unique 3-digit identifier assigned to each. The AIS severity codes are not mentioned on the form. Abstractors are instructed to code all injuries for an episode. A computer algorithm has been developed and implemented to assign the AIS severity codes. Accuracy and precision improved markedly by eliminating the need to make severity scoring decisions during the AIS coding process.