Characterization of injury severity is crucial to the scientific study of trauma, yet the actual measurement of injury severity began only 50 years ago. In 1969, researchers developed the Abbreviated Injury Scale (AIS) to grade the severity of individual injuries. Since its introduction, by the Association for the Advancement of Automotive Medicine (AAAM) International Injury Scaling Committee (IISC), the parent organization of the AIS modified the AIS, most recently in 2005 (AIS-2005). The AIS is the basis for the Injury Severity Score (ISS), which is the most widely used measure of injury severity in patients with trauma. Attempting to summarize the severity of injury in a patient with multiple traumas with a single number is difficult at best; therefore, multiple alternative scoring systems have been proposed, each with its own problems and limitations.
This article reviews the conceptual and statistical background necessary to understand injury severity scoring, presents the most common scoring systems, and addresses new ideas and trends in trauma scoring.