Comparison of the AIS-85 and AIS-90 with NASS-93

Two injury severity systems in widespread use by automobile manufacturers, motor vehicle accident investigators, researchers and trauma centers are the Abbreviated Injury Scale (AIS) and the National Accident Sampling System (NASS) Occupant Injury Classification [1][2][3]. Updates of these systems by AAAM (AIS-90) and NHTSA (NASS93), prevent data collected in differing versions of these systems from being accurately combined or trended without severity adjustments. This paper discusses and summarizes major differences between these coding systems, compares the number and percent distribution of injuries by severity, and reviews the need for methods to adjust severity.