The use of Abbreviated Injury Scaling for the Head region (HAIS) was evaluated as a prognostic index of functional outcome in 503 consecutive patients with severe injury to the brain who survived initial resuscitation. Although a strong statistical relationship between HAIS and outcome as measured by the Glasgow Outcome Scale was demonstrated, its clinical usefulness is limited. HAIS may be most useful as a classifier for comparative studies of populations and for the evaluation of therapeutic modalities.