The purpose of the TBI-Prognosis study is to develop a prognostic model and clinical prediction rule by using a multimodal approach of different prognostic indicators and their evolution over time in the acute phase of care. This study, taking place in 17 Canadian trauma centers, will improve our ability to prognosticate and identify patients who will benefit from aggressive care in the acute phase, and help preventing erroneous evaluation of prognosis that could have lethal consequences when used to decide to pursue or withdraw life-sustaining therapies.