Hippocrates is said to have remarked in 400 BC that “No head injury is too severe to despair of, nor too trivial to ignore.” While this prognostic scheme achieves absolute accuracy, its precision leaves something to be desired. More recently, many groups have attempted to produce more detailed risk adjustment models for predicting outcome in traumatic brain injury. In 2006, a systematic review concluded that most predictive models were inadequately validated, poorly presented, and based on studies from single centres with small samples that excluded patients from low income countries (where traumatic brain injury is most common).1 In the accompanying paper, the Medical Research Council CRASH Trial Collaborators provide a series of prognostic models that attempt to remedy these shortcomings.2

Their models were developed on clinical data from the 10 008 patients recruited to a trial of corticosteroids in traumatic brain injury.3 4 Separate variants of the models allow the option of including imaging data from computed tomography, and of selecting data …