Our recent improved understanding of traumatic brain injury (TBI) comes largely from cohort studies of TBI patients with indication for computed tomography (CT). Using CT head as an inclusion criterion may overestimate poor outcomes after TBI with Glasgow Coma Scale (GCS) 13-15. We aimed to compare outcomes after TBI in adults who had a head CT scan (with negative findings) versus those who had no CT when presenting to an emergency department. This was a secondary analysis of a trial that recruited adults with GCS = 13-15 after TBI in Vancouver, Canada. We included 493 participants (18-69 years, 54% female), after removing