 Research Design: Methodologies for this study include both prospective and retrospective approaches. Experts will convene in Tampa to operationalize a gold standard for TBI identification Objective 1. Retrospective, population-based cohort analyses of extant databases will provide insight into current practices and findings to address Objective 2. The gold standard developed in Objective1 will be implemented with a small time-limited prospective cohort so that psychometric analysis of the TBI screen can be conducted Objective 3. Findings from these analyses will help identify potential improvement in the TBI Screening process to address Objective 4. 