1) Evaluate the value and strength of a competency framework for identifying and measuring performance requirements for expeditionary surgeons; 2) Verify psychometric integrity of assessment instrumentation for measuring domain knowledge and skills; 3) Identify gaps in knowledge and skills capabilities using assessment strategies; 4) Examine shared variance between knowledge and skills outcomes, and the volume and diversity of routine surgical practice. Expeditionary military surgeons provide care for patients with injuries that extend beyond the care requirements of their routine surgical practice. The readiness of these surgeons to independently provide accurate care in expeditionary contexts is important for casualty care in military and civilian situations. Identifying and closing performance gap areas are essential for assuring readiness. We implemented evidence-based processes for identifying and measuring the essential performance competencies for expeditionary surgeons. All assessment instrumentation was rigorously examined for psychometric integrity. Performance outcomes were directly measured for expeditionary surgical knowledge and skills and gap areas were identified. Knowledge and skills assessment outcomes were compared, and also compared to the volume and diversity of routine surgical practice to determine shared variance. Outcomes confirmed the integrity of assessment instrumentation and identified significant performance gaps for knowledge and skills in the domain. Identification of domain competencies and performance benchmarks, combined with best-practices in assessment instrumentation, provided a rigorous and defensible framework for quantifying domain competencies. By identifying and implementing strategies for closing performance gap areas, we provide a positive process for assuring surgical competency and clinical readiness.