There is increasing emphasis on assessing multi-dimensional outcomes in traumatic brain injury (TBI), but achieving this aim is hampered by a plethora of overlapping assessment tools. There is a clear need for advice on the choice of outcomes and we examined level of functional recovery as a framework to guide selection of assessments. In this cohort study we analysed cross-sectional data from 2604 patients enrolled in the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) project. Patients were followed up 6 months after injury and assessed on the Glasgow Outcome Scale-Extended (GOSE), cognitive tests, and patient-reported outcomes. We describe assessment completeness and prevalence of impairment. Relationships between outcomes were visualized using UpSet plots and hierarchical cluster analysis. GOSE categories varied markedly for both completion rates, 34-91% for patient-reported outcomes and 9-81% for cognitive tests, and prevalence of impairment, 3-82% for patient-reported outcomes and 9-59% for cognitive tests. In complete case samples, the GOSE identified impairment in 59-61%, whereas the most impaired patient-reported outcome was the Short Form-12 version 2 (SF-12v2) Physical Component Summary (28% overall), and the most impaired cognitive test was Trail Making Test (TMT) Part A (19% overall). The findings show that degree of disability is a key context of use for cognitive tests and patient-reported outcomes. Level of functional recovery provides a guide to the feasibility of different types of assessment and the likelihood of impairment, and can help tailor suitable assessment approaches in clinical practice and research studies.