BACKGROUND: Outcome measurement challenges rehabilitation services to select tools that promote stakeholder engagement in measuring complex interventions. OBJECTIVES: To examine the suitability of outcome measures for complex post-acute acquired brain injury (ABI) rehabilitation interventions, report outcomes of a holistic, neuropsychological ABI rehabilitation program and propose a simple way of visualizing complex outcomes. METHODS: Patient/carer reported outcome measures (PROMS), experience measures (PREMS) and staff-rated measures were collected for consecutive admissions over 1 year to an 18-week holistic, neuropsychological rehabilitation programme at baseline, 18 weeks and 3- and 6-month follow-up. RESULTS: Engagement with outcome measurement was poorest for carers and at follow-up for all stakeholders. Dependence, abilities, adjustment, unmet needs, symptomatology including executive dysfunction, and self-reassurance showed improvements at 18 weeks. Adjustment, social participation, perceived health, symptomatology including dysexecutive difficulties, and anxiety were worse at baseline for those who did not complete rehabilitation, than those who did. A radar plot facilitated outcome visualization. CONCLUSIONS: Engagement with outcome measurement was best when time and support were provided. Supplementing patient- with staff-rated and attendance measures may explain missing data and help quantify healthcare needs. The MPAI4, EBIQ and DEX-R appeared suitable measures to evaluate outcomes and distinguish those completing and not completing neuropsychological rehabilitation.