A consensus-validation study used action research methods to identify relevant nursing diagnoses, nursing interventions, and patient outcomes for a population of adults with traumatic brain injury (TBI) in long-term care. In meetings totaling 159 hours to reach 100% consensus through group discussions, the three classifications of NANDA International's (NANDA-I's) approved nursing diagnoses, the Nursing Interventions Classification (NIC), and the Nursing Outcomes Classification (NOC) were used as the basis for three nurses experienced in working with adults with TBI to select the elements of nursing care. Among almost 200 NANDA-I nursing diagnoses, 29 were identified as relevant for comprehensive nursing care of this population. Each nursing diagnosis was associated with 3–11 of the more than 500 NIC interventions and 1–13 of more than 300 NOC outcomes. The nurses became aware of the complexity and the need for critical thinking. The findings were used to refine the facility's nursing standards of care, which were to be combined with the interdisciplinary plan of care and included in future electronic health records.