This self-directed learning module highlights several aspects of outcome after acquired brain injury rehabilitation. It is part of the chapter on brain injury rehabilitation in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. In this article, functional measures commonly used in rehabilitation are described, and their potential uses for various populations are discussed. Key physiologic factors that predict outcome for persons with different acquired brain injuries are identified. Variables that affect return to school and work are described, and the studies evaluating the effectiveness of brain injury rehabilitation programs in general, as well as their subcomponents, are also reviewed.(a) To describe variables that affect outcome after acquired brain injury and (b) to identify the outcome tools most appropriate for the patient populations and outcomes to be studied.