1) Assessment of effort is important in TBI clinical practice and research to generate valid data on patients' true cognitive capacities, as poor effort is common and can invalidate test results. 2) Formal effort tests should be integrated into evaluations to detect exaggeration and rule out other factors, given the effects of poor effort can dwarf those of mild TBI. 3) Various external incentives like compensation can adversely impact effort, so it is important to consider effort and response bias in clinical and research work involving people with TBI.