The Cognitive Performance Test (CPT) is a standardized occupational therapy assessment that examines cognitive integration with functioning in an instrumental activities of daily living context. Conventional cognitive measures provide diagnostic utility but do not fully address the functional implications. Ninety-one veterans diagnosed with cognitive impairment were evaluated. We compared the predictive value of the CPT with the Large Allen Cognitive Level Screen (LACLS), Mini-Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA) for the need to retire from driving versus ability to pass an on-road exam. Measures were also analyzed by diagnostic classification. CPT correctly classified a mild versus major neurocognitive disorder, whereas MMSE, MoCA, and LACLS did not differentiate the groups. A CPT cutoff score of <4.7/5.6 showed 89% sensitivity for failing the road exam and 75% specificity for ability to pass. CPT discriminated functional level in neurocognitive disorders and had better predictive value for fitness to drive compared with conventional cognitive measures.