We have previously described high rates of executive function impairment in clients referred by Adult Protective Services (APS) to geriatric psychiatry for decision-making capacity assessments. The purpose of this study was to determine the independent relationship between neuropsychological screening instruments, particularly instruments sensitive to executive function, and performance-based functional tasks in elder referrals. Our retrospective medical review (n = 75/157 referrals completed all neuropsychological and functional assessments) revealed that only the Executive Interview (EXIT25) contributed independent variance to money management performance (R(2) = 0.29, p < 0.001), telephone use ability (R(2) = 0.39, p < 0.001), and summed performance (R(2) = 0.45, p < 0.001). Executive instruments may specifically inform decision-making capacity assessments.