Dean, A. C., Victor, T. L., Boone, K. B., & Arnold, G. (2008). The relationship of IQ to effort test performance. The Clinical Neuropsychologist, 22(4), 705-722.
The relationship between IQ and nine effort indicators was examined in a sample of 189 neuropsychology clinic outpatients who were not in litigation or attempting to obtain disability. Participants with the lowest IQ (50-59) failed approximately 60% of the effort tests, while patients with an IQ of 60 to 69 failed 44% of effort indicators, and individuals with borderline IQ (70 to 79) exhibited a 17% failure rate. All patients with IQ < 70 failed at least one effort test. Cutoffs for the Warrington Recognition Memory Test (Words) and Finger Tapping maintained the highest specificities in low IQ samples. (PsycINFO Database Record (c) 2009 APA, all rights reserved)