Green, P., Rohling, M. L., Lees-Haley, P. R., & Allen, L. M., III. (2001). Effort has a greater effect on test scores than severe brain injury in compensation claimants. Brain Injury, 15(12), 1045-1060.

904 consecutive patients, including 80 neurological patients (mean age 46.5 yrs) and 470 with head injuries (mean age 39.0 yrs), were given neuropsychological tests. All 43 test scores were converted to normative Z-scores and averaged, giving an Overall Test Battery Mean (OTBM). A variable measuring effort correlated 0.73 with the OTBM. The OTBM mean score was 1.20 standard deviations lower in those who failed the Word Memory Test (WMT) than in those who passed the WMT. Sub-optimal effort suppressed the OTBM 4.5 times more than did moderate-severe brain injury. When only those making a good effort were included, patients with severe brain injuries and neurological diseases scored significantly lower than groups presumed to have no neurological impairment, but these group differences were not seen when all cases were analyzed together. These data illustrate the importance of measuring and controlling for sub-optimal effort in individual neuropsychological evaluations, as well as in empirical research with similar groups of patients. (PsycINFO Database Record (c) 2002 APA, all rights reserved)

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