The general ability measure for adults underrepresents true IQ in a high-functioning aviation population

Abstract

The General Ability Measure for Adults (GAMA) is a brief nonverbal assessment of general intellectual ability. Presently, there is a lack of research involving the use of the GAMA in a high-functioning population. Aviation pilots (n = 59) were referred for a neuropsychological evaluation and were concluded to be cognitively intact. They were administered a battery that included the GAMA and Wechsler Adult Intelligence Scale – 4th edition (WAIS-IV). A paired samples t-test revealed that IQ scores on the GAMA were significantly lower than IQ scores on the WAIS-IV, with WAIS-IV IQ being 7.54 points higher on average. Fisher’s exact test determined there was significant disagreement in score classification between the tests, with individuals classified as Above Average on the WAIS-IV often being classified as Average on the GAMA. The GAMA appears to significantly underrepresent true IQ in both score and classification when compared to a more robust measure of intellectual assessment. Clinically, this suggests that IQ screeners, such as the GAMA, may not be appropriate for assessing patients who are suspected to be of higher premorbid functioning. Future research should expand on these results to assess the validity of verbal-based IQ screening measures in high-functioning populations.