IQ Scores Should Be Corrected for the Flynn Effect in High-Stakes Decisions

Abstract

IQ test scores should be corrected for high stakes decisions that employ these assessments, including capital offense cases. If scores are not corrected, then diagnostic standards must change with each generation. Arguments against corrections, based on standards of practice, information present and absent in test manuals, and related issues, ignore expert consensus about the assessment of intellectual disabilities and the acceptance of the Flynn effect in the field. Most psychometric concerns about correction are based on validity studies with small subgroups and do not reflect sufficient effort to estimate the precision of the Flynn estimate. We computed a confidence interval for the Wechsler PIQ across four validity studies that shows a SEM of about 1 around a mean of about 3 points per decade. A meta-analytic weighted mean of the 14 studies in Flynn (2009) is 2.80 (2.50, 3.09), close to Flynn’s (2009) unweighted average (2.99). More psychometric research would be helpful, but this level of precision supports the Flynn adjustment of 3 points per decade.

Keywords

IQ intellectual disability Flynn effect Atkins hearings

Get full access to this article

View all access options for this article.

References

Flynn, J.R. ( 2009). The WAIS-III and WAIS-IV: Daubert motions favor the certainly false over the approximately true. Applied Neuropsychology , 16, 98-104.

Flynn, J.R. ( 2010). Problems with IQ gains: The huge vocabulary gap. Journal of Psychoeducational Assessment, 28, 412-433.

Gresham, F.M. ( 2009). Interpretation of intelligence test scores in Atkins cases: Conceptual and psychometric issues. Applied Neuropsychology , 16, 91-97.

Hagan, L.D. , Drogin, E.Y. , & Guilmette, T.J. (2008). Adjusting IQ scores for the Flynn effect: Consistent with standard of practice? Professional Psychology: Research and Practice, 39, 619-625.

Hagan, L.D. , Drogin, E.Y. , & Guilmette, T.J. (2010). IQ scores should not be adjusted for the Flynn effect in capital punishment cases. Journal of Psychoeducational Assessment, 28, 474-476.

Kanaya, T. , & Ceci, S.J. ( 2007). Mental retardation diagnosis and the Flynn effect: General intelligence, adaptive behavior, and context. Child Development Perspectives, 1, 62-63.

Kaufman, A.S. ( 2010). "In what way are apples and oranges alike?": A critique of Flynn’s interpretation of the Flynn effect. Journal of Psychoeducational Assessment, 28, 382-398.

Lipsey, M.W. , & Wilson, D.B. ( 2001). Practical meta-analysis. Thousand Oaks, CA: Sage.

Schalock, R. , Borthwick-Duffy, S. , Bradley, V. , Buntinx, W. , Coulter, D. , Craig, E. , . . . Yeager, M. ( 2010). Intellectual disability: Definition, classification, and systems of support (11th ed.). Washington, DC: American Association on Intellectual and Developmental Disabilities.

10.

Weiss, L.G. ( 2008). WAIS-III technical report: Response to Flynn. Retrieved from http://www.pearsonassessments.com/NR/rdonlyres/98BBF5D2-F0E8-4DF6-87E2-51D0CD6EE98C/0/WAISIII_TR_lr.pdf

11.

Widaman, K. ( 2007). Stalking the roving IQ score cutoff: A commentary on Kanaya and Ceci. Child Development Perspectives, 1, 57-59.

12.

Zhou, X. , Zhu, J. , & Weiss, L. G. (2010). Peeking inside the "black box" of the Flynn effect: Evidence from three Wechsler instruments. Journal of Psychoeducational Assessment, 28, 399-411.

13.

Zhu, J. , & Tulsky, D.S. ( 1999). Can IQ gain be accurately quantified by a simple difference formula? Perceptual and Motor Skills, 88, 1255-1260.