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Common IQ Methodology May be Flawed

Common IQ Methodology May Be Flawed

A Canadian researcher has discovered inconsistencies in the widely used Wechsler Adult Intelligence test (WAIS-IV).

Queen’s University professor Dr. Allyson Harrison and her colleagues examined the differences between Canadian and American WAIS-IV scores from 861 postsecondary students from across Ontario.

The research identified a trend where the individual’s scores were consistently lower using the Canadian test scoring system.

The discrepancy is alarming as the WAIS-IV is one of the most widely used intelligence tests in the world.

IQ scores are used to predict educational success, to help identify intellectual disabilities or intellectual giftedness, and to establish whether a person has a specific learning disability.

For her research, Harrison and colleagues examined the differences between Canadian and American WAIS-IV scores from 861 postsecondary students from across Ontario.

The WAIS-IV scores are used to make diagnostic decisions on the person’s ability relative to their peer group.

“Looking at the normal distribution of scores, you’d expect that only about five percent of the population should get an IQ score of 75 or less,” says Dr. Harrison.

“However, while this was true when we scored their tests using the American norms, our findings showed that 21 percent of college and university students in our sample had an IQ score this low when Canadian norms were used for scoring.”

The trend was the same across all IQ scores, with Canadian young adults in college or university consistently receiving a lower IQ score if the Canadian norms were used.

There were fewer gifted students identified when Canadian norms were used, as well as more students who were said to be intellectually impaired.

When scoring the WAIS-IV, Canadian psychologists have the option to compare the obtained raw score with the normative data gathered in either Canada or the U.S.

Harrison noted these findings have serious implications for educational and neuropsychological testing.

“Research shows that you can go from being classified as average to intellectually impaired based only on whether American or Canadian norms are used to rank the obtained raw IQ score.”

Source: Queen’s University/EurekAlert

Common IQ Methodology May Be Flawed

Rick Nauert PhD

Rick Nauert, PhDDr. Rick Nauert has over 25 years experience in clinical, administrative and academic healthcare. He is currently an associate professor for Rocky Mountain University of Health Professionals doctoral program in health promotion and wellness. Dr. Nauert began his career as a clinical physical therapist and served as a regional manager for a publicly traded multidisciplinary rehabilitation agency for 12 years. He has masters degrees in health-fitness management and healthcare administration and a doctoral degree from The University of Texas at Austin focused on health care informatics, health administration, health education and health policy. His research efforts included the area of telehealth with a specialty in disease management.

APA Reference
Nauert PhD, R. (2018). Common IQ Methodology May Be Flawed. Psych Central. Retrieved on November 24, 2020, from
Scientifically Reviewed
Last updated: 8 Aug 2018 (Originally: 18 Mar 2015)
Last reviewed: By a member of our scientific advisory board on 8 Aug 2018
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