Intelligent Use of Intelligence Tests

Abstract

It is well established that Canadians produce higher raw scores than their U.S. counterparts on intellectual assessments. As a result of these differences in ability along with smaller variability in the population's intellectual performance, Canadian normative data will yield lower standard scores for most raw score points compared to U.S. norms. Two recent studies have questioned the utility of the WAIS-IV Canadian norms based on the performance of a mixed clinical sample of post-secondary students. These studies suggest that a greater proportion of cases from their mixed clinical samples fall below a full-scale IQ of 85 using the WAIS-IV Canadian norms than should be "expected." The purpose of the current study is threefold: First, to summarize the consistent finding of Canada-U.S. differences on measures of ability and present new empirical analyses to demonstrate these results are not due to a smaller sample size for Canadian norms. Second, and most importantly, matched sample comparisons demonstrate that the proportion of low scoring individuals (FSIQ < 85) in mixed clinical samples is consistent with the rates published by recent studies, and not greater than expected. Third, we offer evidence-based advice to clinicians practicing in Canada on the appropriate use of Canadian norms for Canadian clients during an individual assessment of intellectual functioning.

Getting Back to the Main Point

“…While we agree with Miller et al (2015) that such diagnostic decisions should be based on more than just one IQ score on one day, the fact remains that IQ scores are still "routinely used to differentially classify mental disability" (McDermott, Watkins, & Rhoad, 2014, p. 207) and students in school boards across Ontario, Canada, are often assigned an exceptionality classification of "Mild Intellectual Disability (MID)" on the basis of IQ test scores alone (Harrison & Holmes, 2014). Furthermore, the College Council on Disability Issues (2009) and Ford (2014) stated that community colleges in Ontario have agreed that students identified as MID (a FSIQ between 71 and 78) or those with "borderline intellectual functioning" (FSIQ between 71 and 84) would qualify for academic accommodations and government-provided disability funding support of to up to $10,000 a year (c.f.…”

“…Again, our data indicate that different percentages of individuals would qualify in these categories based on choice of norms. Miller et al (2015) suggest that our findings were due to both the nature of our clinical sample and also possible symptom exaggeration. These arguments, however, miss the point.…”

“…Getting Back to the Main Point Miller et al (2015) discuss many issues in their article, but do not address the primary tenet of our two studies (Harrison, Armstrong, Harrison, Lange, & Iverson, 2014;Harrison, Holmes, Silvestri, & Armstrong, 2015). It was not our intention to imply that the Canadian norms have no utility.…”

Test Review: Wechsler Intelligence Scale for Children, Fifth Edition: Canadian 322 (WISC-VCDN) by D. Wechsler

“…Developing Canadian norms for the WISC-V CDN reflects an established need for obtaining a norming sample that accounts for differences between Canadians and Americans (Beal, Dumont, Cruse, & Branche, 1996;Iverson, Lange, & Viljoen, 2006;Miller et al, 2015). Two primary reasons for this need is the recurrent findings that Canadian children score higher than American children in most domains that measure ability (Bowden, Saklofske, & Weiss, 2011b) and that some test items appear to be inappropriate for Canadians (Wechsler, 2014).…”

Hierarchical Structure of the Wechsler Adult Intelligence Scale–Fourth Edition with an Egyptian Sample

“…However, Canivez and Kush (2013) questioned the results of Weiss et al (2013b) on the grounds of theoretical, methodological, and practical problems. Furthermore, some studies compared the differences in WAIS-IV Canadian and U.S. norms (Harrison, Holmes, Silvestri, & Armstrong, 2015a, 2015b; J. L. Miller et al, 2015).…”