Objective: The purpose of this study was to compare the interpretive effects of applying American versus Canadian normative systems for younger children using the Wechsler Intelligence Scale for Children (WISC-IV). Method: A large sample (N = 300) of children in grade 7 were administered the WISC-IV as part of a learning disability evaluation. All protocols were scored using both the Canadian and American normative data. Results: Statistically significant differences were found between the obtained IQ, Index and subtests scores when the Canadian as opposed to the American normative systems were applied. The effect sizes of the differences, however, were small to medium. The average FSIQ using the American norms was 93.8 (SD = 10.6) compared to 90.2 (SD = 10.3) using the Canadian norms. The largest difference in index scores was found in the Working Memory Index score (Cohen's d = .33). For individual subtests, the largest differences were on Letter Number Sequencing (d = .38), and Comprehension (d = .35). The smallest differences were on Coding (d= -.04), Picture Completion (d = −.04), and Matrix Reasoning (d = −.08). Percentage agreement in normative classifications, defined as American and Canadian index scores within 5 points or within the same classification range, was as follows: FSIQ = 81.5%, GAI = 88.6%, VCI = 81.6%, PRI = 94.6%, WMI = 79.6%, and PSI = 97.7%. Conclusion: Contrary to recent findings regarding the WAIS-IV, the Canadian norms for the WISC-IV do not systematically reduce scores relative to American-derived scores. While significant differences were found, the effects were small and rarely meaningful. Only 1/5 of Canadian children with specific learning disabilities and/or ADHD obtained FSIQ or GAI scores that changed classification when accounting for measurement error.
PROFESSIONAL ISSUES: TEST DEVELOPMENT AND METHODS
Comparing Canadian and American Normative Scores on the Wechsler Intelligence Scale for Children-Fourth Edition
A Harrison, I Armstrong; PROFESSIONAL ISSUES: TEST DEVELOPMENT AND METHODS
Comparing Canadian and American Normative Scores on the Wechsler Intelligence Scale for Children-Fourth Edition. Arch Clin Neuropsychol 2015; 30 (6): 561. doi: 10.1093/arclin/acv047.197
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