Reliability and factorial validity of the Canadian Wechsler Intelligence Scale for Children–Fifth Edition

ABSTRACT

The reliability and factorial validity of the Wechsler Intelligence Scale for Children–Fifth Edition: Canadian (WISC-V^CDN) was investigated. The higher-order model preferred by Wechsler (2014b) contained five group factors but lacked discriminant validity. An alternative bifactor model with four group factors and one general factor, akin to the traditional Wechsler model, exhibited the best global fit. The general factor accounted for 33.8% of the total variance and 67.6% of the common variance, but none of the group factors accounted for substantial portions of variance. All together, the general and group factors accounted for 50% of the total variance. Omega reliability coefficients demonstrated that reliable variance of WISC-V^CDN factor index scores was primarily due to the general factor, not the group factors. It was concluded that the cumulative weight of reliability and validity evidence suggests that psychologists should focus their interpretive efforts at the general factor level and exercise extreme caution when using group factor scores to make decisions about individuals.

KEYWORDS:

• WISC-V
• CFA
• bifactor
• intelligence
• validity
• reliability

Additional information

Notes on contributors

Marley W. Watkins

Marley W. Watkins, PhD, is a Non-Resident Scholar in the Department of Educational Psychology at Baylor University. His research interests include professional issues, the psychometrics of assessment and diagnosis, and individual differences.

Stefan C. Dombrowski

Stefan C. Dombrowski, is Professor and Director of the School Psychology Program at Rider University. His research has focused on such topics as structural validity, prenatal exposures, children’s mental health, and psychoeducational assessment.

Gary L. Canivez

Gary L. Canivez, PhD, is Professor of Psychology at Eastern Illinois University. His research interests include psychometric reliability and validity investigations of measures of intelligence, achievement, psychopathology, and test bias.