Confirmatory factor analysis of the WIAT‐III in a referral sample

Abstract

AbstractThe Wechsler individual achievement test, third edition (WIAT‐III) is a popular individually administered achievement battery. Despite its ubiquity in assessment practice, scant research into its structure exists. We analyzed the structure of the WIAT‐III in a sample of students in Grades 3–12 referred for special education evaluations (n = 355). Using confirmatory factor analysis, we evaluated the fit of the factor structure assumed by the composite scores provided by the test publisher. We then compared that model to alternative first‐order, second‐order and bifactor models in an exploratory fashion. Results demonstrated that the publisher implied model does not capture the structure of the WIAT‐III. Instead subtests appear related to each other based on both their domain of academic performance and in other shared abilities. Implications for practice are discussed.