Measurement Invariance of the Wechsler Intelligence Scale for Children, Fifth Edition 10-Subtest Primary Battery: Can Index Scores be Compared across Age, Sex, and Diagnostic Groups?

Measurement invariance of the Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V) 10 subtest primary battery was evaluated across sex, age (6–8, 9–11, 12–14, and 15–16 year-olds), and three diagnostic (attention-deficit/hyperactivity disorder, anxiety, and encephalopathy) groups within a large clinical sample (N = 5359) referred to a children’s specialty hospital. Competing models were tested using confirmatory factor analysis (CFA), and a five-factor oblique model corresponding to the publisher’s hypothesized first-order measurement model (e.g., verbal comprehension, fluid reasoning, visual-spatial, working memory, and processing speed) was found to have the best model fit. Multigroup CFA was subsequently used to evaluate progressively more restrictive constraints on the measurement model. Results indicated that full metric invariance was attained across the three groups studied. Full scalar invariance was attained for sex and diagnostic groups. Partial scalar invariance was attained for age-group. The results of this study provide support for the first-order scoring structure of the five WISC-V factors in the 10 subtest primary battery with this large clinical sample.