Construct Validity of the Wechsler Intelligence Scale for Children -- Fifth UK Edition: Exploratory and Confirmatory Factor Analyses of the 16 Primary and Secondary Subtests

Background: There is inadequate information regarding the factor structure of the Wechsler Intelligence Scale for Children -- Fifth UK Edition (WISC-V[superscript UK]; Wechsler, 2016a, Wechsler Intelligence Scale for Children-Fifth UK Edition, Harcourt Assessment, London, UK) to guide interpretation. Aims and methods: The WISC-V[superscript UK] was examined using complementary exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) for all models proposed by Wechsler (2016b, Wechsler Intelligence Scale for Children-Fifth UK Edition--Administration and scoring manual, Harcourt Assessment, London, UK) as well as rival bifactor models. Sample: The WISC-V[superscript UK] standardization sample (N = 415) correlation matrix was used in analyses due to denial of standardization sample raw data. Results: EFA did not support a theoretically posited fifth factor because only one subtest (Matrix Reasoning) had a salient pattern coefficient on the fifth factor. A model with four group factors and a general intelligence factor resembling the Wechsler Intelligence Scale for Children -- Fourth Edition (WISC-IV; Wechsler, 2003, Wechsler Intelligence Scale for Children-Fourth Edition, Psychological Corporation, San Antonio, TX, USA) was supported by both EFA and CFA. General intelligence (g) was the dominant source of subtest variance and large omega-hierarchical coefficients supported interpretation of the Full Scale IQ (FSIQ) score. In contrast, the four group factors accounted for small portions of subtest variance and low omega-hierarchical subscale coefficients indicated that the four-factor index scores were of questionable interpretive value independent of g. Present results replicated independent assessments of the Canadian, Spanish, French, and US versions of the WISC-V (Canivez, Watkins, & Dombrowski, 2016, "Psychological Assessment," 28, 975; 2017, "Psychological Assessment," 29, 458; Fennollar-Cortés & Watkins, 2018, "International Journal of School & Educational Psychology"; Lecerf & Canivez, 2018, "Psychological Assessment"; Watkins, Dombrowski, & Canivez, 2018, "International Journal of School and Educational Psychology"). Conclusion: Primary interpretation of the WISC-VUK should be of the FSIQ as an estimate of general intelligence.