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Longitudinal factor structure of the WISC‐III among students with disabilities
Author(s) -
Watkins Marley W.,
Canivez Gary L.
Publication year - 2001
Publication title -
psychology in the schools
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 75
eISSN - 1520-6807
pISSN - 0033-3085
DOI - 10.1002/pits.1019
Subject(s) - psychology , developmental psychology , wechsler adult intelligence scale , longitudinal study , wechsler intelligence scale for children , test (biology) , metric (unit) , factor analysis , measurement invariance , intelligence quotient , factor (programming language) , statistics , cognition , confirmatory factor analysis , structural equation modeling , mathematics , paleontology , operations management , neuroscience , computer science , economics , biology , programming language
If the factor structure of a test does not hold over time (i.e., is not invariant), then longitudinal comparisons of standing on the test are not meaningful. In the case of the Wechsler Intelligence Scale for Children‐Third Edition (WISC‐III), it is crucial that it exhibit longitudinal factorial invariance because it is widely used in high‐stakes special education eligibility decisions. Accordingly, the present study analyzed the longitudinal factor structure of the WISC‐III for both configural and metric invariance with a group of 177 students with disabilities tested, on average, 2.8 years apart. Equivalent factor loadings, factor variances, and factor covariances across the retest interval provided evidence of configural and metric invariance. It was concluded that the WISC‐III was measuring the same constructs with equal fidelity across time which allows unequivocal interpretation of score differences as reflecting changes in underlying latent constructs rather than variations in the measurement operation itself. © 2001 John Wiley & Sons, Inc.