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Incremental validity of WISC – IV UK factor index scores with a referred I rish sample: Predicting performance on the WIAT – II UK
Author(s) -
Canivez Gary L.,
Watkins Marley W.,
James Trevor,
Good Rebecca,
James Kate
Publication year - 2014
Publication title -
british journal of educational psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.557
H-Index - 95
eISSN - 2044-8279
pISSN - 0007-0998
DOI - 10.1111/bjep.12056
Subject(s) - wechsler adult intelligence scale , wechsler intelligence scale for children , psychology , intelligence quotient , achievement test , developmental psychology , statistics , standardized test , cognition , psychiatry , mathematics , mathematics education
Background Subtest and factor scores have typically provided little incremental predictive validity beyond the omnibus IQ score. Aims This study examined the incremental validity of Wechsler Intelligence Scale for Children – Fourth UK Edition ( WISC – IV UK ; Wechsler, 2004a, Wechsler Intelligence Scale for Children – Fourth UK Edition , Harcourt Assessment, London, UK) and factor index scores in predicting academic achievement on the Wechsler Individual Achievement Test – Second UK Edition ( WIAT – II UK ; Wechsler, 2005a, Wechsler Individual Achievement Test‐Second UK Edition , Pearson, London, UK), beyond that predicted by the WISC – IV UK FSIQ . Sample The sample included 1,014 Irish children (ages 6–0 to 16–9) who were referred for evaluation of learning difficulties. Method Hierarchical multiple regression analyses were used with the WISC – IV UK FSIQ (Block 1) and factor index scores (Block 2) as predictors and WIAT – II UK subtest and composite scores as dependent variables. Results The WISC – IV UK FSIQ accounted for statistically significant and generally large portions of WIAT – II UK subtest and composite score variance. WISC – IV UK factor index scores combined to provide statistically significant increments in prediction of most WIAT – II UK subtest and composite scores over and above the FSIQ ; however, the effect sizes were mostly small as previously observed (i.e., Canivez, 2013a, Psychol. Assess ., 25 , 484; Glutting et al ., 2006, J. Spec. Educ ., 40 , 103; Nelson et al ., 2013, Psychol. Assess ., 25 , 618). Individually, the WISC – IV UK factor index scores provided small unique contributions to predicting WIAT – II UK scores. Conclusion This, in combination with studies of apportioned variance from bifactor confirmatory factor analysis (Watkins et al ., 2013, Int. J. Sch. Educ. Psychol ., 1 , 102), indicated that the WISC – IV UK FSIQ should retain the greatest weight in WISC – IV UK interpretation.