Comparison of the factor structure of the Reynolds Intellectual Assessment Scales (RIAS) in a typically-developing and mixed clinical group of Canadian children
Date
2011-11-22
Authors
Irwin, Julie K.
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Abstract
Objective. This thesis examines the extent to which an intelligence test, the Reynolds Intellectual Assessment Scales (RIAS), aligned with the Carroll-Horn-Cattell theory of intelligence in children ages 4-18 who are either typically-developing or who have a variety of clinical impairments. Other aspects of the RIAS’s construct validity were also evaluated, including its relationship with the Wechsler Intelligence Scales for Children – Fourth Edition (WISC-IV) and whether the RIAS measures intelligence in the same way in typically-developing children as in children with traumatic brain injury (TBI).
Methods. Confirmatory factor analysis was used to evaluate the fit of one-factor (g) and two-factor (Verbal Ability and Non-Verbal ability) models in each sample. Configural and measurement invariance of each model were evaluated across the typically-developing group and a group of children with TBI. Correlations between scores on the RIAS and WISC-IV were examined in a group of children with clinical disorders.
Results. The two-factor model fit the data of both groups while the one-factor model provided good fit to only the typically-developing group`s data. Both models showed configural invariance across groups, measurement invariance of the two-factor model, and partial measurement invariance of the one-factor model (What`s Missing subtest unconstrained), but scalar invariance was not established for either model. RIAS’s verbal subtests and indexes correlated with theoretically consistent WISC-IV indexes but the RIAS’s nonverbal subtests and indexes did not correlate highly with WISC-IV performance subtests. All RIAS index scores were higher than WISC-IV index scores.
Conclusions. Evidence for the interpretability of the NIX and VIX as separate indexes was not found. The VIX is a valid index of crystallized abilities but the NIX does not adequately measure fluid intelligence. The CIX appears to provide a valid measure of g, but may be overly reliant on verbal abilities. The RIAS has significant validity issues that should limit its use in making important decisions.
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Keywords
Reynolds Intellectual Assessment Scales, RIAS, Validity, psychometric properties, children, Canadian, factor structure, WISC-IV, clinical