Comparison of the factor structure of the Reynolds Intellectual Assessment Scales (RIAS) in a typically-developing and mixed clinical group of Canadian children




Irwin, Julie K.

Journal Title

Journal ISSN

Volume Title



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.



Reynolds Intellectual Assessment Scales, RIAS, Validity, psychometric properties, children, Canadian, factor structure, WISC-IV, clinical