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. / Graduate

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This study presented the past, current, and proposed practice of intelligence testing with a unique population, students identified as deaf and hard of hearing (D/HH). As a basis for describing the cognitive ability of Utah's D/HH students and to improve practice guidelines, 61 D/HH students served by Utah Schools for the Deaf and the Blind (USDB) were administered the Universal Nonverbal Intelligence Test (UNIT) standard battery and the Perceptual Reasoning Index (PRI) subtests from the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV). Based on these data, composite score distributions were described and compared with national standardization samples. Participants' WISC-IV PRI scores are summarized with the following descriptive statistics: M = 88.95, 11.05 points below the standardization sample's mean; SD = 14.55; skew = -.74; and SE = .31. Comparing the USDB D/HH sample's WISC-IV PRI scores with the WISC-IV standardization sample's distribution of scores, the participants' scores were significantly lower (two-tailed p-value of <.0001). Participants' UNIT Standard Battery Composite scores are summarized with the following descriptive statistics: M = 90.74, 9.26 points less than the standardization sample's mean; SD = 13.97; skew = -.55; and SE = .31. Comparing this sample's UNIT composite scores with the standardization sample, the participants' scores were significantly lower (two-tailed p-value of <.0001). Additionally, a Pearson correlation compared each participant's scores on the WISC-IV PRI with the corresponding score on the UNIT Standard Battery Composite, yielding a correlation coefficient of .75 with a two-tailed p-value < .0001. Recommendations for future guidelines regarding cognitive assessment of Utah's D/HH students are presented. In particular, this research supported administering the UNIT rather than the WISC-IV. Though no assessment is language free, the UNIT's administration uses simple gestures for directions, rather than spoken language. Additionally, D/HH students were included in the standardization sample. Furthermore, administering one assessment, rather than several, consumes less time for the examiner and the student, saving money and decreasing student time away from classroom instruction.