The fourth edition of the Wechsler Adult Intelligence Scale (WAIS-IV) is a revised and substantially updated version of its predecessor. The purposes of this research were to determine the constructs measured by the test and the consistency of measurement across large normative and clinical samples. Competing higher order WAIS-IV four- and five-factor models were analyzed using the WAIS-IV’s sample of 1,800 normative adults and 411 clinical adults. When all 15 WAIS-IV subtests were considered, both four- and five-factor models were suitable, but the five-factor model provided a better fit. The WAIS-IV PRI differentiated into two composites as follows: POI(Gv) consisting of Block Design, Visual Puzzles and Picture Completion; and FRI(Gf) consisting Matrix Reasoning, Arithmetic and Figure Weights. The five-factor solution included Quantitative Reasoning (RQ), consisting of Arithmetic and Figure Weights, as a narrow ability subsumed under FRI(Gf). Arithmetic, Vocabulary, and Figure Weights subtests had the highest g loadings. Cancellation had the lowest g loading. The WAIS-IV generally demonstrated full factor invariance between clinical and nonclinical samples.

The purpose of this study was to determine the constructs measured by the WISC-IV and the consistency of measurement across large normative and clinical samples. Competing higher order four-and five-factor models were analyzed using the WISC-IV normative sample and clinical subjects. The four-factor solution is the model published with the test manual. In the five-factor model, the POI differentiated into a visual-spatial factor (consisting of Block Design and Picture Completion) and a fluid reasoning factor (consisting of Matrix Reasoning and Picture Concepts, with and Arithmetic). The five-factor solution included Inductive Reasoning (IR), consisting of Matrix Reasoning and Picture Concepts, as a narrow ability subsumed under the FRI (Gf). When all 15 WISC-IV subtests were considered, both four-and five-factor models were suitable and showed close model-data fit. Further, both models generally demonstrated full factorial invariance between clinical and nonclinical samples. Interpretation of the fifth factor is discussed.

We tested a hypothesis that children with sickle cell disease who are completely normal by magnetic resonance imaging can still be cognitively impaired, as predicted by a model of diffuse brain injury. Fifty-four patients with hemoglobin SS (average age 10.9 years +/- 2.9 years SD) were examined with the Wechsler Intelligence Scale for Children-III (WISC-III) and were randomly matched by age, race, and gender with healthy children from the Wechsler normative database. Patients were also imaged at 1.5 Tesla with standard imaging sequences. Among 30 patients who were normal by magnetic resonance imaging, there were substantial deficits in Wechsler Full-Scale IQ, Verbal IQ, and Performance IQ (all P < .01) compared with African-American controls. The patient Wechsler Full-Scale IQ was 12.9 points lower than that of controls and decreased as a function of age (probability = .014). The findings suggest that there is diffuse brain injury in patients and that patient deficits increase with age.

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(1989) shows a difference of only 2.5 points. However, they have only five subtests in common when full scale IQ is calculated. If one simulates a comparison of the WISC-III and WISC-IV standardization samples on the 10 subtests of the WISC-III, IQ gains over the intervening 12.75 years were no less than 3.83 points, yielding a minimum estimate of 0.300 points per year. Finally, WISC subtest trends taken in conjunction with "the Nation's Report Card" (NAEP test trends) provide a fascinating picture of the evolution of cognitive skills in America over the last two generations. Key words: Flynn effect, IQ gains, education gainsIQ trends over time are the product of factors that fluctuate over time and therefore must be estimated anew whenever fresh data become available. We are not sure of the exact causes, but putative causes for the post-1932 era, at least in developed na-