Matters of Consequence - An Empirical Investigation of the WAIS-III and WAIS-IV - and Implications for Addressing the Atkins Intelligence Criterion

Sep 30, 2026

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Examines whether the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) or the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) provides the better measurement of intelligence in forensic contexts. The study addresses high-impact Atkins cases where courts confront divergent Full-Scale IQ (FSIQ) results. Structural equation modeling compares instruments using FSIQ and related scoring structures, concluding that WAIS-IV delivers superior measurement, scoring, and structural modeling for FSIQ compared with WAIS-III.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages22

Reading Time55 min

AccessFree to download

Historical Overview

Wechsler scales and FSIQ development

The WAIS-IV

Revision Goals

Downloaded by [New York University] at 19:22 28 January 2013 Journal of Forensic Psychology Practice, 13:27–48, 2013 Copyright © Taylor & Francis Group, LLC ISSN: 1522-8932 print/1522-9092 online DOI: 10.1080/15228932.2013.746913 Matters of Consequence: An Empirical Investigation of the WAIS-III and WAIS-IV and Implications for Addressing the Atkins Intelligence Criterion GORDON E. TAUB, PhD School Psychology Program, University of Central Florida, Orlando, Florida NICHOLAS BENSON, PhD Counseling and Psychology in Education, The University of South Dakota, Vermillion, South Dakota “Which test provides the better measurement of intelligence, the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) or the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV)?” is an important question to professional psychologists; however, it has become a critical issue in Atkins cases wherein courts are often presented with divergent Full-Scale IQ (FSIQ) scores on the WAIS-III and WAIS-IV. In these instances, courts are required to render a decision stating which test provided the better measure of an inmate’s intellectual functioning. This study employed structural equation modeling to empirically determine which instrument; the WAIS-III or the WAIS-IV, provides the better measure of intelligence via the FSIQ score. Consistent with the publisher’s representation of intellectual functioning, the results from this study indicate the WAIS-IV provides superior measurement, scoring, and structural models to measure FSIQ when compared to the WAIS-III. KEYWORDS Atkins, intelligence, intelligence quotient, expert testimony, Wechsler Adult Intelligence Scale Address correspondence to Gordon E. Taub, School Psychology Program, University of Central Florida, 4000 Central Florida Blvd. , Suite CED 123K, Orlando, FL 32816 . E-mail: [gtaub@ucf.edu](gtaub@ucf.edu) Downloaded by [New York University] at 19:22 28 January 2013 28 G. E. Taub and N. Benson HISTORICAL OVERVIEW The ﬁrst Wechsler scale, the Wechsler-Belleview Intelligence Scale (WBIS; Wechsler, 1939) was published in 1939 . The WBIS divided the measurement of intelligence into two factors: Verbal and Performance. These two factors were combined, and their sum was transformed into one’s full-scale intelligence quotient (FSIQ) . The Wechsler Adult Intelligence Scale (WAIS; Wechsler, 1955) was created as a revision to the WBIS in 1955 . The WAIS included revisions to the instrument’s administration, items, and scoring. The WAIS retained the 11 subtests included in the WBIS. The WAIS was followed by the publication of the Wechsler Adult Intelligence Scale-Revised (WAIS-R; Wechsler, 1981) . The revision to the WAIS-R included administration, item, and scoring changes. All 11 subtests from the WBIS and the WAIS were retained in the WAIS-R. The WAIS-R was replaced by the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; Wechsler, 1997a) . The WAIS-III retained the same subtests from the WAIS-R; however, three new subtests were added. The subtest Matrices was the only new subtest contributing to the calculation of an individual’s FSIQ; the other two subtests were supplemental. The WAIS-III was scored in a manner identical to that of its predecessors using the traditional Verbal IQ, Performance IQ, and FSIQ scoring structure. There was one significant addition to the WAIS-III: a new four-factor clinical model, which was independent from the instrument’s FSIQ measurement and scoring model. Although the research has demonstrated the WAIS-III’s measurement model is invariant across the instrument’s standardization sample, the new fourfactor clinical model provided a better ﬁt to the WAIS-III’s standardization data when compared to the FSIQ measurement and scoring model (i.e. , Verbal/Performance scoring model; Taub, 2001; Taub, McGrew, & Witta, 2004) . The FSIQ scoring model of the Wechsler scales, via the Verbal/ Performance scoring method, was present

FAQs

Why is the WAIS-III vs. WAIS-IV comparison important in Atkins cases?

Courts often receive divergent Full-Scale IQ (FSIQ) scores from WAIS-III and WAIS-IV and must decide which test better measures an inmate’s intellectual functioning.

How did the study determine which WAIS edition provides the better intelligence measurement?

It used structural equation modeling to compare how well WAIS-III versus WAIS-IV measures intelligence via FSIQ and associated structural models.

What conclusion did the study reach about WAIS-IV compared with WAIS-III?

Results indicate WAIS-IV provides superior measurement and scoring, with better-fitting structural models for FSIQ than WAIS-III.

Sep 30, 2026

Upload by Franzy