Technical and Practical Issues in the Structure and Clinical Invariance of the Wechsler Scales

Abstract

This discussion article addresses issues related to expansion of the Wechsler model from four to five factors; multiple broad CHC abilities measured by the Arithmetic subtest; advantages and disadvantages of including complex tasks requiring integration of multiple broad abilities when measuring intelligence; limitations of factor analysis, which constrain test developers to creating specific broad and narrow abilities as opposed to integrative tasks; implications from brain imaging research showing the critical role of neurological pathways that integrate brain regions; close relationship of the fluid reasoning factor to g, and the inadequacies of factor analytically driven statistical definitions of g in the development of improved models of intelligence. In this rejoinder to the commentaries in this special issue on structural models of the WAIS-IV and WISC-IV, the advantages and disadvantages of Schmid-Leiman's transformation, which removes the effects of g on the broad abilities, and the use of nested or bifactor models in evaluating models of intelligence are also discussed.This special issue is important because it contributes substantially to an ever-increasing body of knowledge that will allow us to build better models of intelligence in future editions of our intellectual assessment tools. We greatly appreciate the time and thought that each commentator has put into their reviews, and we are humbled by the largely positive attention that our work has received. We are especially grateful to Alan Kaufman for his insightful and balanced integration of the eight commentary papers (Kaufman, 2013). We divide our rejoinder into two broad sections on conceptual and practical issues, and technical and methodological issues.

Using Score Equating and Measurement Invariance to Examine the Flynn Effect in the Wechsler Adult Intelligence Scale

“…Some advocate using a higher order factor model, with first-order factors directly influencing the test scores and the second-order factor only directly influencing the first-order factors Weiss, Keith, Zhu, & Chen, 2013). In keeping with Carroll's (1993) terminology, we call the first-order factors Stratum II factors and the second-order factor g. In the higher order model, g only has an indirect relationship with the test scores.…”

“…As we discussed in the Introduction, the advantages of using a bi-factor model are manifold, but it is not the only model used to explain the covariance of the WAIS subtests. For example Weiss et al (2013) argued that a higher order model is better for the WAIS than a bi-factor model. Likewise, using an eightsubtest version of the WAIS-R, Horn and McArdle (1992) argued for using a two-factor model based on the theory of fluid and crystallized abilities.…”

Is the Cattell–Horn–Carroll-Based Factor Structure of the Wechsler Intelligence Scale for Children—Fifth Edition (WISC-V) Construct Invariant for a Representative Sample of African–American, Hispanic, and Caucasian Male and Female Students Ages 6 to 16 Years?

“…Arithmetic heavily loads on Gc and Gsm, as it requires the ability to use prior knowledge base in the application of novel math problems, read the question, and solve it both verbally and quantitatively, especially in higher grades (Wendling and Mather 2009). Arithmetic also requires the ability to keep information in the short-term memory and manipulate this information while solving the math task (Keith et al 2006;Weiss et al 2013). In fact, according to studies conducted with the WISC-V, Arithmetic tends to load on Gsm in a four-factor structure but on Gf in a five-factor structure (Wechsler 2014b).…”

Wisc-V

“…As the two target papers in the special issue of JPA, these papers were subject to invited critiques by eight prominent researchers, and generally positively reviewed (see Kaufman, 2013 for a summary and discussion of the reviews, and see Weiss, Keith, Zhu, & Chen, 2013c for a rejoinder). Thus, these papers served as the catalyst for a five factor model of WISC-V.…”