Foreword

The publication of the WISC-V marks a milestone in children’s test development. It was published during a year—2014—when other state-of-the-art intelligence tests were also published, namely the CHC-based Woodcock-Johnson IV (Schrank, McGrew, Mather, & Woodcock, 2014) and the Luria-based Cognitive Assessment System—2nd edition (CAS2) (Naglieri, Das, & Goldstein, 2014). The competition for supremacy is steep and the WISC-V has met the challenge. The battery is comprehensive, versatile, child oriented, and clinically rich. It is steeped in a variety of well-researched and well-articulated theories that have roots in cognitive neuroscience, neuropsychological processing, and the CHC model that has expanded from a simple Cattell-Horn fluid-crystallized dichotomy (not unlike Wechsler’s original Verbal-Performance distinction) to an array of important cognitive abilities. The developers of the WISC-V have met the challenges of this RTI-dominated and theory-driven decade with much the same goal-directed and ingenious fervor that characterized the great Dr. David Wechsler more than 75 years ago.

Indeed, Dr. Wechsler challenged the Stanford-Binet in the 1930s when no one else had either the courage or the inspiration. The original Stanford-Binet, published in 1916 by Lewis Terman, had many challengers (e.g., Goddard-Binet, Kuhlmann-Binet), all of whom were tied to Alfred Binet’s groundbreaking age-based scale normed on Paris students. After Terman triumphed, largely because he had the insight to rearrange the Binet tasks assigned to each age level based on American data, and to actually obtain norms for children and adolescents living in the United States, his Binet test reigned as the measure of IQ.

That reign solidified in 1937 when Terman added a coauthor (Maud Merrill—like Terman, a professor at Stanford), an alternate form (the new Binet boasted Forms L and M), and a sophisticated statistical treatment of the data, thanks in large part to Dr. Quinn McNemar. Noted educator Ellwood P. Cubberly (1937) wrote in the Editor’s Introduction to the test manual, “after ten years of painstaking research, two new and equivalent scales, each more extensive than the original both in range and in number of tests, and each providing for greater objectivity in scoring, are at last ready for public use” (pp. vi–vii).

Dr. Wechsler was not intimidated by the thoroughly revised and expanded Binet, touted in its own manual as the IQ test to end all IQ tests. He had vision. He insisted that a Performance Scale was just as necessary as a Verbal Scale to gain a full understanding of a person’s mental functioning. Never mind the critics who asked unabashedly, “Why would anyone waste 3 minutes administering a single puzzle to an English-speaking person when a dozen or more Vocabulary words can be administered in the same time frame?” He offered the sophisticated standard score statistic to replace the antiquated and inadequate MA/CA X 100 formula. Terman and Merrill (1937) were well aware of standard scores; they provided a table that converted IQs to standard scores in the test manual, and praised the metric: “From the statistical point of view, every advantage is in favor of the standard score” (p. 27). Yet they continued to derive IQs by formula because “the majority of teachers, school administrators, social workers, physicians, and others who utilize mental test results have not learned to think in statistical terms. To such a person a rating expressed as ‘+2 sigma’ is just so much Greek” (Terman and Merrill, 1937: 27–28).

Dr. Wechsler, never condescending to test users, knew better. When he published the Wechsler-Bellevue for children and adults (Wechsler, 1939), a scant 2 years after the revised Binet became available, he included state-of-the-art Performance subtests as a featured IQ scale and he never doubted that clinicians were smart enough to “speak Greek.” Those two departures from tradition moved the field of intellectual assessment a couple of light years forward.

Dr. Wechsler single-handedly changed the face of intellectual assessment from psychometric to clinical. The Binet tradition, as expounded by Terman and McNemar, was psychometric in orientation. Dr. Wechsler changed that when he published the Wechsler-Bellevue in 1939 and wrote incisively about how to interpret his tests in clinical practice (Wechsler, 1939, 1950, 1958; see also Chapters 8–10 of this book). The field of clinical assessment was born, and, except for some purists who insist that subtest profile interpretation and qualitative analysis of test scores are sacrilegious (for example, McDermott, Fantuzzo, & Glutting, 1990), the practices of clinical assessment have thrived internationally and span the domains of clinical psychology, neuropsychology, and school psychology. Any time a child, adolescent, or adult is tested anywhere in the world, the imprint of Dr. Wechsler reverberates.

Dr. Wechsler’s tests continue to dominate the IQ scene. More than 75 years after the original Wechsler-Bellevue was published, Wechsler’s scales stand at the very top of the assessment dome for the assessment across the lifespan, from preschool to old age. The WISC-IV has clearly been the most popular IQ measure for children and adolescents, but it has had some company on the assessment scene in schools, clinics, and private practices. Other acronyms have also been tossed about over the past decade when choosing a children’s test for this or that type of referral, such as the CAS (Naglieri & Das, 1997) and now the CAS2 (Naglieri et al., 2014); the DAS-II (Elliott, 2007), KABC-II (Kaufman & Kaufman, 2004), RIAS (Reynolds & Kamphaus, 2003), and SB-5 (Roid, 2003); and the WJ-IV (Schrank et al., 2014). However, despite the raising of the bar to unprecedented heights, the WISC-V will undoubtedly continue to carry the international torch of intellectual assessment in the school-age range.

How Dr. Wechsler’s legacy lives on! The chapters in this book attest to the WISC-V’s superior psychometric and practical features, and demonstrate the test’s contextual role within the theoretical, clinical, and research domains of assessment and, more broadly, within society. This volume, authored by the excellent team of Larry Weiss, Don Saklofske, Jim Holdnack, and Aurelio Prifitera, provides a compelling story of the WISC-V and its clinical use and interpretation. They and the varied contributors to this book represent some of the best that the field of intellectual assessment has to offer from the clinical, neuropsychological, and psychometric realms.

In Chapter 1, Weiss et al. offer a compelling introduction to the historical evolution of the WISC. Major innovations in the test model have characterized each revision of the scale. The development of the scale is traced from its origins in the Wechsler-Bellevue Intelligence Scale (Wechsler, 1939) to the present-day WISC-V (Wechsler, 2014), the subject of this book. The authors note that while the scale’s evolution has been guided at The Psychological Corporation/Pearson through an emphasis on clinical research in neuropsychology and information processing, theory-based approaches to analysis derive “surprisingly similar models of intelligence based on different lines of research.” Furthermore, Weiss et al. provide a history of the new fluid reasoning index, which has “been a systematic research goal since 1997, leading to the development and validation of three fluid reasoning subtests introduced successively in various subsequent editions; Matrix Reasoning, Picture Concepts, and Figure Weights.” The chapter concludes with an overview of the test structure, which is at its heart familiar but contains a host of ancillary and complementary measures that enhance the clinical utility of the test for special uses.

In addition to the noticeable changes to the test structure, the WISC-V provides the option of a digital version on Q-interactive, which is a platform that provides the capability to administer tests on iPads and other tablets. Chapter 11 provides an overview of the Q-interactive system and examples of how the subtests are administered within the digital format. Wahlstrom and colleagues review the accumulated evidence of equivalence of the digital and paper versions of both the WISC-IV and the WISC-V, and discuss the implications on the potential to engage the child more readily as well as the potential for future data capture to measure constructs impossible to measure within a paper-and-pencil format.

In Chapter 5, the authors answer the “simple” psychometric question of the size of the ethnic differences for the Full Scale IQ and each primary index score. A regression approach is then used to explain increasingly the variability gaps in Full Scale IQs by race/ethnicity with other factors previously discussed, the distributions of which also have been shown to vary across racial/ethnic groups, such as marital status of parents and the number of parents in the home. Dr. Wechsler would have been fascinated by this research because he was always impressed that factor analyses of his scales only accounted for about 60% of the variance.

Dr. Wechsler was...