Use of the WISC-IV for Gifted Identification

School districts use multi-faceted approaches to identify gifted students.  Some states and districts employ comprehensive individual IQ tests as one of several identifiers.  The most popular of these is the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) (Lubin, Wallis & Paine, 1971).  Even in districts where IQ tests are not used in student selection, the WISC-IV is often administered when the parents appeal the decision to deny a child services. 

Also, for twice exceptional children, the WISC-IV plays an important role in documenting the child’s giftedness and learning deficits, as well as revealing the giftedness of children with expressive, physical, or other disabilities.  In prior versions of the Wechsler scales, the child’s Full Scale IQ score has been the primary determining factor in placement.  However, the Full Scale IQ score of the WISC-IV often does not represent a child’s intellectual abilities as well as the General Ability Index.  Therefore, some guidelines for test interpretation are necessary. 

This position statement is designed for school psychologists, coordinators of gifted programs, teachers, and all professionals who determine placements based on IQ scores or design services based on a child’s strengths and weaknesses. It is also provided for parents so they can better understand the interpretation of their children’s scores. It is not intended to narrow the choice of tests in the selection of gifted students, but to broaden the guidelines for use of the WISC-IV and prevents its use in a way that is disadvantageous to gifted children. 

The WISC-IV was standardized on 2200 children, including Caucasians, African Americans, Hispanics, Asians, and others (a combined designation including Native Americans, Alaskan Natives, and other groups in the U.S.), in proportion to their distribution in the American population. Parental educational levels and geographic regions were also proportionately represented. In concert with the publishers’ concerns for “Suitability and Fairness,” greater flexibility is built into the administration of the WISC-IV:  examiners are permitted to use appropriate substitutions of subtests when necessary for equitability (Wechsler, 2003). Nevertheless, IQ tests should be interpreted cautiously for children from culturally and linguistically diverse backgrounds, and for all children, and should never be the only basis for exclusion from gifted programs.  In addition, all efforts should be made to accommodate linguistic diversity and test children in their native language.

The WISC-IV introduces important structural changes that compromise the relevance of the Full Scale IQ score (FSIQ) for gifted children.  The Verbal and Performance IQ scores of earlier versions of the scale have been replaced by four Composite/Index scores on the WISC-IV: Verbal Comprehension, Perceptual Reasoning, Working Memory and Processing Speed.  The weight of processing skills in the Full Scale IQ calculation has doubled, with a consequent reduction in the weight assigned to reasoning tasks (verbal, visual-spatial and mathematical).  Testers of the gifted know that abstract reasoning tasks best identify cognitive giftedness, while processing skills measures do not.  Gifted children with or without disabilities may be painstaking, reflective and perfectionistic on paper-and-pencil tasks, lowering their Processing Speed Index scores; to a lesser degree, they may struggle when asked to recall non-meaningful material (Digit Span, Letter-Number Sequencing), lowering their Working Memory Index, even though they excel on meaningful auditory memory tasks that pique their interest.