Wechsler Intelligence Scale for Children

Overview
The Wechsler Intelligence Scale for Children (WISC), developed by David Wechsler, is an intelligence test for children between the ages of 6 and 16 inclusive that can be completed without reading or writing. The WISC generates an IQ score.

History
The WISC was originally developed as a downward extension of the Wechsler Adult Intelligence Scale in 1949. A revised edition (WISC-R) in 1974 as the WISC-R, and the third edition, the WISC-III in 1991. The current version, the WISC-IV, was produced in 2003. Each successive version has renormed the test to compensate for the Flynn effect, refined questions to make them less biased against minorities and females, and updated materials to make them more useful in the administration of the test.

Uses
The WISC is used not only as an intelligence test, but as a clinical tool. Many practitioners use it to diagnose attention-deficit hyperactivity disorder (ADHD) and learning disabilities, for example. This is usually done through a process called pattern analysis, in which the various subtests' scores are compared to one another (ipsative scoring) and clusters of unusually low scores in relation to the others are searched for. David Wechsler himself suggested this in 1958 (Kaplan & Saccuzzo, 2005).

However, the research does not show this to be a very effective way to diagnosis ADHD or learning disabilities (Watkins, Kush, & Glutting, 1997). The vast majority of ADHD children do not display certain subscores substantially below others, and many children who display such patterns do not have ADHD. Other patterns for children with learning disabilities show a similar lack of usefulness of the WISC as a diagnostic tool (Ward, Ward, Hatt, Young, & Moller, 1995).

When diagnosing children, best practice suggests that a multi-test battery should be used as learning problems, attention, and emotional difficulties can have similar symptoms, co-occur, or influence each other. For example, children with learning difficulties can become emotionally distraught and thus have concentration difficulties, begin to exhibit behavior problems, or both. Children with ADD or ADHD may show learning difficulties because of their attentional problems or also have learning disorder or mental retardation (or have nothing else). In short, while diagnosis of any childhood or adult difficulty should never be made based on IQ alone (or interview, physician examination, parent report, other test etc. for that matter) the cognitive ability test can help rule out, in conjunction with other tests and sources of information, other explanations for problems, uncover co-morbid problems, and be a rich source of information when properly analyzed and care is taken to avoid relying simply on the single summary IQ score (Sattler, ?year).

The empirical consensus is that the WISC is best used as a tool to evaluate intelligence and not to diagnose ADHD or learning disabled children. However, many clinicians use it to compare a child's cognitive development to his or her actual school or social performance. Using this discrepancy and other sources of data, the WISC can contribute information concerning a child's psychological well-being.

Translations
WISC has been translated or adapted to many languages, and norms have been established for a number of countries, including Spanish, Norwegian, Swedish, French (France and Canada), English (United States, Canada, United Kingdom), Chinese (Hong Kong), Greek, and Italian. Separate norms are established with each translation. (Norway uses the Swedish norms).