Wechsler intelligence test

Encyclopedia of Medicine, Apr 06, 2001 by Paula Anne Ford-Martin

The Wechsler Intelligence Scales are a series of standardized tests used to evaluate cognitive abilities and intellectual abilities in children and adults.

The Wechsler Intelligence Scales for Children (regular, revised, and third edition) and Wechsler Preschool and Primary Scale of Intelligence are used as tools in school placement, in determining the presence of a learning disability or a developmental delay, in identifying giftedness, and in tracking intellectual development.

The Wechsler Adult Intelligence Scales (regular and revised) are used to determine vocational ability, to assess adult intellectual ability in the classroom, and to determine organic deficits. Both adult and children's Wechsler scales are often included in neuropsychological testing to assess the brain function of individuals with neurological impairments.

Intelligence testing requires a clinically trained examiner. The Wechsler scales should be administered, scored, and interpreted by a trained professional, preferably a psychologist or psychiatrist.

All of the Wechsler scales are divided into six verbal and five performance subtests. The complete test takes 60-90 minutes to administer. Verbal and Performance IQs are scored based on the results of the testing, and then a composite Full Scale IQ score is computed. Although earlier editions of some of the Wechsler Scales are still available, the latest revisions are described below:

The WAIS-R, the 1981 revision of the original Wechsler Adult Intelligence Scale, is designed for adults, age 16-74. The 11 subtests of the WAIS-R include information, digit span, vocabulary, arithmetic, comprehension, similarities, picture completion, picture arrangement, block design, object assembly, and digit symbol. An example of questions on the subtest of similarities might be: "Describe how the following pair of words are alike or the same--hamburger and pizza." A correct response would be "Both are things to eat."

The WISC-III subtests includes many of the same categories of subtests as the WAIS-R. In addition, there are two optional performance subtests: symbol search and mazes.

The WPPSI is designed for children age 4-6½ years. The test is divided into six verbal and five performance subtests. The eleven subtests are presented in the following order: information, animal house and animal house retest, vocabulary, picture completion, arithmetic, mazes, geometric design, similarities, block design, comprehension, and sentences.

The 1997 Medicare reimbursement rate for psychological and neuropsychological testing, including intelligence testing, is $58.35 an hour. Billing time typically includes test administration, scoring and interpretation, and reporting. Many insurance plans cover all or a portion of diagnostic psychological testing.

The Wechsler Intelligence Scales are standardized tests, meaning that as part of the test design, they were administered to a large representative sample of the target population, and norms were determined from the results. The scales have a mean, or average, standard score of 100 and a standard deviation of 15. The standard deviation indicates how far above or below the norm the subject's score is. For example, a ten-year-old is assessed with the WISC-III scale and achieves a full-scale IQ score of 85. The mean score of 100 is the average level at which all 10-year-olds in the representative sample performed. This child's score would be one standard deviation below that norm.

While the full-scale IQ scores provide a reference point for evaluation, they are only an average of a variety of skill areas. A trained psychologist will evaluate and interpret an individual's performance on the scale's subtests to discover their strengths and weaknesses and offer recommendations based upon these findings.

• Books
• Maddox, Taddy. Tests: A Comprehensive Reference for Assessments in Psychology, Education, and Business. 4th ed. Austin, TX: Pro-ed, 1997.
• Shore, Milton F., Patrick J. Brice, and Barbara G. Love. When Your Child Needs Testing. New York, NY: Crossroad Publishing, 1992.
• Wodrich, David L. Children's Psychological Testing: A Guide for Nonpsychologists. Baltimore, MD: Paul H. Brookes Publishing, 1997. Periodicals
• Czubaj, Camilla Anne. "The Wechsler Adult Intelligence Scale--Revised, Revisited." Education 117, no. 3 (Winter 1997): 271-3.
• Slate, John R., Craig H. Jones. "WISC-III IQ Scores and Special Education Diagnosis." The Journal of Psychology 131, no. 1 (Jan 1997): 119-120. Organizations
• The American Psychological Association. 750 First St., NE, Washington, DC 20002-4242. (202) 336-5500. http://www.apa.org/psychnet.
• The Catholic University of America. Washington, DC 20064. (800) 464-3742. http://www.ericae.net.