Wechsler Intelligence Scale

Ronald Jay Cohen and Mark E. Swerdlik, www.answers.com

Definition

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 tests are a widely used series of intelligence tests developed by clinical psychologist David Wechsler.

Purpose

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. They are often included in neuropsychological testing to assess the brain function of individuals with neurological impairments.

Description

The most distinctive feature of the Wechsler tests is their division into a verbal section and a nonverbal (or performance) section, with separate scores available for each subsection. 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. Verbal intelligence, the component most often associated with academic success, implies the ability to think in abstract terms using either words or mathematical symbols. Performance intelligence suggests the ability to perceive relationships and fit separate parts together logically into a whole. The inclusion of the performance section in the Wechsler scales is especially helpful in assessing the cognitive ability of non-native speakers and children with speech and language disorders. The test can be of particular value to school psychologists screening for specific learning disabilities because of the number of specific subtests that make up each section. Although earlier editions of some of the Wechsler Scales are still available, the latest revisions are described below:

Wechsler Adult Intelligence Scale-Revised (WAIS-R)

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 WAIS – R  was organized into verbal and performance scales. Scoring yielded a verbal IQ, a performance IQ, and a full scale IQ. The test was carefully constructed and standardized and quickly become “ the standard against which other adult tests can be compared” (Lyman, 1972, p. 429). The need for a more contemporary norm group soon became evident, and a revision of the test, the WAIS – R, was published in 1981 shortly after Wechsler’s death. In addition to new norms and updated materials, the administration instructions were changed to mandate alternation between verbal and performance tests. In 1997, the third edition of the test (the WAIS – III) was published, with authorship credited to David Wechsler.

Wechsler Intelligence Scale for Children, Third Edition (WISC-III)

The WISC-III subtests includes many of the same categories of subtests as the WAIS-R. The Wechsler Intelligence Scale for Children (WISC) is designed for children and adolescents ages six to 16. Its makeup is similar to that of the Preschool Scale. Differences include the following: geometric designs are replaced by assembly of three-dimensional objects; children arrange groups of pictures to tell simple stories; they are asked to remember and repeat lists of digits; a coding exercise is performed in place of the animal house; mazes are a subtest

Wechsler Preschool and Primary Scale of Intelligence (WPPSI)

The Wechsler Preschool and Primary Scales of Intelligence (WPPSI) have traditionally been geared toward children ages four to six years old, although the newest version of the test extends the age range down to three years and upward to seven years three months. The verbal section covers the following areas: general information (food, money, the body, etc.), vocabulary (definitions of increasing difficulty), comprehension (responses to questions), arithmetic (adding, subtracting, counting), sentences (repeating progressively longer sentences), and similarities (responding to questions such as "How are a pen and pencil alike?"). The performance section includes picture completion, copying geometric designs, using blocks to reproduce designs, working through a maze, and building an animal house from a model. 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.

Risks

The only known risk of the Wechsler intelligence tests is that the results are misused or are given undue weight.