Wechsler Adult Intelligence Scale

Purpose: Designed as a general test of cognitive ability for adults.

Population: Ages 16 and above.

Score: Verbal IQ, Performance IQ, and Full Scale IQ.

Time: (90-120) minutes.

Author: David Wechsler.

Publisher: The Psychological Corporation.

Description: The Wechsler Adult Intelligence Scale (WAIS) is a general test of cognitive ability, which Wechsler defined as, "... the global capacity of the individual to act purposefully, to think rationally, and to deal effectively with his environment." In keeping with this definition of intelligence as an aggregate of mental aptitudes or abilities, the WAIS consists of 11 subtests divided into two parts, verbal and performance.

Scoring: The WAIS consists of six verbal subtests and five performance subtests. The verbal tests are: Information, Comprehension, Arithmetic, Digit Span, Similarities, and Vocabulary. The Performance subtests are: Picture Arrangement, Picture Completion, Block Design, Object Assembly, and Digit Symbol. The scores derived from this test are a Verbal IQ (VIQ), a Performance IQ (PIQ), and a Full Scale IQ (FSIQ). The FSIQ is a standard score with a mean of 100 and a standard deviation of approximately 15.

Reliability: Split-half reliability coefficients (corrected) of .97 for FSIQ, .96 for VIQ, and .93 for PIQ are reported by Wechsler. Test-retest coefficients from .84 to .90 for intervals of 0 to 520 weeks are also reported. Intercorrelations of the subtests and correlations of each subtest with FSIQ indicate both uniqueness and communality for the subtests.

Validity: Predictive validity of the WAIS yields correlations of .60 in high school and a little lower for college. Factor analytic studies and confirmed good construct validity generally showing three to five factors, and usually tow of these can be related to the VIQ and PIQ.

Norms: The standardization sample included 2,700 subjects intended to be representative of the general American population. The 1950 census was used to select a sample stratified by age, sex, occupation, geographical distribution, education, and urban-rural residence. About 10% of the sample were non-white.

Suggested Uses: The WAIS is recommended for use in clinical, educational, and research settings.