From Wikipedia, the free encyclopedia

Wechsler Adult Intelligence Scale or WAIS is a general test of intelligence (IQ), published in February 1955 as a revision of the Wechsler-Bellevue test (1939), standardised for use with adults over the age of 16.

Intelligence is quantified as the global capacity of the individual to act purposefully, to think rationally, and to deal effectively with the environment.

Contents 1 Overview 2 Test variants 3 14 subtests of the WAIS-III 3.1 Verbal Subtests 3.2 Performance Subtests 4 WAIS-III Subtests Grouped According to Indices 4.1 Verbal comprehension 4.2 Perceptual organization 4.3 Working memory 4.4 Processing speed 5 See also 6 External links

The full scale IQ is broken down into 14 subtests, comprising the verbal (7 subtests) and performance scales (7 subtests).

Wechsler's tests provide three scores:

1. a verbal IQ
2. a performance IQ
3. a composite, single full-scale IQ score based on the combined scores.

WAIS-R was standardised in 1981 on a sample of 1,880 US subjects, ranging from 16 to 74 years of age, broken down into 9 different age groups. It is considered to have very strong reliability. The current version is WAIS-III (1997).

The average full-scale IQ is 100, with a standard deviation of 15 (above and below the mean). This is the average IQ range where most adults would fall.

The WAIS-III measure is appropriate throughout adulthood and for use with those individuals over 74 years of age. For persons under 16, the Wechsler Intelligence Scale for Children (WISC, 7-16 yrs) and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI, 2 1/2-7 yrs) are used.

An IQ score can be obtained without administering the verbal section of the test since each section yields its own score.

Neuropsychologists use the technique on people suffering brain damage as it leads to links with which part of the brain has been affected, or use specific subtests in order to get an idea of the extent of the brain damage. For example, digit span may be used to get a sense of attentional difficulties. However, this is usually done with a separate version of the WAIS, known as the WAIS-R NI (Wechsler Adult Intelligence Scale-Revised as a Neuropsychological Instrument). Each subtest score is tallied and calculated with respect to non-normal or brain-damaged norms. As the WAIS is developed for the average, non-injured individual, separate norms were developed for appropriate comparison among similar functioning individuals.

A short, four-subtest, version of the battery has recently been released, allowing clinicians to form a validated estimate of verbal, performance and full scale IQ in a shorter amount of time. The Wechsler Abbreviated Scale of Intelligence (WASI) uses the vocabulary, similarities, block design and matrix reasoning subtests of the WAIS to provide an estimate of the full IQ scores.

Information 

Degree of general information acquired from culture (e.g. Who is the premier of Victoria?)

Comprehension

Ability to deal with abstract social conventions, rules and expressions (e.g. What does - Kill 2 birds with 1 stone metaphorically mean?)

Arithmetic

Concentration while manipulating mental mathematical problems (e.g. How many 45c. stamps can you buy for a dollar?)

Similarities/Differences

Abstract verbal reasoning (e.g. In what way are an apple and a pear alike and/or unalike?)

Vocabulary

The degree to which one has learned, been able to comprehend and verbally express vocabulary (e.g. What is a guitar?)

Digit span

attention/concentration (e.g. Digits forward: 123, Digits backward 321.)

Letter-Number Sequencing

attention and working memory (e.g. Given Q1B3J2, place the numbers in numerical order and then the letters in alphabetical order)

Picture Completion

Ability to quickly perceive visual details

Digit Symbol - Coding

Visual-motor coordination, motor and mental speed

Block Design

Spatial perception, visual abstract processing & problem solving

Matrix Reasoning

Nonverbal abstract problem solving, inductive reasoning, spatial reasoning

Picture Arrangement

Logical/sequential reasoning, social insight

Symbol Search

Visual perception, speed

Object Assembly

Visual analysis, synthesis, and construction

Optional post-tests include Digit Symbol - Incidental Learning and Digit Symbol - Free Recall.

In addition to the Verbal and Performance IQ scores, the following four indices are derived.

• Vocabulary

• Information

• Similarities

• Picture Completion
• Block Design
• Matrix Reasoning

• Arithmetic
• Digit Span
• Letter-Number Sequencing

• Digit Symbol-Coding
• Symbol Search

Note: Picture Arrangement, Comprehension, and Object Assembly do not contribute to the Index Scores'

• David Wechsler
• Wechsler Intelligence Scale for Children (WISC)
• Wechsler Preschool and Primary Scale of Intelligence (WPPSI)

• Overview
• Official page
• More descriptions about individual tests
• PMID 12801187 - "Scoring reliability on the Wechsler Adult Intelligence Scale-Third Edition"
• PMID 10877468 - "Prorating Wechsler Adult Intelligence Scale-III summary scores"