About the Wechsler Adult Intelligence Scale (WAIS)
The Wechsler Adult Intelligence Scale (WAIS), first published by psychologist David Wechsler in 1955, is the most widely used adult IQ test in the world; it introduced the deviation IQ (mean of 100, standard deviation of 15) and reports a Full Scale IQ alongside index scores for verbal comprehension, perceptual reasoning, working memory, and processing speed.
In 1955 David Wechsler published the Wechsler Adult Intelligence Scale, a major revision of his 1939 Wechsler-Bellevue. The WAIS was renormed on a representative US sample (1,700 adults aged 16-64) and introduced the deviation-IQ scoring system: rather than the mental-age-divided-by-chronological-age IQ that Terman had used since 1916, Wechsler scaled raw scores so the population mean was 100 and the standard deviation was 15. This was a fundamental improvement and has been used by every IQ test since.
The WAIS had 11 subtests: 6 Verbal (Information, Comprehension, Arithmetic, Similarities, Digit Span, Vocabulary) and 5 Performance (Digit Symbol, Picture Completion, Block Design, Picture Arrangement, Object Assembly). Each subtest yielded a scaled score; the sum produced Verbal IQ, Performance IQ, and Full Scale IQ.
The WAIS dominated adult intelligence assessment for 25 years until the WAIS-R (1981), then WAIS-III (1997), WAIS-IV (2008), and now WAIS-5 (2024). The basic 11-subtest structure has been refined but not abandoned. WAIS-IV is the world's most-administered adult IQ test, with millions of administrations per year. Pearson holds active copyright; the original 1955 manual is widely cited but the items themselves are commercially protected.
The 11 subtests
Sample Items (Illustrative)
Items are presented orally or visually, and responses are scored based on accuracy, completeness, and sometimes speed, depending on the subtest. Each subtest focuses on a specific cognitive ability and requires different types of responses, from verbal answers to physical manipulation of objects.
Source
0 bill, how much change should you receive?These are illustrative samples, not actual items from the protected test.
Source
All test materials and historical content on this page are transcribed from:
Wechsler, D. (1955). Manual for the Wechsler Adult Intelligence Scale. New York: Psychological Corporation.
WAIS items are copyrighted (Pearson/NCS Pearson, successor to The Psychological Corporation). We document the test's history and significance with illustrative sample items, not actual WAIS items.
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Take the Modern IQ TestFrequently asked questions
What is the Wechsler Adult Intelligence Scale (WAIS)?
The Wechsler Adult Intelligence Scale (WAIS) is an individually administered IQ test for adults and older adolescents, first published by psychologist David Wechsler in 1955. It measures general cognitive ability and produces a Full Scale IQ score, along with separate index scores covering different mental abilities. It remains the most widely used adult intelligence test in the world.
Who created the WAIS and in what year?
The WAIS was created by American psychologist David Wechsler and published in 1955. It evolved from his earlier Wechsler-Bellevue Intelligence Scale of 1939. Wechsler designed it specifically for adults, in contrast to earlier tests like the Stanford-Binet that were oriented toward children, and his name continues to define the test through every revised edition.
What does the WAIS measure and how is it scored?
The WAIS measures general intelligence and reports a Full Scale IQ plus four index scores: Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed. Scores use the deviation IQ system that Wechsler pioneered, with a mean of 100 and a standard deviation of 15. This means a score of 100 is exactly average, and most people fall between 85 and 115.
What is the deviation IQ that the WAIS introduced?
The deviation IQ is a scoring method introduced by the WAIS in 1955 that compares a person's performance to others in their age group, rather than dividing mental age by chronological age. It sets the average at 100 with a standard deviation of 15. This approach replaced the older ratio IQ (mental age divided by chronological age, times 100), which did not work well for adults, and it is now the standard for nearly all modern IQ tests.
Is the WAIS still used today, and is there a modern version?
Yes, the WAIS is still used and is the most widely used adult IQ test in the world. The original 1955 version has been revised several times and is now in its fifth edition, the WAIS-5, released in 2024. Clinical psychologists, neuropsychologists, and educational professionals use it for assessing intellectual ability, diagnosing cognitive conditions, and evaluating learning or workplace accommodations.
How is the WAIS different from a free online IQ test?
The WAIS is a professionally administered test given one-on-one by a trained clinician, scored against carefully developed age-based norms, and used for clinical and diagnostic decisions. Free online IQ tests are self-administered, unstandardized, and not validated, so their results are not equivalent to a WAIS score. Only a qualified examiner can administer the genuine WAIS, and its deviation IQ scoring (mean 100, standard deviation 15) is what gives the result clinical meaning.