Guide
WAIS, Stanford-Binet, Raven's and Mensa tests compared
WAIS, Stanford-Binet, Raven's, Cattell, Mensa: the names come up whenever people compare IQ scores. They are not interchangeable. Here is what each one is, what it measures, and why the same person can get different numbers on them.
Want your own number? The test is 25 visual puzzles, about 12 minutes, no sign-up.
At a glance
| Test | First published | What it is |
|---|---|---|
| Wechsler scales (WAIS) | 1939 | Clinical battery; WAIS-IV 2008, WAIS-5 2024 |
| Stanford-Binet | 1916 | Clinical battery; fifth edition 2003 |
| Raven's Progressive Matrices | 1938 | Nonverbal matrix puzzles |
| Cattell Culture Fair | n/a | Nonverbal test; its III scale uses SD 24 |
| Mensa | n/a | A society, not a test; top 2% on approved tests |
The Wechsler scales
David Wechsler introduced the Wechsler-Bellevue scale in 1939, and with it the deviation IQ: a score based on standard scores, comparing you with people your own age (Wikipedia: WAIS). The adult version is the Wechsler Adult Intelligence Scale. WAIS-IV was published in 2008 and WAIS-5 in 2024.
Wechsler tests are full batteries: a trained examiner gives a series of verbal and nonverbal tasks, and the results combine into a full-scale IQ with a mean of 100 and a standard deviation of 15. The WAIS-IV is also the source of the classification labels most people have seen, from “Extremely Low” (69 and below) to “Very Superior” (130 and above) (Wikipedia: IQ classification). Our IQ score chart uses those labels.
The Stanford-Binet
The Stanford-Binet descends from the first practical intelligence test, published by Alfred Binet and Theodore Simon in 1905. Lewis Terman published the Stanford revision in 1916 (Wikipedia: Intelligence quotient), and the fifth edition (SB5), developed by Gale Roid, was published in 2003 (Wikipedia: Stanford-Binet).
Like the Wechsler scales, the modern Stanford-Binet is a clinical battery with a mean of 100 and a standard deviation of 15. Older Stanford-Binet forms used a standard deviation of 16 (Wikipedia: IQ classification), so a score of 132 on one of those forms sits at the same percentile as 130 on a modern test. That detail explains many confusing comparisons in older books and records.
Raven's Progressive Matrices
John C. Raven developed the Progressive Matrices in the 1930s, and they were first published in 1938. Each item is a grid of patterns with one piece missing, and you choose the piece that completes it. There are no words to read. Raven's matrices are widely used as a measure of fluid, culture-reduced reasoning (Wikipedia: Raven's Progressive Matrices), the ability Raymond Cattell later described as reasoning with novel material (Wikipedia: Fluid and crystallized intelligence).
Because the format is so clean, matrix puzzles have become the backbone of nonverbal testing, including the Abstract Reasoning section of IQ Octopus. Our guide to matrix reasoning shows how they are built.
Try one · Abstract Reasoning
Which tile completes the grid?
Tap the option you think is right, or show the answer.
Show the answer
The missing tile has one outlined triangle (option 7).
How to solve it
- Start with the first row and name what changes from tile to tile.
- Every row and every column contains each shape (triangle, cross and square) exactly once.
- Every row and every column contains each number of shapes (two, one and three) exactly once.
- The fill (outline) stays the same in every tile.
- Check the rules on the second row, then apply them to the third.
- So the missing tile has one outlined triangle.
That was 1 puzzle. The full test has 25.
The Cattell Culture Fair test
The Cattell Culture Fair tests also use nonverbal puzzles. Their most notable feature for anyone comparing scores is the scale: the Cattell Culture Fair III scale uses a standard deviation of 24 (Wikipedia: IQ classification). A score that reads 130 on a standard SD 15 test reads 148 on an SD 24 scale. Someone quoting a very high number from a Cattell test may be describing the same percentile as a much more ordinary-looking Wechsler score.
Mensa
Mensa is a society, not a test. It accepts people who score at or above the 98th percentile, the top 2%, on an approved, supervised standardized test (Mensa International). Because tests use different scales, the qualifying number changes with the test. Mensa UK quotes 148 on the Cattell III B and 132 on the Culture Fair test, both the 98th percentile on their own scales (Mensa UK). On a test with a standard deviation of 15, the 98th percentile is about 131.
Online tests, including IQ Octopus, cannot be used to join. If Mensa is your goal, the society can tell you which tests it accepts and how to sit one.
The current editions in numbers
| Test | Ages | Structure | Testing time |
|---|---|---|---|
| WAIS-5 (2024) | 16 to 90 | 5 primary indexes; FSIQ from 7 subtests | About 45 to 60 minutes (Pearson: WAIS-5) |
| WISC-V (2014) | 6 to 16 | 5 primary indexes; FSIQ from 7 subtests | About 60 minutes (Pearson: WISC-V) |
| Stanford-Binet 5 | 2 to 85+ | 5 factors in verbal and nonverbal domains, 10 subtests | About 5 minutes per subtest (PRO-ED: SB5) |
| Raven's (classic) | 5 and up, by form | Matrix puzzles only; SPM has 60 items | Untimed, about 20 to 45 minutes for the SPM (Pearson: Raven's brochure) |
| American Mensa test | 14 and up | Supervised admission test; 98th percentile qualifies | One to two hours (American Mensa: testing) |
Every test in the table has its own full guide in IQ tests, explained.
Why the same person gets different numbers
- Different scales. SD 15, 16 or 24 turn the same percentile into different numbers.
- Different content. A full battery samples verbal, nonverbal, memory and speed tasks. A matrix test samples one kind of reasoning. People with uneven profiles score differently on each.
- Different norms and dates. Each test compares you with its own reference sample, collected at a particular time. Average scores have drifted over the decades, which is why tests are re-standardized (see the Flynn effect).
- Measurement error. No test is exact. Two careful tests can disagree by several points without either being wrong.
When you compare scores, convert to percentiles first. The percentile to IQ converter does the arithmetic for all three common scales.
Where IQ Octopus fits
IQ Octopus is closest in spirit to the nonverbal tests: generated matrix, sequence, rotation, number series and analogy puzzles, reported on the standard scale with mean 100 and SD 15. It is a short online estimate, not a clinical battery. For when that difference matters, read online vs clinical IQ tests.
Sources
- Wechsler Adult Intelligence Scale. Wikipedia. en.wikipedia.org/wiki/Wechsler_Adult_Intelligence_Scale
- Stanford-Binet Intelligence Scales. Wikipedia. en.wikipedia.org/wiki/Stanford%E2%80%93Binet_Intelligence_Scales
- Raven's Progressive Matrices. Wikipedia. en.wikipedia.org/wiki/Raven%27s_Progressive_Matrices
- IQ classification. Wikipedia. en.wikipedia.org/wiki/IQ_classification
- About us. Mensa International. www.mensa.org/mensa/about-us
- IQ tests. British Mensa. www.mensa.org.uk/iq-tests
- Intelligence quotient. Wikipedia. en.wikipedia.org/wiki/Intelligence_quotient
- Fluid and crystallized intelligence. Wikipedia. en.wikipedia.org/wiki/Fluid_and_crystallized_intelligence
- Pearson. Wechsler Adult Intelligence Scale, Fifth Edition (WAIS-5), product page. 2024. www.pearsonassessments.com/store/usassessments/en/Store/Professional-Assessments/Cognition-%26-Neuro/Wechsler-Adult-Intelligence-Scale-%7C-Fifth-Edition/p/P100071002.html
- Pearson. Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V), product page. 2014. www.pearsonassessments.com/store/usassessments/en/Store/Professional-Assessments/Cognition-%26-Neuro/Wechsler-Intelligence-Scale-for-Children-%7C-Fifth-Edition/p/100000771.html
- Roid, G. H. Stanford-Binet Intelligence Scales, Fifth Edition (SB5), PRO-ED product page. 2003. proedinc.com/products-13290.html
- Pearson. Raven's Progressive Matrices brochure (CPM, SPM, APM). 2014. www.pearsonassessments.com/content/dam/school/global/clinical/us/assets/ravens/ravens-brochure.pdf
- American Mensa. Admission testing. www.us.mensa.org/join/testing/