Stanford-Binet Intelligence Scales, Fifth Edition (SB5)

Where the Stanford-Binet comes from

The Stanford-Binet is the direct descendant of the first practical intelligence test. Alfred Binet and Theodore Simon published that test in 1905, and Lewis Terman published the Stanford revision in 1916 (Wikipedia: Intelligence quotient). Terman's long-running study of children with high ability enrolled 1,470 California children with a Stanford-Binet IQ of 135 or above, plus 58 siblings (Terman Life-Cycle Study (Maelstrom)). The fifth edition, by Gale Roid, was published in 2003 (Wikipedia: Stanford-Binet).

What the SB5 measures

PRO-ED lists five factors, organized into two domains, Verbal and Nonverbal (PRO-ED: SB5):

The Fluid Reasoning and Knowledge factors echo the distinction Raymond Cattell drew in 1963 between reasoning with novel material and acquired knowledge (Wikipedia: Fluid and crystallized intelligence), covered in fluid vs crystallized intelligence.

Format and timing

The SB5 covers ages 2 to 85 and older and is administered individually (PRO-ED: SB5). PRO-ED says testing takes approximately 5 minutes for each of its 10 subtests (PRO-ED: SB5). Because of that wide age range, the same test can be used with a preschooler and with an older adult, each compared with their own age group.

Scoring and norms

SB5 composite scores have a mean of 100 and a standard deviation of 15, with a range of 40 to 160. The norms come from 4,800 people between ages 2 and 85 and older (PRO-ED: SB5). On that scale, 130 is two standard deviations above the mean, higher than about 97.7% of same-age people, and 145 is about 1 in 740.

Older Stanford-Binet forms used a standard deviation of 16, so the same percentile printed as a different number (Wikipedia: IQ classification). If you are comparing an old report with a new one, convert both to percentiles first. The percentile-to-IQ converter handles SD 15 and SD 16.

Who uses it

PRO-ED describes the SB5 as a major instrument for assessing intellectual giftedness (PRO-ED: SB5). Its ceiling of 160 gives room at the top. American Mensa lists an IQ of 130 on the Stanford-Binet 5 among its qualifying scores (American Mensa: qualifying scores).

SB5 compared with the Wechsler tests

Both report deviation IQ scores with a mean of 100 and SD 15, an approach David Wechsler introduced in 1939 (Wikipedia: WAIS). The main practical difference is coverage: the Wechsler line uses three tests for three age groups, while the SB5 spans ages 2 to 85 and older on its own. The WAIS-5 page and the IQ tests compared guide set them side by side.

Practicing the kinds of reasoning involved

SB5 items are not public. If you want to try fluid and quantitative reasoning with original items, our number sequence test and matrix puzzles are free. They are not Stanford-Binet items, and no IQ Octopus score predicts an SB5 score.

IQ Octopus is not affiliated with or endorsed by PRO-ED or any other publisher named here. Test names are used only to identify and describe the tests. Our free practice tests are not copies of any published test, and no score on IQ Octopus predicts a score on another test.