Test types
The Stanford–Binet
A direct descendant of the first practical intelligence scale, still in print after more than a century and still used where the Wechsler tests run out of range.
Where it comes from
Alfred Binet and Théodore Simon published the first practical intelligence scale in Paris in 1905, built to identify schoolchildren who needed additional support.
Lewis Terman at Stanford revised and renormed it on American children in 1916, producing the Stanford–Binet. It dominated intelligence testing for decades and is currently in its fifth edition.
The history is worth knowing because Terman changed the purpose as well as the norms. Binet built a tool to direct help towards struggling children and warned explicitly against treating the scale as a measure of fixed capacity. Terman treated it as exactly that. The longer history.
What the fifth edition measures
SB5 assesses five factors, each in both a verbal and a non-verbal mode — ten subtest areas in total.
| Factor | What it covers |
|---|---|
| Fluid reasoning | Solving novel problems without a learned method |
| Knowledge | Accumulated information, vocabulary, general learning |
| Quantitative reasoning | Reasoning about number and quantity |
| Visual–spatial processing | Spatial relations, patterns, construction |
| Working memory | Holding and manipulating information briefly |
Splitting every factor into verbal and non-verbal versions is the test's distinguishing feature. It allows a meaningful assessment of someone with limited expressive language, a hearing impairment or a different first language, without abandoning the factor structure.
How it differs from the Wechsler tests
The two are more alike than different, and the differences matter in specific cases.
- Age range. SB5 covers two to eighty-five and over in a single instrument. The Wechsler family splits the same span across WPPSI, WISC and WAIS.
- Range at the extremes. SB5 is generally regarded as having better measurement at the low end and more headroom at the high end, which is why it is often the instrument chosen for assessments near either tail.
- Verbal and non-verbal parity. Every factor exists in both modes, which the Wechsler structure does not provide.
- Routing. SB5 uses routing subtests to determine the starting level, which shortens administration.
Both use a mean of 100 and a standard deviation of 15 in their modern editions. Older Stanford–Binet forms used 16, which is the source of some of the mismatched historical figures that circulate.
Early Stanford–Binet editions used the mental-age ratio. A child of five performing like a ten-year-old scored 200. Those numbers are not comparable to a modern deviation score and are the origin of most of the extraordinary childhood IQ figures that appear in popular writing.
When it is used
Assessment of young children, where the age range and routing structure suit. Cases at either extreme of the range, where the Wechsler tests have less measurement precision. Assessment where a verbal–non-verbal comparison within the same factor is clinically useful. And as an approved instrument for high-IQ society entry, including Mensa in several countries.
Like the WAIS and the WISC, it is administered individually by a qualified professional over one to two hours, and it is not available in any online form.
Questions
Questions people ask
What is the Stanford–Binet test?
An individually administered intelligence test descended from Binet and Simon's 1905 scale, revised by Lewis Terman at Stanford in 1916 and currently in its fifth edition.
What does the Stanford–Binet measure?
Five factors — fluid reasoning, knowledge, quantitative reasoning, visual–spatial processing and working memory — each assessed in both verbal and non-verbal modes.
Is the Stanford–Binet better than the WAIS?
Neither is better in general. SB5 covers a wider age range in one instrument and has more measurement precision at the extremes; the Wechsler tests are more widely used for routine adult assessment.
Why do old Stanford–Binet scores look so high?
Early editions used the mental-age ratio, which produces very large numbers for precocious children. Those figures are not comparable to modern deviation scores.
Does Mensa accept Stanford–Binet results?
It appears on the approved list in several countries, provided the administration was properly supervised and documented.
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