Stanford-Binet intelligence test

Alfred Binet and Théodore Simon designed their scale in France in 1905 to identify children who needed extra help at school. Lewis Terman at Stanford adapted it for American use in 1916, and that Stanford Revision popularised the idea of an intelligence quotient.

The SB5 tests five factors, and each is tested twice, once with words and once without. The nonverbal route makes it usable for people with limited language, and it lets the examiner compare verbal and nonverbal performance. The two sets of five subtests give a Verbal IQ and a Nonverbal IQ, and together a Full Scale IQ. Two subtests, Object Series/Matrices and Vocabulary, act as routing tests that set the starting level for the rest, which is how the test adapts to the person.

In the early editions, IQ was literally a ratio: mental age divided by chronological age, multiplied by 100. A 10-year-old who performed like a typical 12-year-old had an IQ of 12 ÷ 10 × 100 = 120.

The ratio worked for children and failed for adults, because mental age stops rising in adulthood, so the formula would drop the IQ of everyone as they got older. Later editions replaced it with a deviation IQ, which compares a person with others of the same age and sets the average at 100 by definition. That is the approach every modern IQ test uses.

The Stanford-Binet editions from 1960 to 1986 defined the spread of scores with a standard deviation of 16 points. The SB5 uses 15, like the Wechsler tests. A score of 116 on the older scale is one standard deviation above average, and so is 115 on the newer one.

That is why American Mensa lists 132 for the old Stanford-Binet and 130 for the SB5. Both are two standard deviations above average (see standard deviation in IQ). To convert an older score to the 15-point scale, subtract 100, multiply by 15/16, and add 100 back.

The SB5 is an individually administered test with printed materials and a trained examiner who records responses. It is not offered as a self-service website test to the public. Sites that advertise the "only accredited online Stanford-Binet" or similar claim a link to the test that we could not verify, and their scores have no connection to the publisher's norms.

If you need a genuine result, for a school, a diagnosis or a society, find a psychologist who is qualified to give the SB5 or another test such as the WAIS. If you only want a rough look at your reasoning, an online reasoning test can give one, as long as you treat the number as an estimate. The LifeScore test is built from matrix-style visual puzzles, which resemble the SB5 nonverbal fluid reasoning subtest only. It does not test vocabulary, quantitative reasoning or memory, and it is not the Stanford-Binet.

The SB5 includes a nonverbal fluid reasoning factor, which uses pattern and matrix tasks. Here are three original items in that spirit.