About the 1916 Stanford-Binet
The Stanford-Binet Intelligence Scale (1916) was Lewis Terman's Stanford University revision of the French Binet-Simon scale, and it was the test that popularized the IQ formula (mental age divided by chronological age times 100) in the United States. It became the standard individual intelligence test in America and survives today as the Stanford-Binet Fifth Edition (SB5, 2003).
Lewis Terman's 1916 Stanford Revision of the Binet-Simon scale is the most important single document in the history of IQ testing. It is the book that:
- Coined the term IQ as a number. Before Terman, IQ was a ratio expressed as a decimal (mental age / chronological age). Terman multiplied by 100 to produce an integer, which became the convention every IQ test has used since.
- Established the 100-point average. Terman set the mean IQ of his Californian standardization sample to 100, defining the convention every modern test still uses.
- Made cognitive testing into a profession. The 1916 manual was the first comprehensive guide to administering and scoring an individual IQ test. It made the field operationally reproducible.
The test is age-graded: items are grouped by the age at which the average child can pass them. A child takes items at increasing age levels until they consistently fail; their mental age is calculated from how many items they passed at each level. The 1916 scale runs from Year III (age 3) through Year XIV, with an Average Adult and Superior Adult level above that.
Age levels included
Items are presented in order of difficulty, grouped by Terman's age-level system. Each item passed earns a fractional credit (in months) toward your mental age, per the original 1916 scoring rules.
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Each item has a brief instruction and a way to answer. There is no overall time limit, but the original test typically took 30-60 minutes. You can pause anytime.
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How Terman's mental age + IQ formula works
The 1916 Stanford-Binet computes mental age by adding up credits earned at each age level. The original 1916 rules:
- Start at the level below the subject's chronological age.
- Move down until you find a level where the subject passes ALL items - that is the basal age, which earns full credit.
- From the basal age upward, give partial credit for each individual item passed. The credit-per-item is fixed per level (e.g. 2 months per item at Year III, 3 months at Year XII, 4 months at Year XIV).
- Move up until you find a level where the subject fails ALL items - that is the ceiling age, beyond which no credit accumulates.
- Mental age (in months) = basal age in months + sum of all per-item credits.
Then IQ = (mental age / chronological age) × 100. So an 8-year-old (96 months) with a mental age of 108 months has an IQ of (108/96) × 100 = 112.
This is the ratio IQ formula. Modern tests (since Wechsler 1939) abandoned it for the deviation IQ: instead of comparing mental age to chronological age, modern tests compare your score to the distribution of scores in your age group, with the mean fixed at 100 and standard deviation at 15.
Take the full 84-item test
Stanford-Binet 1916: Verbal Subset (Interactive). 90+ items spanning age levels III through Superior Adult. Items adapted for self-administered multiple-choice from Terman's original (1916) age-credit format. Public domain.
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Read the Original
The following are legitimate free or borrowable full-text sources for this test or its primary documentation:
Source and verification
All items, instructions, and scoring criteria on this page are transcribed from:
Terman, L. M. (1916). The Measurement of Intelligence: An Explanation of and a Complete Guide for the Use of the Stanford Revision and Extension of the Binet-Simon Intelligence Scale. Boston: Houghton Mifflin Company. 362 pp.
This work is in the public domain in the United States (published before 1929). The full book is available on Internet Archive: archive.org/details/measurementofint1916term.
Items requiring physical materials, motor tasks, examiner judgment, or audio playback were excluded from this interactive version. A full list of skipped items is shown in the test interface.
Frequently asked questions
What is the Stanford-Binet Intelligence Scale (1916)?
The Stanford-Binet Intelligence Scale of 1916 is an individually administered intelligence test created by psychologist Lewis Terman at Stanford University. It was an American revision and expansion of the French Binet-Simon scale developed by Alfred Binet and Theodore Simon. The 1916 version standardized the test on American children, added new items, and introduced the intelligence quotient (IQ) to the United States. It quickly became the leading individual intelligence test in America for several decades.
Who created the 1916 Stanford-Binet, and why is it called Stanford-Binet?
It was created by Lewis M. Terman, a psychologist at Stanford University, which is why the test combines Stanford (Terman's institution) with Binet (Alfred Binet, who built the original 1905 Binet-Simon scale). Terman did not invent the scale from scratch. He adapted, re-standardized, and extended Binet and Simon's French test for use with English-speaking American populations, publishing the result in 1916.
What did the 1916 Stanford-Binet introduce to IQ testing?
The 1916 Stanford-Binet popularized the intelligence quotient (IQ) in the United States using the ratio formula: mental age divided by chronological age, multiplied by 100. A child whose mental age matched their chronological age scored 100, which fixed the average, or mean, at 100. This made test results comparable across ages and gave the concept of IQ the form most people still recognize today. The ratio IQ method was later replaced by deviation IQ scoring in modern editions.
What does the Stanford-Binet measure and how is it scored?
The Stanford-Binet measures cognitive ability, originally producing a single overall IQ score. The 1916 edition used a ratio IQ (mental age divided by chronological age times 100, with a mean of 100). Modern editions measure several factors, including fluid reasoning, knowledge, quantitative reasoning, visual-spatial processing, and working memory, across both verbal and nonverbal tasks, and report a deviation IQ where 100 is average and most scores fall between 85 and 115.
Is the Stanford-Binet still used today?
Yes. While the original 1916 edition is historical and no longer administered, the test has been revised repeatedly and is currently in its fifth edition, the Stanford-Binet Intelligence Scales, Fifth Edition (SB5), published in 2003. The SB5 remains one of the two dominant individually administered IQ tests in clinical and educational settings, alongside the Wechsler Adult Intelligence Scale (WAIS). It is widely used to assess intellectual ability, identify giftedness, and evaluate developmental and learning concerns.
How does the modern Stanford-Binet differ from the 1916 version?
The 1916 Stanford-Binet produced a single ratio IQ based on mental age and was designed primarily for children. The modern Stanford-Binet Fifth Edition (SB5, 2003) uses deviation IQ scoring rather than the mental-age ratio, covers ages 2 through adulthood, and breaks ability into five cognitive factors tested in both verbal and nonverbal domains. It also rests on far larger, more representative standardization samples than Terman's original 1916 norms.
Cite this page
This page is part of the Historical IQ Tests Archive. Editorial content, transcription notes, and curation are released under Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0). Public-domain primary sources retain their public-domain status. BibTeX · RIS
Historical test materials are obsolete and are not valid modern IQ assessments. This page is preserved for educational, research, and historiographic purposes.