IQ 74: why the test version matters
An IQ of 74 is higher than about 4.2% of people, roughly 1 in 24 at or below, in the borderline or "very low" range. In the 70s, a detail most people never think about can matter a lot: how old the test's norms were when the score was worked out.
74 on the IQ bell curve
An IQ of 74 is 26 points below the average of 100, or 1.73 standard deviations. About 4.2% of people of the same age score lower, the shaded sliver at the far left of the curve below.
On a test with a standard deviation of 16, such as older Stanford-Binet editions, the same result would be about 72, and on the Cattell scale, which uses 24, about 58. Why scales differ.
Reading an IQ of 74
IQ scores are calculated against a norm group tested when the test was built. Through most of the 20th century, average performance on IQ tests rose by about 3 points per decade, a finding confirmed by a 2015 analysis of nearly 4 million people. A test normed 20 years earlier compares you with a lower-scoring generation, so it can make the same performance look about 6 points higher.
That is why psychologists, and courts in intellectual disability cases, ask which edition of a test was used and when it was normed. A 74 on an up-to-date test and an 80 on an outdated one can describe the same person. If you are comparing your own scores from different years, check the test names before worrying about the gap.
How an IQ of 74 is classified
Different tests and manuals use different words for the same score, and the words have changed over time. Here is where 74 falls on each of the systems you are most likely to meet.
Sources: American Psychiatric Association, DSM-5 fact sheet on intellectual disability; World Health Organization, ICD-11, 6A00 disorders of intellectual development; Peltopuro, M. and others (2014), "Borderline intellectual functioning: a systematic literature review", Intellectual and Developmental Disabilities, 52(6), 419–443. WISC-V descriptors from Pearson's interpretive reports, as on our good IQ score guide.
When is 74 part of an intellectual disability?
A score of 74 on its own never makes a diagnosis. The American Psychiatric Association's DSM-5 describes intellectual disability as "approximately two standard deviations or more below the population, which equals an IQ score of about 70 or below", and requires three things together:
- Low intellectual functioning, confirmed by a clinical assessment and individually given, standardised testing.
- Difficulties with everyday adaptive skills in at least one of three domains: conceptual (language, reading, maths, memory), social (communication, judgement, friendships) and practical (personal care, money, work and school tasks).
- A start during the developmental period, in childhood or adolescence.
Severity is set by those everyday skills, not by the IQ number. That is why only about 1% of people have an intellectual disability (a 2011 meta-analysis of 52 population studies found about 10 per 1,000), even though about 2.3% score below 70 on the bell curve. Because tests have a margin of error, DSM-5 treats roughly 65 to 75 as the uncertain zone around 70, and 74 is inside it.
Sources: American Psychiatric Association, DSM-5 fact sheet on intellectual disability; Maulik, P. K. and others (2011), "Prevalence of intellectual disability: a meta-analysis of population-based studies", Research in Developmental Disabilities, 32(2), 419–436; Hall v. Florida, 572 U.S. 701 (2014), which cites the DSM-5 range of 65 to 75.
Borderline intellectual functioning and an IQ of 74
Scores from roughly 70 to 85 are often described as borderline intellectual functioning. It is not a diagnosis of intellectual disability: most people in this range live independently, work and raise families. But a 2014 systematic review of 49 studies found that the group faces more neurocognitive, social and mental health difficulties than average, and called it "almost invisible" in research and services.
On a perfect bell curve, about 13.6% of people score between 70 and 85, so this is far from rare. People in the range often learn best with clear, concrete instructions, worked examples and extra time for new or written tasks, and often do well in practical, hands-on work.
Source: Peltopuro, M. and others (2014), "Borderline intellectual functioning: a systematic literature review", Intellectual and Developmental Disabilities, 52(6), 419–443.
Why scores near 70 matter in US courts
In Atkins v. Virginia (2002), the US Supreme Court ruled that executing a person with an intellectual disability is unconstitutional, and left states to decide who qualifies. In Hall v. Florida (2014) it struck down a rule that treated 70 as a strict cut-off, because every test has a margin of error. In Moore v. Texas (2017) it said courts must be guided by current medical standards rather than "lay stereotypes".
The practical lesson is the same outside a courtroom: a score of 74 is best read as a range, about 69 to 79, and judged alongside how a person actually manages daily life.
Sources: Atkins v. Virginia, 536 U.S. 304 (2002); Hall v. Florida, 572 U.S. 701 (2014); Moore v. Texas, 581 U.S. 1 (2017).
Before you trust a 74
Low scores are the most fragile results on any test, because almost everything that goes wrong on the day pulls a score down. Common reasons include:
- Running out of time. On timed tests, including ours, an unanswered question counts as wrong.
- Nerves. A review of 238 studies found test anxiety consistently linked with lower scores.
- Tiredness. Sleep loss hits attention and speed hardest, which costs points against the clock.
- Language and format. Taking a test in a second language, on a small screen or in an unfamiliar format can lower a result without saying anything about reasoning.
What a 74 means on our test
The Assessivo test moves in steps of about 2.5 points, so it can't give exactly 74: the nearest results are 73 (7 correct) and 75 (8 correct). Every question has four options, so someone guessing every answer at random averages nine correct, a score of 78. That is within what pure guessing produces: a guesser lands at or below this level in about 29% of attempts. Read it as "not measured yet" rather than a verdict, and retake the test rested, with time to spare.
If any of this sounds like your session, retake the free IQ test when you are rested and have 25 quiet minutes. A score that moves a lot between attempts was never very solid.
Sources: von der Embse, N. and others (2018), "Test anxiety effects, predictors, and correlates: a 30-year meta-analytic review", Journal of Affective Disorders, 227, 483–493; Lim, J. and Dinges, D. F. (2010), "A meta-analysis of the impact of short-term sleep deprivation on cognitive variables", Psychological Bulletin, 136(3), 375–389. Guessing figures are worked out from the binomial distribution for 36 four-option questions.
What is the mental age for an IQ of 74?
The first IQ tests, for children, described performance as a "mental age": the age whose typical performance a child matched. IQ was mental age divided by real age, times 100. Run that old formula backwards and you get the figures below, for children only.
| Child's age | Performs like a typical child of about |
|---|---|
| 6 | 4 years 5 months |
| 8 | 5 years 11 months |
| 10 | 7 years 5 months |
| 12 | 8 years 11 months |
| 14 | 10 years 4 months |
For adults the idea doesn't work, which is why David Wechsler replaced it in 1939 with today's method: compare each person with others of the same age. An adult who scores 74 has an adult's knowledge, interests and experience. The score only says how their test performance compares with other adults'.
How common is an IQ of 74?
Line up 100 people of the same age and about 4 would score 74 or lower; the orange dot marks the place. In a school of 1,000 pupils, you would expect about 42 at or below this level.
The bar shows the likely range on a professional test, about five points either way: 69 to 79, from the 2nd to the 8th percentile.
How 74 compares with nearby scores
| IQ | Percentile | Classic label | Score this low or lower |
|---|---|---|---|
| 64 | 0.82th | Extremely low | 1 in 122 |
| 69 | 2nd | Extremely low | 1 in 52 |
| 74 | 4th | Borderline | 1 in 24 |
| 79 | 8th | Borderline | 1 in 12 |
| 84 | 14th | Low average | 1 in 7 |
Questions about an IQ of 74
What percentile is an IQ of 74?
An IQ of 74 is at about the 4th percentile: it is higher than about 4.2% of people of the same age, and roughly 1 person in 24 scores this low or lower.
Is 74 a low IQ?
Yes. 74 is 26 points, or 1.73 standard deviations, below the average of 100. On the classic Wechsler labels it is borderline, and the current children's Wechsler test calls it very low. A single score is an estimate with a margin of error of about five points, so 74 is best read as roughly 69 to 79.
Is 74 IQ an intellectual disability?
Not on its own. 74 is just above 70, inside the margin of error that clinicians allow around it, so a diagnosis would depend on whether there are significant difficulties with everyday skills that began in childhood.
What is the mental age for an IQ of 74?
Mental age is an idea from the earliest tests for children. By the old formula, a 10-year-old scoring 74 would perform like a typical child of about 7 years 5 months. For adults it has no meaning: modern IQ tests compare adults with other adults, and an adult who scores 74 is not like a child.
Why did I get different IQ scores on different tests?
Tests differ in their questions, their scales and the age of their norms. Because average scores rose by about 3 points per decade for much of the 20th century, a test with old norms can give a higher number for the same performance. Every score also has a margin of error of about five points.
Related: the IQ range chart, what counts as an average IQ, what IQ measures and misses and how to tell if an online IQ test is accurate.
An IQ test arrives at a score like 74 by combining several kinds of task. Learn more about processing speed, fluid vs crystallized intelligence, abstract reasoning, spatial reasoning and verbal reasoning, or try the free pattern recognition test.
Information and support
If a professional assessment has given you, your child or someone you care for a score like 74, these organisations explain what it means in practice and what help is available.
Want a second reading?
Take the free Assessivo IQ test when you are rested and have 25 quiet minutes: 36 questions, and your estimated score and percentile as soon as you finish.
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