How to Interpret Your IQ Score

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IQ (or intelligence quotient) exams have been around for about 100 years, in various forms. Today, they are given in schools to see if children are gifted or have other special needs, and by businesses and other employers. You can also find ‘do-it-yourself’ IQ tests online, if you are curious what your score is.

But once you get a score, what does that number truly mean? How do tests that purport to measure intelligence work, and do the scores actually reflect your brain power? How does your IQ test score compare with that of others taking such tests?

IQ Score Ranges and What They Mean

Most of the widely used IQ tests today try to measure key abilities, such as language, math ability, spatial ability, and others. They also test for logic, abstract reasoning, learning ability, and how well you retain information.

Common IQ tests, such as the Wechsler Adult Intelligence Scale and the Stanford-Binet Intelligence Scales, use a scoring method based on comparisons of your score to other people of your same gender and age. These scores fall along a bell-type curve, with most people scoring in the middle and much smaller percentages of test-takers scoring in the high and low ends. Only about 2% of people are classified in the highest IQ category, for example.

Here is a typical IQ test score range. Keep in mind these numbers may differ slightly depending on which test you take.

  • 130 and up: Very gifted
  • 120 - 129: Gifted
  • 111 - 119: Above-average intelligence
  • 90 - 109: Average intelligence
  • 80 - 89: Low-average intelligence
  • 70 - 79: Borderline intelligence
  • 69 and below: Extremely low intelligence

Another IQ test places 85 to 115 as the average range, with 145 as the start of high IQ and 160 or higher as "genius-level."

The American Psychiatric Association has developed the following ranges for very low IQ scores, to reflect level of disability:

  • 71 - 84: Borderline intellectual functioning
  • 50 - 55 to about 70: Mild mental retardation
  • 35 - 50 to 50 - 55: Moderate retardation
  • 20 - 25 to 35 - 40: Severe mental retardation
  • Below 20 - 25: Profound mental retardation

Does Your IQ Test Score Define You?

Experts who study intelligence say no. In fact, they say, a single test score on its own, without considering socioeconomic, genetic and other factors, should not be used to make determinations about people. You may be feeling ill the day you took the test; you may not have understood all the questions due to language difficulties (if English isn't your first language); or you may suffer from test anxiety.

Another concern is that IQ tests don't capture many of the traits that make a person successful. While having a very high IQ might allow you to think more quickly than most, this skill doesn't necessarily mean you can pick winning stocks, sell products to reluctant customers, make more friends, or achieve in any of a number of other ways.

It also does not make you a good person. One of the highest IQs ever recorded was 210 by Nathan Leopold, a wealthy Chicago college student who gained fame in 1924 for (along with friend Richard Loeb) killing a 14-year-old boy for an "intellectual thrill." Similarly, "Unabomber" Ted Kaczynski scored 167 as a young math prodigy, entered Harvard at 15 and went on to kill three people and injure 23 others.

Some researchers say IQ tests fail at their premise; that traditional conceptions of intelligence don't include all the ways we are smart. Researcher Howard Gardner, who recently retired from the Harvard Graduate School of Education, theorized there are multiple intelligences, most of which aren't assessed in typical IQ tests. These intelligences include mathematical, verbal, visual-spatial, physiological, naturalistic, self-reflective, social and musical aptitudes. Other theorists say EQ, or emotional intelligence is as important to success as IQ.

While IQ is associated with genetics—identical twins separated at birth share similar IQ scores, for example—it also isn't a fixed trait. Studies indicate a person can increase their intelligence through education (up to 5 IQ points for every year of learning), better nutrition, and exercise. Some brain-training programs may also raise intelligence. Attitude and motivation can make a difference as well, with research showing that thinking you are smart can help you score better, and that giving someone a monetary reward for a higher score can raise it as much as 20 points.

IQ scores already have been rising, going up worldwide about three points for every decade, starting in the latter part of the 20th century. Some researchers attribute this to improved nutrition; others to gains children have made at solving the kinds of problems these tests pose. However, the researcher who discovered the phenomenon, New Zealand philosopher James Flynn, believes one key factor is lower birth rate, which allows adults to give more attention to their infants.

Going forward, researchers also are studying raising IQ scores through medications (nootropics), with different ones given at different stages of life to keep our brains sharp. Perhaps one day, all you will need to achieve a higher IQ test score is to take a pill.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Oct 12
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