What Is an IQ?

What is IQ?
Just What is and IQ?. Brand X Pictures/Getty Images

The measurement of intelligence is a contentious topic, and one that often sparks debate among educators and psychologists. Is intelligence even measurable, they ask? And if so, is its measurement important when it comes to predicting success and failure?

Some who study the relevance of intelligence claim that there are many types of intelligence, and maintain that one type is not necessarily better than another. Students who have a high degree of spatial intelligence and a lower degree of verbal intelligence, for instance, can be just as successful as anybody else. The differences have more to do with determination and confidence than one single intelligence factor.

But decades ago, leading educational psychologists came to accept the Intelligence Quotient (IQ) as the most acceptable single measuring stick for determining cognitive competence. So what is the IQ, anyway?

The IQ is a number that ranges from 0 to 200 (plus), and it is a ratio that is derived by comparing mental age to chronological age.

"Actually, the intelligence quotient is defined as 100 times the Mental Age (MA) divided by the Chronological Age (CA). IQ = 100 MA/CA"
From Geocities.com

One of the most notable proponents of the IQ is Linda S. Gottfredson, a scientist and educator who published a highly-regarded article in Scientific American. Gottfredson asserted that "Intelligence as measured by IQ tests is the single most effective predictor known of individual performance at school and on the job."

Another leading figure in the study of intelligence, Dr. Arthur Jensen, Professor Emeritus of educational psychology at the University of California, Berkeley, has created a chart that spells out the practical implications of various IQ scores. For instance, Jensen stated that people with scores from:

  • 89-100 would be employable as store clerks
  • 111-120 have the ability to become policemen and teachers
  • 121-125 should have the ability to excel as professors and managers
  • 125 and higher demonstrate skills necessary for eminent professors, executives, editors.

What Is a High IQ?

The average IQ is 100, so anything over 100 is higher than average. However, most models suggest that a genius IQ starts around 140. Opinions about what constitutes a high IQ actually vary from one professional to another.

Where Is IQ Measured?

IQ tests come in many forms and come with varied results. If you are interested in coming up with your own IQ score, you can choose from a number of free tests that are available online, or you can schedule a test with a professional educational psychologist.

Sources and Suggested Reading

  • Gottfredson, Linda S., “The General Intelligence Factor.” Scientific American November 1998. 27 June 2008.
  • Jensen, Arthur. Straight Talk About Mental Tests. New York: The Free Press, A Division of the Macmillan Publishing Co., Inc., 1981.
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Fleming, Grace. "What Is an IQ?" ThoughtCo, Aug. 25, 2020, thoughtco.com/what-is-an-iq-1857078. Fleming, Grace. (2020, August 25). What Is an IQ? Retrieved from https://www.thoughtco.com/what-is-an-iq-1857078 Fleming, Grace. "What Is an IQ?" ThoughtCo. https://www.thoughtco.com/what-is-an-iq-1857078 (accessed May 29, 2023).