What Is the Average IQ?

What does it really mean to have an average IQ score?

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What is the average IQ and what does it really mean to be of average intelligence? The measurement of intelligence has long been a hot topic in psychology and education—and a controversial one. IQ, or intelligence quotient, is a measure of your ability to reason and solve problems. It essentially reflects how well you did on a specific test as compared to other people of your age group.

While IQ can be a predictor of things such as academic success, experts caution that it is not necessarily a guarantee of life success.

Sometimes people with very high IQs do not fair so well in life, while those with average IQs may thrive.

What Is an Average IQ?

Intelligence tests are one of the most popular types of psychological tests in use today. Ever since the first IQ tests emerged, attempts to classify IQ have followed.

In order to understand what an average IQ score is and what it means, it is essential to first understand how IQ is measured. While different test publishers utilize different scoring systems, for many modern IQ tests the average (or mean) score is set at 100 with a standard deviation of 15 so that scores conform to a normal distribution curve.

  • On many tests, a score of 100 is considered the average IQ.
  • 68 percent of scores fall within one standard deviation of the mean (that is, between 85 and 115). That means that nearly 70 percent of all people score within plus or minus 15 points of the average score.
  • 95 percent of scores fall within two standard deviations (between 70 and 130). Outliers beyond those points represent only a small portion of the population, which means that only a small percentage of people have a very low IQ (below 70) or a very high IQ (above 130).
  • Scores below 70 may represent the presence of some sort of developmental or learning disability while scores over 130 may indicate giftedness.

    How Is the Average IQ Calculated?

    So why is the average score set to 100? Historically, IQ tests have been scored in one of two ways. In the first method, a person's mental age was divided by their chronological age and then multiplied by 100. The other methods involves, comparing scores against the scores of others in the individual's same age group.

    In this method, psychometricians utilize a process known as standardization to make it possible to compare and interpret the meaning of IQ scores. This process is accomplished by administering the test to a representative sample and using these scores to establish standards, usually referred to as norms, by which all individual scores can be compared. Since the median score is 100, experts can quickly assess individual test scores against the median to determine where these scores fall on the normal distribution.

    Classification systems can vary from one publisher to the next although many do tend to follow a fairly similar rating system.

    • For example, on the Wechsler Adult Intelligence Scale and the Stanford-Binet test, scores that fall between 90 and 109 are considered "Average." 
    • On these same tests, scores that fall between 110 and 119 are considered "High Average." Scores between 80 and 89 are classified as "Low Average."

      So in most cases, if you receive an IQ score of around 100, then you have what is considered an average IQ. Don't worry – you are in good company. Most people score within one standard deviation of this average.

      What Exactly Are IQ Tests Measuring?

      Intelligence tests are designed to measure crystallized and fluid intelligence. Crystallized intelligence involves your knowledge and skills you have acquired throughout your life while fluid intelligence is your ability to reason, problem-solve and make sense of abstract information.

      Fluid intelligence is considered independent of learning and tends to decline in later adulthood.

      Crystallized intelligence, on the other hand, is directly related to learning and experience and tends to increase as people grow older.

      IQ tests are administered by licensed psychologists. There are different kinds of intelligence tests, but many involve a series of subtests that are designed to measure mathematical abilities, language skills, memory, reasoning skills and information-processing speed. Scores on these subtests are then combined to form an overall IQ score.

      A few of the most common IQ tests in use today include:

      • The Wechsler Adult Intelligence Scale for Adults
      • The Wechsler Intelligence Scale for Children
      • The Stanford-Binet Intelligence Scales
      • The Kaufman Assessment Battery for Children
      • The Cognitive Assessment System
      • The Differential Ability Scales
      • The Woodcock-Johnson Tests of Cognitive Abilities

      It is important to note that while people often talk about average, low and genius IQs, there is no single IQ test. Many different tests are in use today including the Stanford-Binet, the Wechsler Adult Intelligence Scale and the Woodcock-Johnson Tests of Cognitive Abilities. Each individual test is different in terms of exactly what is being measured, how it is scored, and how these scores are interpreted.

      So What Does It Mean to Have an Average IQ?

      • It means you have average reasoning and problem-solving skills. Your IQ score might be a good general indicator of your reasoning and problem-solving abilities, but many psychologists suggest that these tests don't tell the whole story.
      • An average IQ score might not tell the whole story about what you are capable of. A few things they don't measure are practical skills and talents. You might have an average IQ score, but you might also be a great musician, a creative artist, an incredible singer or a mechanical whiz. Psychologist Howard Gardner developed a theory of multiple intelligences designed to address this perceived shortcoming in popular conceptions of IQ.
      • IQ scores are not necessarily set in stone. Researchers have also found that IQ scores can change over time. One study looked at the IQ's of teenage subjects during early adolescence and then again four years later. The results revealed that scores varied as much as 20 points over that four-year period.
      • Some experts suggest that EQ might matter even more than IQ. IQ tests also fail to address things like how curious you are about the world around you and how good you are at understanding and managing emotions. Some experts, including writer Daniel Goleman, suggest that emotional intelligence (often referred to as EQ) might even be more important than IQ. And researchers have found that while having a high IQ can indeed give people and edge in many areas of life, it is certainly no guarantee of life success.

      A Word From Verywell

      Don't stress out if you're not a genius—the vast majority of people aren't geniuses either. Instead, most people are somewhere within a 15 point range of the average IQ score.

      Just as having a high IQ doesn't ensure success, having an average or low IQ doesn't ensure failure or mediocrity. Other factors such as hard work, resilience, perseverance and overall attitude are important pieces of the puzzle.

      Sources:

      Ramsden, S., Richardson, F. M., Josse, G., Thomas, M. S. C., Ellis, C., Shakeshaft, C., Seghier, M. L., & Price, C. J. (2011).Verbal and non-verbal intelligence changes in the teenage brain. Nature, 479, 113-116.doi:10.1038/nature10514.

      Schaffer, DR & Kipp, K. Developmental Psychology: Childhood and Adolescence. Belmont, CA: Wadsworth; 2010.

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