One of the main factors to take into account when looking at an IQ score is the age of the person that has taken the test. IQ scale: IQ charts by age. Different scores mean different things depending on age.
Even though there are many IQ tests available, they all use the same scale. Originally, the whole notion of IQ was arrived by the American psychologist and author Lewis Terman. Terman did not only devised the original IQ tests but also the scale used to classify all the different scores.
The IQ Scale
Although the scale for IQ scores can have slightly different names, it is always the same otherwise. Here is the original classification according to Terman:
Any IQ scores under 70 are classified as being “definite feeble-mindedness” or “low.” Scores between 70 and 79, indicate a “borderline deficiency” or “borderline low.” Those scores between 80 and 89 are indicative of “dullness” or “lower average.”
But scores between 90 and 109 indicate a “normal or average intelligence” or “higher average.” While scores between 110 and 119 are indicative of a “superior intelligence” or “above average.” Anyone scoring between 120 and 140 in their IQ test would be classified as having a “superior intelligence” or being “gifted.” The highest possible scores are those over 140, which indicates “genius or nearly genius.”
“We have seen that intellect and achievement are far from perfectly correlated.” — Lewis Terman
How are IQ Scores Distributed?
What follows is a very general estimation of the percentage of the population that fits into one of the categories that we have gone over.
Let us begin with the lowest scores. It is estimated that about 0.13% of people score low. About 2.14% of people score borderline low. 13.59% of people score below average, and 34.13% lower average.
Now let us look at the higher scores on the IQ scale. It is estimated that also about 34.13% of people have a higher average score. 13.59% of people have an above-average score. Only 2.14% of people attain a gifted score, while a tiny 0.13% of people can be classified under genius status.
People with a growth mindset believe that they can improve with effort. They outperform those with a fixed mindset, even when they have a lower IQ, because they embrace challenges, treating them as opportunities to learn something new. – Travis Bradberry
How Accurate Is The Data?
Although scores by age or nationality should always be taken with a pinch of salt it may be useful to look at them under certain circumstances.
There is no actual data organized by age, but there is some information about age groups. The following information should only be used for entertainment purposes, as it may not be totally accurate or the information may be out of date.
“If we encounter a man of rare intellect, we should ask him what books he reads.” ― Ralph Waldo Emerson
There is only data for people between the ages of 16 and 74. This is mostly because IQ tests are not recommended for younger children unless individually recommended and guided by a psychologist.
Having said all of that, here are the average scores on the IQ scale for each age group.
Average IQ For Each Age Group
It is estimated that the average score for 16 to 17-year-olds is 108, which denotes “normal or average intelligence.”
For adults between 18 and 19 years of age, the average IQ score is 105, which also denotes “normal or average intelligence.”
The average score for people between 20 and 24 years of age is 99, which also denotes “normal or average intelligence.”
For people between 24 and 34 years of age, the average score is slightly lower at 97, which still denotes “normal or average intelligence.”
The scores begin to go up again after that age, among older adults. For example, the average score for people between 35 and 44 years old is estimated to be 101, still within the “normal or average intelligence” scale.
If we don’t plant the right things, we will reap the wrong things. It goes without saying. And you don’t have to be, you know, a brilliant biochemist and you don’t have to have an IQ of 150. Just common sense tells you to be kind, ninny, fool. Be kind. – Maya Angelou
And for people between the ages of 45 and 54, the average IQ score goes up to 106 within the “normal or average intelligence” scale. But the highest average score for people under 64 is attained by those people between the ages of 55 and 64, which gets to 109 in the IQ scale, just about falling short of being classed as having a “superior intelligence” or “above average” intelligence and remaining firmly within the limits of a “normal or average intelligence” like all the other age groups.
Both age groups over 65 get a higher score. People between 65 and 69 have an average IQ score of 114, which puts them in the “superior intelligence” or “above average” end of the scale. But people between 70 and 74 who are tested for IQ get an even higher average score of 119, which puts them a mere 1 put short of getting into the “gifted” category, which means that they are still firmly within the “above average” or “superior intelligence” group together with their younger 65-69 years old counterparts.
It should not be a surprise to anyone that all age groups that have been tested always attain an average score since, as we have already seen, overall, most people who get their IQ tested get scores within that scale.
What Is the Normal Distribution of IQ Scores?
If you do not take age into account, you can look more globally at IQ scores.
For example, did you know that about 50 percent of IQ is between 90 and 110? Or that 70 percent have a score of between 85 and 115? These figures are surely illuminating. But, wait, it gets more interesting! About 95 percent of all IQ scores are between 70 and 130. And, the overwhelming majority of them (99.5 percent) do fall somewhere between 60 and 140.
Only the people who are in the highest 2 percent of the IQ scale can be admitted into Mensa, the largest and most prestigious high IQ society in the world, with members in most countries around the world.
IQ charts by age or any other criteria must be treated with the utmost care. One reason for that if that we must always ensure that we keep it scientific and that no prejudices whatsoever go into it. Also, there are many different tests available but only a small portion of people would actually take those tests. And then there is the issue of mortality that still varies considerably in different countries around the world.