What is the formula to calculate IQ? Is IQ of 100 good?

What is it:

Intelligence. It allows a person to succeed in life. It is one of the things that differentiate humanity from any other type of animal on our planet. It is believed that the more intelligent a person is, the more successful they will be in their life. But what is intelligence? It is a rather abstract concept after all. The system of scoring intelligence, called the Intelligence Quotient, or IQ, aims to quantify this unclear concept.

This test, and the convention of calling the intelligence a person has IQ, became popular roughly a hundred years ago in 1916. Stanford University psychologist Lewis Terman invented a formula to numerically measure the intelligence of a person. This formula was revised several times, in 1937, 1960, and the last time in 1972 in attempts to more accurately gauge a person’s intelligence. The formula is as follows:

IQ = (Mental Age ÷ Physical Age) x 100

Physical age’s meaning is quite clear. If a person taking the IQ test is 10 years old, then their physical age is 10 for the purpose of the test. Mental age is a little harder to quantify. It relies on a lot of data regarding what types of things people of certain ages should know. So, if a 10-year-old is able to answer questions that the average 13-year-old should know, they show advanced ability for their age. Thus, their mental age in the formula would be considered 13. The formula would work out like this:

IQ = (13 ÷ 10) x 100

IQ = 130

The child in the equation above would be fairly intelligent by any stretch of the definition. Conversely, if a 10-year-old can only answer questions that the average 8-year-old would be able to answer, then the formula would work out like this:

IQ = (8 ÷ 10) x 100

IQ = 80

This would show that the child is below average in terms of raw intelligence, at least according to this test. Finally, if the child can only answer questions the average 10-year-old would be able to answer, then his or her IQ would be 100, a perfect average. Thus, a person that scores a 100 on an IQ test is not traditionally intelligent, merely average, as the test’s formula shows.

One factor to consider with this test is that the questions asked need to be designed in such as way to test the intelligent, logical centers of the brain. Questions that rely on knowledge only obtained through a formal education would be skewed towards those who have the means to support such an education. Even in today’s world, not everyone gets a good education. Therefore, questions that rely on pure reasoning and logical skills (skills every intelligent person would have) are better to use for IQ tests. That being said, skills like critical thinking or logical processes learned in math would be very useful on an IQ test. Because of this, an IQ test will likely never be truly empirical about how intelligent a person actually is. 

True intelligence cannot be truly measured. There are far more factors than can be accounted for. Just because a person does not score highly on an IQ test does not mean they are stupid or will not succeed. A good example of this is a student who does well in school but fails to perform on standardized tests. The student is very competent, except within the strict bonds of a standardized test. Their failure does not prove their stupidity, rather that the testing method is flawed.

If you do take an IQ test, what constitutes a good score? Generally, anything above a score of 140 is considered near genius, or genius level intelligence. Anything below 70, the person in question likely has a mental disability affecting their reasoning and processing skills.

Historical Geniuses:

Albert Einstein – 160

Isaac Newton – 190

Marie Curie – 185

Shakespeare – 210

Steve Jobs – 178

As you can see from these numbers, while, yes, these smart people all scored very highly, they may not have scored as high as you think they would have. Part of this has to do with they were not alive to take the test. The numbers are based off what we know of them as people, especially things regarding their formative years. IQ tests cannot truly, accurately, give a picture of how smart a person is, but rather they give a general base knowledge of a person’s logical and intellectual skills they possess at the time.

IQ in culture:

Much of a person’s intellectual development occurs early in their formative years. There is much evidence that shows the more a person’s brain is stimulated, the better chance they have of succeeding. After all, the brain is a muscle.