Intelligence quotient (iq) is a measure of intelligence that takes into account an individuals

By Dr. Edwin van Thiel, updated February 18, 2019

In science, the term intelligence typically refers to what we could call academic or cognitive intelligence. In their book on intelligence, professors Resing and Drenth (2007)* answer the question 'What is intelligence?' using the following definition: "The whole of cognitive or intellectual abilities required to obtain knowledge, and to use that knowledge in a good way to solve problems that have a well described goal and structure."

In ordinary language, one could say that intelligence refers to how smart or clever you are.

The first intelligence tests used in the field of psychology

The scales designed by Binet and Simon were the first intelligent tests that became widely accepted at the beginning of the 20th century. The Alpha and Beta army tests, that were used in World war I to assess military personnel, became very popular.

In recent years, the Wechsler scales are the most widely used instruments in the field of psychology for measuring intelligence. The designer of these tests, Wechsler, published his first scale in the 1930s. He used material from the Binet Alpha and Beta tests to make his test. An important feature of his test was, that when calculating the IQ, this test took age into account. In other words, in the computation of the IQ, an age-correction takes place. Because of this feature, the IQ stays constant over the life span.

The Intelligence Quotient (IQ)

IQ is an acronym for Intelligence Quotient. So what is IQ? The IQ is a measurement of your intelligence and is expressed in a number.

A person's IQ can be calculated by having the person take an intelligence test. The average IQ is 100. If you achieve a score higher than 100, you are smarter than the average person, and a lower score means you are (somewhat) less smart.

An IQ tells you what your score is on a particular intelligence test, often compared to your age-group. The test has a mean score of 100 points and a standard deviation of 15 points. What does this standard deviation mean? It means that 68 percent of the population score an IQ within the interval 85-115. And that 95 percent of the population scores within the interval 70-130.

Some examples

What does it mean when your IQ is 100? That means that half of the population scores higher than you. The other half scores lower than you. And what does it mean when you have an IQ of 130? That means that 97,5 percent of your age group scores lower than you. Only 2,5 percent scores higher.

Take a look at a nice graph explaining more scores at meaning of an IQ score.

Further reading: Increasing your IQ and multiple intelligences. You can also take a free IQ test, or read the article on the history of the IQ test.

* Resing, W., & Drenth, P. (2007). Intelligence: knowing and measuring. Amsterdam: Publisher Nieuwezijds

Intelligence quotient, or IQ, a score that takes into account an individual’s mental and chronological ages. Historically, the first IQ scores employed the following formula, in which MA stands for mental age and CA for chronological age:

                                        IQ score = (MA/CA)100

Using this formula, we can return to the earlier example of a 20 year old performing at a mental age of 18 and calculate an IQ score of (18/20)*100 = 90. In contrast, the 5 year old performing at a mental age at 3 comes out with a considerable lower IQ score: (3/5)100=60.


Intelligence quotient means a score obtained from an intelligence test by dividing the mental age obtained on the test by the actual or chronological age and multiplying by 100, i.e. IQ=cA/ x 100. An IQ score by itself is meaningless; it does not measure intelligence the way a tape measures height, for instance. It is only a measure of comparison between all the people who have taken that particular test, with the average range of scores being placed arbitrarily around 100.

8 February 2021

Intelligence quotient (iq) is a measure of intelligence that takes into account an individuals

You have probably heard about IQ before. You may even have taken some free online quiz that promises to reveal how smart you are compared to Albert Einstein or Stephen Hawking.

So, exactly what is IQ?

How is it measured?

And does it matter?

What is IQ?

IQ stands for intelligence quotient and, in short, it is a measure of a person’s reasoning ability.

In other words, an IQ test is supposed to gauge how well someone can use information and logic to answer questions or make predictions.

A real intelligence quotient test is a structured, researched and clinical assessment with psychological backing and conducted by a trained professional.

Unlike the gimmicky ‘cognitive tests’ online, if you actually want your own or your child’s IQ you need an actual, valid reason to undertake the test. A psychologist is unlikely to administer a test just to indulge in your curiosity.

What are IQ tests used?

IQ tests can be administered and used for a number of reasons. The most common reason why a parent would be seeking to find out their child’s IQ is to ‘diagnose’ poor school performance. For adults, the most common reason for wanting an intellgience quotienttest is for career guidance or to determine job suitability.

What is in an IQ test?

IQ tests begin to assess a person’s intelligence quotient by measuring their short-term and long-term memory. It also measures how well individuals can solve puzzles or recall information they have heard, as well as how quickly they can complete these activities. There are two main components to the test: verbal and non-verbal.

Is IQ important?

This is a difficult question to answer because it depends on what you want it for. Low IQ doesn’t mean an individual is unable to have a high quality, successful life, and vice versa. Most people have the capacity to learn regardless of their intelligence quotient score. However, some are simply able to learn more quickly or more easily than others.

Some people may struggle in one area and have a weakness in one or more types of intelligence which would have having a special education programme at school invaluable for children. By knowing an IQ score, the teacher will know how much assistance the child needs and in what specific area or areas. Conversely, some people have a natural gift in certain areas of intelligence. They too would benefit greatly from a specialised education programme that is designed to help extend and develop their minds.

There are many reasons why an IQ score can be of use including but not limited to:

  • Assisting with the diagnosis of a child or adult.
  • Helping with educational placement and the implementation of a suitable education programme for children.
  • Helping employers decide if a particular person is suited for a particular job.

Are IQ tests accurate?

One of the most important things to remember is that an IQ only measures a person’s potential as determined by that particular test on that particular day at that particular point in time. The test participant may have been feeling unwell that day. They may have had a poor night’s sleep the previous night, or had an argument on the way to the test. Even not eating breakfast the morning of the test can affect results. (For more on the connection between what you eat and how your brain functions, read our blog How Food Affects Your Mood.)

Of course, these are just some examples of things that may impact the results achieved on that particular day. The reality is that IQ results are usually fairly accurate. The psychologist conducting the test ensures this by making sure they don’t just look at the test score in isolation. If they’re working with a child, for example, they might take into account other factors. These can include the child’s prior school performance, family circumstances, or any other contributing and contextual factors.

IQ test results obtained that are very different to what was expected—given all of the background information about the child—would then prompt the psychologist to look more deeply at the possible causes.

Remember, psychologists are trained for this sort of thing. They know what they’re doing and, while not infallible, are quite good at getting accurate and informative IQ results.

Does IQ determine success?

As we mentioned above, one’s intelligence quotient does not necessarily determine success. After all, IQ tests are designed to measure a person’s potential. It does not take into account other very important factors like ambition, motivation, opportunity, the ability to think clearly under pressure etc. etc.

Some people have a high IQ but also have high levels of anxiety which results in poor performance on tests and exams. Other people have a high score but struggle to properly express themselves in the written form, which is the form most exams are in. Just because someone has a high quotient score does not mean they will do well at school.

Conversely, if someone does not have a high IQ and does not perform well at school they may very well go on to succeed in their chosen career, which may or may not be more practical in nature.

It is also important to bear in mind that an IQ test only shows what is contained in that particular test. Most IQ tests are designed to measure a set of skills that are important to the society in which the person being assessed lives in. But what about someone who is a gifted musician? Or a talented carpenter?

The skills involved in these pursuits are different, certainly, but they are also a type of intelligence. This sort of test just doesn’t measure it.

A final word on understanding IQ

Intelligence quotients are definitely useful and can be instrumental in clinical practice and education, but it is important to remember what such tests are and aren’t good for. An IQ score tells a story but not always the whole story. It can be critical for helping someone on the road to success but not crippling. And it can be informative to know and sometimes unnecessary.

At One Central Health, our team of trained psychologists can provide comprehensive and accurate IQ tests for clients of all ages.

If you would like to know more about what IQ is or more information about tests, get in touch with our team today by calling (08) 9344 1318.

– Nina Shapiro

Is a measure of intelligence that takes into account a person's chronological and mental ages?

IQ, (from “intelligence quotient”), a number used to express the relative intelligence of a person. It is one of many intelligence tests. IQ was originally computed by taking the ratio of mental age to chronological (physical) age and multiplying by 100.

What is the term for a measure of intelligence that takes into account?

intelligence quotient (IQ) A measure intelligence that takes into account an individual's mental and chronological ages.

Is IQ used to measure intelligence?

An intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence.

What does IQ measure quizlet?

An intelligence quotient or an IQ is a numerical score on an intelligence test. It shows how much someone's intelligence score, measured by the test compares with other people of the same age.