How to Read IQ Test Scores

You have taken an IQ test and you were given a number, but how do you really read IQ test scores? IQ tests give a score that is supposed to tell how intelligent a person is. But can we really reduce all of our intelligence down to a single number? When we get that number, how do we know what it really means? Follow these steps as a guide to understanding what those test result numbers really mean.

In order to read IQ test scores, find out the name of the test you took, what type of IQ test it is and where it came from.

All IQ tests are not alike and so you have to know something about the test to know what the score means. These are some of the things to look for.

 Is it a comprehensive test? A comprehensive IQ test will measure both verbal and non-verbal skills.  It will also measure all areas of intelligence, including working memory, long-term memory, visual and auditory processing, crystallized intelligence (mostly learned knowledge and your ability to apply that knowledge), fluid intelligence (more innate reasoning and problem solving abilities) and processing speed.

 A good IQ test is also standardized.  That means that the scores were determined by how a sample of people (generally the sample matches US census data to include all races, socio-economic groups, M/F, age groups, etc.) did on the test.  Not all tests are comprehensive and standardized.  On-line IQ tests are not. They may be fun to take, but their results can be questionable.  Not all standardized tests are comprehensive. Some test only non-verbal intelligence and some test only verbal intelligence.

 Some of the better tests (they are standardized, comprehensive and have a good reputation) include the Wechsler, Woodcock-Johnson, Reynolds, Differential Abilities Scales, Stanford-Binet, and the Kaufman.  That is not a complete list but gives a short-list.

 Also, these tests are updated regularly. This makes sure that the scoring is still valid, that they are as culture free as possible, etc.  Do not take an outdated test. If you are being given a test, ask if it is the latest version.  Plug the test name into an internet search and see if there is a later version.

In other words, you can only read IQ test scores in light of the test you took.

Find out what the overall IQ score is.

If you took a comprehensive IQ test that was standardized, then the first number to read is the overall IQ score. That score may be called a full scale score, the general conceptual ability, etc, depending on what test you took.

Standardized IQ tests will have an average and a standard deviation. The average is 100 and the standard deviation is usually 15. Without getting too statistical, that basically means that about 68 percent of the population would score within 15 points of the average (100). So about 68% would score anywhere form 85 to 115. That is the average range. A score above 115 or below 85 would be more rare. A score below 70 would only occur in about 2% of the population. A score below 70 is associated with mental retardation if there are also deficits in adaptive behavior skills.

Assess the factors that impact the overall IQ score.

Because IQ tests are standardized, they have to be given in exactly the same way every time. They have to be given by a professional who is trained and knows how to give the test correctly. There should be little difference between test scores when given on different days, by different examiners, etc. However, if you think your IQ test score is not accurate (usually meaning too low) then ask what the examiner's experience is. Ask to have it re-scored just to double check. Also, ask yourself if you gave your best effort. Given your very best effort, no outside interference (such as noise, a headache, etc.) and a knowledgeable and accurate examiner, your score should be valid.

The test will give you a confidence interval that your score would fall in. Usually, this means that within a certain level of confidence (usually 90 or 95%) your score would fall into a range on any given day. This range is usually plus or minus 4-6 points either way. So, if your score is 100, that means that on any given day you would have scored between (let's assume the interval is 5 points either way) 95 and 105.

Now that you know you took a good test and you know what your overall score is and you are confident that it is valid, look at the scores that made up the overall score.

There are several areas of intelligence (see step 1) and hopefully your test measured all of them. Two people can have the same overall score yet have completely different strengths and weaknesses within the different areas of intelligence.

Ask to look at each of the subtest scores and at the breakdown of scores in different areas. That will tell you if different areas (such as your processing speed, reasoning abilities, visual processing, etc.) are strengths or weaknesses. This is good information to use to know what you might work on to improve or to know how you tend to take in information.

Determine the importance of the IQ scores to you.

Know that an IQ score only represents limited information about ones ability to succeed in life. There are many things that factor into success beyond what an IQ test is able to measure. Things such as motivation, effort, and social skills will have a huge impact. IQ tests are only the best way we currently have to quantify intelligence.