Most IQ tests are standardized so that they can be scored and interpreted with the same system, providing a fairly simple way of understanding and interpreting each individual IQ score. Key things to remember when interpreting an IQ score include the percentile, the percent of the population that scores at or near a specific score, and the “title” or category associated with each range of scores. Also, it is important to remember that IQ tests only measure one aspect of a person on the particular day the test is taken, and should not be taken as an overall representation of that person’s capabilities and likelihood of success throughout life.
In order to fully understand an IQ score, you must be familiar with percentiles. A percentile does not describe the percentage of answers correct on a test, as most people are familiar with on academic tests. A percentile instead gives a picture of how well a particular test taker did in comparison with everyone else taking the test. A score in a certain percentile means that that person performed better than that specific percent of the people taking the test. For example, a person scoring in the 85th percentile would have scored higher than 85% of the rest of the test takers.
The first thing you need to understand about most IQ tests is that a score of 100 is average. A score of 100 or near to it can be commonly misunderstood as a “perfect” score of 100%. However, if a score of 100 is average, that means that someone who scored 100 on an IQ test scored in the 50th percentile. A score of 135 or higher would be in the 99th percentile, indicating that a person achieving this score would have scored higher than 99% of the other people taking the test. Also, half of everyone who takes an IQ test should have scores that fall between 90 and 110.
There are some controversial “categories” that scores fall into that describe the intelligence level of people scoring within that range. For instance, because half of all test takers have an IQ score between 90 and 110, that range is labeled “average” with some methods of interpretation. The category titles change somewhat, with some methods including “genius” and “mentally challenged” and others just sticking with “above average” and “below average.” They almost all agree, however, that these designations should not be taken with absolute authority, because it would be silly to consider a person with a score of 140 a genius when someone scoring a 139 would not be, for example.