Meaning of an IQ score
What does an IQ score mean? After taking an IQ test, you might need some help with the interpretation of your IQ score to understand what your IQ score actually tells you. Do you have an average IQ, a genius IQ? The table below shows the IQ score range as derived from Resing and Blok (2002)1 and provides a clear overview. The table distinguishes different categories based on the height of your IQ score, meaning you gain some understanding of your capacities.
|IQ||Percentage of the population with this IQ||Interpretation|
|> 130||2.1||Very gifted|
|111-120||15.7||Above average intelligence|
|80-89||15.7||Below average intelligence|
About 2% of the population has an IQ score lower than 69. Such a low IQ score often is hard to measure using a regular intelligence test. Very high IQ scores are also hard to determine accurately. This is because you need a lot of reference measurements to determine a specific score reliably. As very high and very low IQ scores simply do not occur often, it is hard to form such a reference group.
The normal distribution
Although the IQ score is widely known as a psychological statistic, its relation to other statistical measures is lesser known. The best way to explain these measures and their relations is using the normal distribution, also know as the Bell Curve.
The IQ score chart below shows a visual representation of a normal distribution. Think of the horizontal axis as all the different scores one could possibly get, lowest through highest. The vertical axis represents the number of people that obtain that specific score.
1Resing, W.C.M., & Blok, J.B. (2002). The classification of intelligence scores. Proposal for an unambiguous system. The psychologist, 37, 244-249.