I just answered this question on Quora not too long ago so I thought I would repost it here.
The median IQ with current modern tests is 100 with a standard deviation of about 15 points.
This means that 50% of people will score above 100 and 50% will score at or below 100.
According to the distribution of IQ among people, 10% of people will score an IQ measure above 120. This means that if you measure intelligence by your IQ score, then if you score more than 120, you are in the top 10% smartest people!
Here are few of the tests that have been derived and are currently in use for measuring IQ:
- Wechsler test (there is one for adults and one for children)
- Woodcock-Johnson test of cognitive abilities
- Kaufman Assessment Battery
Now what do different IQ scores mean? According to the Wechsler classification (one of the most popular, you can see it at):
A score between 90 and 109 means average intelligence, that encompasses 50% of the population. A score between 110 and 119 is higher than average, that’s 14% of the population. A score above 120 is 10% of the population, like I mentioned before.
Now how does IQ and intelligence relate?
- Something has been identified and called the Flynn effect. It’s the name for the fact that IQ scores have been increasing on average over time (let’s say over the last century).
- Being intelligent is not the same as being “book smart” or “street smart” or just “wise”. It relates more to your ability to understand concepts, think in abstract terms, imagine, being creative, how much of a quick learner you are.
- Real intelligence happens when you can combine both rational intelligence with the social or emotional intelligence that all (or most) humans are capable of.
So what’s our conclusion here? IQ tests are a somewhat vague measure of intelligence. A score of 120 tends to indicate superior capabilities in thinking abstract, dealing with hypothesis, and maybe a quicker brain? However, you need to understand that IQ is only an indirect measure of intelligence, even though it probably correlates with it.