An IQ score is not simply a count of how many questions you answered correctly. It is a statistically standardized number that shows how your performance compares to other people who have taken the same test. This page explains how that number is actually calculated, using the WIQS Official Test as an example.
From raw score to IQ score
Your WIQS score is calculated based on the number of correct answers out of the 35 Official Test questions, compared against the score distribution of other test takers. As with most IQ tests, this is based on a normal distribution model (a “bell curve”) with a mean of 100 and a standard deviation of 15. As more people take the test, the accuracy of this distribution model continues to improve.
In practice, this means two things:
- Your raw number of correct answers is converted into a position within the overall distribution of scores, not used directly as your IQ.
- A score of 100 represents the statistical average, while scores above or below 100 show how far you are from that average, in steps of about 15 points (one standard deviation).
Why a bell curve?
Cognitive abilities across a large population tend to follow a normal distribution: most people cluster around the average, with progressively fewer people at the very low or very high ends. Using this model lets a single number (your IQ) express both your raw performance and how unusual that performance is compared to everyone else who has taken the test. For a broader look at what these numbers mean in practice, see What Is a Good IQ?
What affects the calculation
- Number of correct answers — the 35 Official Test questions increase in difficulty, so later correct answers carry more weight.
- Sample size — the distribution model is continuously refined as more people take the Official Test, which improves accuracy over time.
- Test conditions — factors like a quiet environment and full concentration during the 25-minute time limit help ensure your score reflects your actual performance.
For more on what IQ itself represents, see What is IQ?. To understand the broader concept of intelligence that IQ attempts to measure, see What Is Intelligence?
See how your own score is calculated.
Take the free WIQS Pretest.