Glossary
Standardization sample
Definition
A standardization sample, also called a norming sample, is the large group of people a test is given to before release. Their results define what average and above average mean on that test, separately for each age group. Every IQ score is a comparison with this group.
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Why it matters for IQ scores
An IQ of 100 means “average for your age in the reference group”. The publisher standardizes results so that each age group in the sample has a mean of 100 and a standard deviation of 15 (Wikipedia: Intelligence quotient). If the sample is old, small or unrepresentative, every score built on it inherits the problem.
Why norms go out of date
Average measured IQ rose through the 20th century. A meta-analysis of 271 samples estimated gains of about 2.8 points per decade, slowing in recent decades (Pietschnig & Voracek, 2015). A decline has been reported in Norwegian conscript data for cohorts born after about 1975 (Bratsberg & Rogeberg, 2018). Either way, a test scored against old norms can drift away from the meaning of 100 today. That is why new editions such as WAIS-IV and WAIS-5 are normed against new samples.
Common confusions
The sample defines the scale; it does not set a pass mark. Two well-built tests normed on different samples can give the same person slightly different scores. Related terms: age norms, mean and the negative Flynn effect. For the long story, read the Flynn effect and why IQ tests are renormed.
Try one · Quantitative Reasoning
Which number comes next?
2, 5, 10, 17, 26, ?
Tap the option you think is right, or show the answer.
Show the answer
The next number is 37 (option 2).
How to solve it
- The gaps (3, 5, 7, 9) grow by 2 each time, which is the pattern of square numbers.
- Each number is a square number plus 1: 1 × 1 + 1, 2 × 2 + 1, 3 × 3 + 1, 4 × 4 + 1, 5 × 5 + 1.
- So the next number is 6 × 6 + 1 = 37.
That was 1 puzzle. The full test has 25.
Sources
- Intelligence quotient. Wikipedia. en.wikipedia.org/wiki/Intelligence_quotient
- Pietschnig, J., & Voracek, M. (2015). One century of global IQ gains. Perspectives on Psychological Science, 10(3), 282-306. doi.org/10.1177/1745691615577701
- Bratsberg, B., & Rogeberg, O. (2018). Proceedings of the National Academy of Sciences, 115(26), 6674-6678. doi.org/10.1073/pnas.1718793115