CognitiveDrill

Statistics

What the numbers actually are. Averages, spreads and age curves for the abilities these tests measure.

How to use these figures

Every page here names where its numbers came from. Where a figure is drawn from published research rather than from our own visitors, the page says so in the same breath as the number.

You are welcome to cite any of it. All we ask is a link back to the page you took the figure from. That lets your reader check the source for themselves.

None of these numbers is a threshold. A distribution tells you where a score sits among other people. It does not tell you whether that score is a problem, and no page here will pretend otherwise.