Average IQ by Country

Where the data comes from: national IQ figures are not measured country by country under a common standard. They are compiled from scattered studies, then adjusted and estimated to fill gaps — in some cases extrapolated from neighboring countries rather than measured at all.

The sampling problem: this is the central criticism. Many underlying samples were small, drawn from a single city or school, or unrepresentative of the wider population. Comparing a figure built from a few hundred urban students against one built from a national sample is not a like-for-like comparison.

Tests travel badly: performance depends on schooling, literacy, familiarity with timed multiple-choice formats, and translation quality. A lower national figure can reflect differences in access to education rather than anything about reasoning ability.

The Flynn effect: measured scores rose substantially across many countries through the 20th century, far too quickly for genetics to explain. This is strong evidence that environment and schooling move these numbers — and it means any ranking is a snapshot tied to when the data was gathered.

What this says about you: essentially nothing. Variation between individuals within any country dwarfs the differences between national averages.