Average IQ by Country: What the Rankings Really Show

Your country's average IQ (and more rankings you didn't know)

If you came here looking for one tidy number for your country, here is the honest answer first: the "average IQ by country" tables that circulate online are not reliable measurements. Most of them descend from a single dataset assembled in 2002 from small, mixed and often outdated studies, and for more than half of the countries listed nobody had actually tested a national sample at all. They can still be a fun talking point, much like average shoe size or height, but they say far less about a nation than their neat decimal points suggest.

The chart below came from OnAverage.co.uk, a British site that collected light-hearted averages about bodies, habits and lifestyles so readers could see where they landed. It is worth enjoying in that spirit, and then reading with a careful eye.

Where do the country IQ numbers come from?

Nearly every viral ranking traces back to the work of psychologist Richard Lynn and political scientist Tatu Vanhanen, whose book IQ and the Wealth of Nations appeared in 2002, followed by IQ and Global Inequality in 2006. They did not run new tests. Instead they gathered existing studies, adjusted older scores upward to allow for rising results over time, and filled the gaps by borrowing figures from neighbouring or "comparable" countries.

That last step matters a great deal. According to the summary of the book's method, real test data existed for 81 of the 185 countries in the table; the other 104 were estimates. El Salvador, for example, was given the average of Guatemala and Colombia. Even where data existed, it was often thin: dozens of national figures rested on a single study, and some on groups of only a few dozen children.

ONAVERAGE.CO.UK

So when a chart puts one country at the top and another near the bottom, it is often comparing a well-studied population of urban schoolchildren in one place with a guess, or a tiny rural sample, somewhere else.

What researchers have found wrong with the rankings

Criticism started early and has grown sharper. Psychologist Richard Nisbett described the samples as small and haphazard. Jelte Wicherts and colleagues reviewed the African data in 2010 and concluded that the selection of studies was unsystematic and impossible to replicate; using a broader set of studies, they put the sub-Saharan average around 80 rather than the much lower figures in the original tables. Other reviewers objected that the book leaned on simple correlations and treated them as if they proved cause and effect.

The debate has not stayed academic. In 2020 the European Human Behaviour and Evolution Association advised researchers not to use the dataset or its updated versions. Since then, psychologist Rebecca Sear of Brunel University of London has written to journals that published work based on it. Retraction Watch reported in November 2025 that two papers had been retracted, Elsevier had opened a review of past articles using the data, and her running list counted 174 studies relying on it.

None of this means intelligence tests are meaningless. Within a well-designed study, IQ scores predict some things, such as school performance, reasonably well. The problem is specific: stitching together incompatible studies from different decades, ages and test types, then presenting the result as a league table of nations.

Why scores rise and fall with circumstances

One of the strongest clues that national averages reflect living conditions as much as anything innate is the Flynn effect, named after the New Zealand researcher James Flynn. Through the 20th century, raw scores on IQ tests climbed in many countries, by roughly three points per decade in the United States. Genes do not change that fast. Longer schooling, better nutrition and health, less disease and lead exposure, and more familiarity with abstract, test-like problems are the leading explanations.

Some wealthy countries, including Norway and Denmark, have since seen scores level off or dip slightly, which researchers are still trying to explain. Either way, the lesson is the same: a population's average responds to schools, food, health care and the kind of thinking daily life demands. A figure measured in one decade can be badly out of date in the next.

This is why a sentence often attached to these charts deserves to be stated plainly: test scores mix reasoning ability with education, language, test familiarity and health. They are not a pure readout of how clever a people is.

Why we love comparing ourselves

If the numbers are so shaky, why do these lists spread so easily? Psychology has a good answer. In 1954 Leon Festinger proposed social comparison theory, the idea that when we lack an objective yardstick, we judge our abilities and opinions by looking at other people. A country ranking hands us a ready-made yardstick, and we instantly check where "we" stand.

Researchers distinguish two directions. Looking down at those who seem worse off can make us feel better about ourselves. Looking up at those who seem better off can sting, although it can also motivate, especially for people who already feel secure. Context decides which way it goes.

Social media turns this up to full volume. Feeds are curated highlight reels, and studies have linked heavy upward comparison on image-focused platforms with lower self-ratings, stress and fear of missing out. A survey in Singapore found that Instagram use affected social anxiety mainly through comparison and self-esteem rather than directly. That nagging feeling while scrolling usually means you are measuring your ordinary day against someone else's best moments, and the people you envy are very likely doing the same thing.

Smiles and grimaces: enjoying rankings without being fooled

Lists like OnAverage's were built to be browsed for fun: average shoe size, height, hours of sleep and much more. Some results make you grin, others make you wince. Here is how the original page imagined the two reactions:

via GIPHY

The happy reaction, and the other one...

via GIPHY

A few habits help you enjoy these comparisons without taking away the wrong message:

Ask where the number came from. A measured average from a large, representative survey is very different from an estimate borrowed from a neighbouring country.
Check the date. Scores, heights and even shoe sizes shift over generations as nutrition and schooling change.
Look at the spread, not just the average. The variation inside any country is far larger than the gaps between national averages.
Watch for leaps from correlation to cause. Richer countries tend to score higher on tests, but better schools and health could easily drive both.

Common myths about national IQ

"The rankings prove some nations are born smarter." They do not. The data quality is too poor to support that, and the Flynn effect shows how strongly averages track environment.

"Every country was tested." Most were not. In the original tables, more countries were estimated than measured.

"An IQ score is a complete measure of intelligence." IQ tests capture certain reasoning and knowledge skills under test conditions. Creativity, practical judgement and emotional skills are only partly reflected, if at all.

If you want to know how you compare, the most useful comparison is usually with yourself a year ago. That yardstick is fair, up to date and entirely under your control.

Sources: Wikipedia: IQ and the Wealth of Nations; Retraction Watch, 25 November 2025: researcher aiming to halt use of the national IQ database; Wikipedia: Flynn effect; Wikipedia: Social comparison theory; chart from OnAverage.co.uk, first shared via Science Dump; GIFs via GIPHY.

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