Average IQ by country
Lists of average IQ by country circulate widely online. Before you trust one, it helps to know where the numbers come from.
Where the rankings come from
Most national IQ lists trace back to compilations started in the early 2000s, which gathered old studies run with different tests, in different years, often on small groups such as one school or one village. For many countries, no representative sample was ever tested.
Why researchers criticise them
A few hundred people tested decades ago cannot stand for a whole country today. Tests built in one culture and language also work less well in another, and scores were often adjusted with assumptions to fill the gaps.
Because of this, many researchers consider such rankings unfit for comparing countries, and some datasets have been formally challenged in the scientific literature.
What moves national averages
Where better data exists, average scores track schooling, health and living standards. Years of education, nutrition, lower exposure to disease and pollution, and familiarity with test-taking all raise scores. That is why averages rose sharply in many countries during the twentieth century, by around three points per decade.
Better ways to compare countries
If you want to compare skills between countries, international studies of students and adults, such as the large school assessments that test reading, maths and science with the same questions in every country, use representative samples and published methods. They measure learned skills rather than IQ, but they are far more reliable.
What this means for you
A country’s average says nothing about any one person. Differences within every country are much larger than the differences reported between them.
Questions
Which country has the highest IQ?
Published lists usually put East Asian countries at the top, but the underlying data is uneven enough that the exact order is not meaningful.
Has average IQ gone up?
Yes, in most countries during the twentieth century. In a few wealthy countries the rise has stalled or reversed slightly since the 1990s, for reasons still debated.