In 2002 Richard Lynn and Tatu Vanhanen’s book IQ and Wealth of Nations estimated the IQs of 185 countries. Critics accused them of cherry picking sources, using unrepresentative samples, comparing and combining samples tested on wildly different tests taken decades apart, and daring to think IQ could be measured cross-culturally. And yet despite nearly two decades of opprobrium, those national IQs remain a landmark, cited in countless peer reviewed articles and repeatedly revised.

One way Lynn has validated his numbers is by showing their high correlation with international exams like Programme for International Student Assessment (PISA). Another independent data-set against which Lynn’s numbers can be tested (assuming he already hasn’t done so) is the IEA‘s Trends in International Mathematics and Science Study (TIMSS). Ostensibly an achievement test, the math section resembles an IQ test, and the test is scored so that most countries average between 400 and 600.

Sample items:

Using the score distribution of UK students as a reference group (see technical note below), I converted the scores from 39 countries to IQ equivalents. My source for the TIMMS scores is exhibit 1.2 in this report.

Country TIMMS score (8th grade math; 2015) IQ equivalent Singapore 621 118 Korea, Rep. of, 606 116 Chinese Taipei 599 114 Hong Kong SAR 594 113 Japan 586 112 Russian Federation 538 103 Kazakhstan 528 102 Canada 527 101 Ireland 523 101 United States 518 100 England 518 100 Slovenia 516 99 Hungary 514 99 Norway 512 99 Lithuania 511 98 Israel 511 98 Australia 505 97 Sweden 501 97 Italy 494 95 Malta 494 95 New Zealand 493 95 Malaysia 465 90 United Arab Emirates 465 90 Turkey 458 89 Bahrain 454 88 Georgia 453 88 Lebanon 442 86 Qatar 437 85 Iran, Islamic Rep. of 436 85 Thailand 431 84 Chile 427 83 Oman 403 79 Kuwait 392 77 Egypt 392 77 Botswana 391 77 Jordan 386 76 Morocco 384 76 South Africa 372 73 Saudi Arabia 368 73

Consistent with Lynn’s hierarchy, we find that East Asian countries cluster around the top (Japan IQ 112 to Korea, Repub of, IQ 116), followed by white majority countries (New Zealand IQ 95 to Russian federation IQ 103), followed by Dark Caucasoid countries (Saudi Arabia IQ 73 to United Arab Emirates IQ 90) and lastly sub-Saharan countries (South Africa IQ 73 to Botswana IQ 77). And while Lynn’s data was ridiculed for declaring entire countries “mentally retarded”, it’s perhaps a sign of higher quality data that no country in this data-set averaged below IQ 70 (though most of the poorest countries chose not to participate).

Technical note

On page 95 of the report, we’re told that only 10% of England’s 8th graders could score 625+, 36% could score 550+, 69% could score 475+, and 93% could score 400+. Subtracting these percentages from 100 gives the following percentiles: 90, 64, 31, and 7 which can be converted to the following IQs: 119, 105, 93, and 78. Now that we have the IQ equivalents of four TIMMS scores, we can make a linear equation converting TIMMS to IQ which is IQ = 0.18(TIMMS score) + 6.5: