Summary
- I estimate there is a correlation of 85.4 % across countries in 2019 between the real GDP and population with IQ higher than the global mean. This is stronger than the correlation of 78.4 % between the real GDP and total population.
- Among the 20 countries with the largest real GDP, the population with IQ higher than the global mean will increase the most for India (53.5 M), the United States (39.4 M), and Indonesia (15.7 M).
Acknowledgements
Thanks to alsilverback from Batonics AB.
Methods
I determined the population with an IQ above a given z-score of the global distribution assuming (see tab “Population by IQ” of this Sheet):
- 2019 population data by country from Our World in Data (see tab “Population”).
- The mean IQ globally and of each country from Table 16 of Lynn 2019, and coefficient of variation of 15 %[1] (see tabs “Global IQ” and “IQ by country”).
To my knowledge, Lynn 2019 is the best source of IQ data by country, but it arguably does not differ much from other good sources. The correlation coefficient for the relationship between the mean IQ by country from Lynn 2019 and WordData is 88.7 %[2] (see M2 of tab “IQ by country”).
I selected data from The World Bank for the total and per capita real GDP in 2019 by country (see tab “Real GDP”).
Results and discussion
The table below contains the correlation coefficients for the relationships across countries in 2019 between the real GDP and the real GDP per capita, population, mean IQ, total IQ[3], population with an IQ higher than various z-scores of the global distribution, and total IQ of top half.
Relationship between the real GDP in 2019 and… | Correlation coefficient (R) (%) | |
---|---|---|
Real GDP per capita in 2019 | 13.1 | |
Population in 2019 | 78.4 | |
Mean IQ | 24.3 | |
Total IQ in 2019 | 82.7 | |
Population in 2019 with an IQ higher than… | 3 standard deviations below the global mean | 78.5 |
2 standard deviations below the global mean | 80.0 | |
1 standard deviation below the global mean | 84.9 | |
The global mean | 85.4 | |
1 standard deviation above the global mean | 80.0 | |
2 standard deviations above the global mean | 76.1 | |
3 standard deviations above the global mean | 73.3 | |
Total IQ of top half | 84.0 |
The population with IQ higher than the global mean is the strongest predictor of the real GDP (R = 85.4 %), better than the population alone (R = 78.4 %). Consequently, I think it may be interesting to analyse how the former will evolve. The following table presents, for the 20 countries with the largest real GDP[4], the absolute and relative variation from 2019 to 2050 of the population with IQ higher than the global mean, assuming the same parameters from Lynn 2019 for the IQ distributions.
Country[5] | Variation from 2019 to 2050 in the population with IQ higher than the global mean | |
---|---|---|
Absolute (M) | Relative (%) | |
China | -27.5 | -1.92 |
United States | 39.4 | 12.0 |
India | 53.5 | 3.92 |
Japan | -18.9 | -14.9 |
Germany | -2.85 | -3.41 |
Russia | -7.65 | -5.25 |
Indonesia | 15.7 | 5.82 |
United Kingdom | 5.31 | 7.87 |
Brazil | 7.47 | 3.54 |
France | 1.89 | 2.90 |
Mexico | 15.2 | 11.9 |
Turkey | 7.18 | 8.61 |
South Korea | -3.76 | -7.35 |
Spain | -2.21 | -4.72 |
Canada | 6.75 | 18.0 |
Saudi Arabia | 2.05 | 5.99 |
Thailand | -2.15 | -3.09 |
Poland | -3.50 | -9.25 |
Australia | 6.19 | 24.5 |
Iran | 6.22 | 7.50 |
Amongst these 20 counties, the 3 whose population with IQ higher than the global mean is predicted to have the largest:
- Absolute variation are India (53.5 M), the United States (39.4 M), and Indonesia (15.7 M).
- Relative variation are Australia (24.5 %), Canada (18.0 %), and the United States (12.0 %).
- ^
I set the coefficient of variation to 15 % because, according to Wikipedia:
For modern IQ tests, the raw score is transformed to a normal distribution with mean 100 and standard deviation 15.
- ^
However, note the values from WordData rely on many studies from Lynn:
The intelligence quotients by countries are taken from the studies conducted by Richard Lynn and Tatu Vanhanen (2002), Heiner Rindermann (2007), Khaleefa and Lynn (2008), Ahmad, Khanum and Riaz (2008), Lynn, Abdalla and Al-Shahomee (2008), Lynn and Meisenberg (2010), as well as the PISA tests in 2003, 2006 and 2009. More recent results were weighted higher. The studies are not entirely uncontroversial as they often consider only specific population groups or a few individuals per country. If, on the other hand, an average is obtained from all the tests and studies, a usable overview will be obtained.
- ^
The total IQ is the product between the mean IQ and population.
- ^
See tab “Population by IQ” for the full results.
- ^
Ordered from largest to smallest real GDP in 2019.
I take your word for it that you're naïve about Lynn's work on race and IQ. I don't fully buy into the idea that defensive writing is bad per se, but I won't litigate that here. I don't think the central errors I was criticising are relevant to this. Briefly:
To be totally clear, I believe you that you don't find this interesting for issues relating to race, I just don't think given that debate informs an understanding of both the data and its context, that it should be ignored. Unfortunately, information doesn't exist in a vacuum.