Education has improved the average IQ of multiple East Asian countries by 15 points over two decades. That's an entire standard deviation improvement for the w

Education has improved the average IQ of multiple East Asian countries by 15 points over two decades. That's an entire standard deviation improvement for the whole population. One-on-one tutoring has been shown to make a two standard deviation difference. That's the difference between median intelligence and genius. https://en.wikipedia.org/wiki/Bloom%27s_2_sigma_problem https://en.wikipedia.org/wiki/Bloom%27s_2_sigma_problem Your study is about the effect of an extra year of badly done education on people who drop out of school, which is worth 1 IQ point. That same study shows that the effect of mediocre education on people who don't drop out of school is an increase of 5 IQ points.