Hereditarians were right again. For decades egalitarians have disrupted Lynn's ~70 IQ estimate for sub-Saharan Africa. The data were sparse, conditions questionable, samples insufficiently representative, tests possibly biased. All true, but the pattern was clear enough given the limitations. Now in 2025 PISA finally included more African countries. Using their values and British natives (born in UK + both parents born in UK), these are the IQs: Kenya 73 Zambia 71 Rwanda 71 Morocco 78 The issue you see on the left is that their performance is at the level of guessing for many students, so the normal distribution becomes compressed and the mean inflated. This is a classic floor effect. I rescored the data for the countries with item-level data using the 3PL model, and this reduces the mean estimates by 2 for Morocco and 5 for Kenya (78→76, 73→68).