What the commenter Cicerone wrote in response to the study about dysgenic decline in Germany.
The findings come rather surprizing to me and I am always sceptical of using these low N studies to make out trends.
Using fertility by education data from the Wittgenstein database, my estimate for the intrinsic IQ loss over the next generation is 1.0. That of course doesn’t take migration into account and only incorporates differences in fertility rates by education classes. Contrary to the past, these fertility rates don’t differ that much anymore. University educated women in Germany have a TFR of 1.3, vs. 1.45 for medium educated women and 1.6 for the least educated.
Fertility driven IQ losses per generation for other countries:
Belgium and Finland: 0 (the best scoring countries in the world, no dysgenic fertility here, rest of Scandinavia not far behind)
Indonesia: -0.6 (best scoring developing country)
France: -1.3 (France has a very fertile underclass compared to the UK or Germany)
South Korea: -1.4
Singapore: -1.4 (the only country openly following eugenic fertility policies, with dismal results it seems)
Romania: -2.9 (worst scoring European country, everyone knows why)
Brazil: -3.9 (worst scoring major country, educated women in Brazil have extremely few children (1.2 on average))
Afghanistan: -5.1 (worst scoring country on earth)