The issue with early interventions for cognitive traits
There are numerous intervention studies aim at improving cognitive traits. While one can aggregate these in ways that give the appearance of impact, when looked at properly they don't really…
Two new review articles on national IQs
Heiner Rindermann sent me his new review paper: Rindermann, H. (2025). Low cognitive ability estimates in developing countries: A statistical analysis of their credibility. Human Evolution, 40(3–4), 257–284. https://doi.org/10.14673/HE2025341159, Developing countries…
What explains the Big Pisa Decline of 2022? It’s not COVID
You may have seen posts like this: Two explanations are commonly offered: Phones/computers got suddenly more addictive than before (Tiktok-era) COVID was bad for learning. Let's start with the second.…
New causal variant estimates for intelligence
There's a new genetic analysis of intelligence out: Chen, H., Liao, Y., Tang, L., Wei, X., Li, T., & Chen, W. (2025). Multivariate genome-wide analysis reveals shared genetic architecture and…
Population size is not important for country outcomes
There is a recurrent feature of the immigration debate that goes like this: Emil: Look at how negative the fiscal contributions of 3rd world migrants are. People: Heh, that's nice,…
Migrant selection and informative priors
Chris Rufo wasn't happy with the recent American experience with the Somalians scamming the welfare state and wrote about how one should take into account "which national populations" people wish…
Against the economists on school spending
Some days ago I posted a chart about school spending (per-pupil spending) and math test scores: Note how I didn't say this cross-sectional scatterplot proves anything about causality, but we…
Are IQ scales interval or ordinal?
One of the more obscure objections to intelligence testing is that really the tests are only on ordinal scale, and thus many of the usual statistical operations are undefined. Recall,…
What did the new WGS UKBB study show?
I wasn't going to blog this, since I prefer not covering the same ground as others, but due to multiple requests and questions, I will cover it anyway. It's this…
Science vs. ideology on vertical transfers
Last year Marcus Feldman and Kevin Lala published one of those anti-hereditarian pieces: Lala, K. N., & Feldman, M. W. (2024). Genes, culture, and scientific racism. Proceedings of the National…