(Observation 3) Qualitative trends of portability can depend on the measure of prediction accuracy used. For some traits our measure of group-level prediction accuracy often drops where at the individual level, it increases.

(19/27)

Relatedly, some cool recent work from @roshnipatel.bsky.social, Jeffrey Spence, @jkpritch.bsky.social et al. dives deep into expectations, based on models of natural selection, for allele frequency in a group B conditional on allele frequency in group A.

academic.oup.com/genetics/art...

(16/27)

(Observation 1) Previous work suggested genetic distance from the GWAS sample largely explains variation in PGS performance. However, what we see empirically is that prediction accuracy is extremely noisy at the individual level.

(5/27)

Sounds like an Erdős problem

But once again, the same trait can show very different sign bias across biobanks. Example: we estimate 72% of rare minor alleles (sign bias of 0.44) increase risk of type 2 diabetes in All of Us, while ~all increase risk in UK Biobank. Why? (11/21)