Tantaman's work is a very interesting block of research on why one group buys into the demographic transition more than some others. I think it's an interesting angle.

On interpreting data, seems like they're coming at LessWrong from a different angle? Bayes? Scientific Method? [1]

A bit more detail:

Demographic transition has been an explicit policy goal for decades. I imagine most moderate+ people have bought into the family planning concept. Yes the logistic equation predicts it could happen automatically too [1]. And no, collectively we've decided we don't want to find out for sure.

Some conservative confessionals just haven't bought into it. Because fair-or-not they might not buy into anything without a century of thought first.

This pretty much covers a big chunk of Tantaman's data from a different angle I think.

[1] All methods that study how priors shape what you explore.

[2] For instance: house, food, and fuel prices are signals for this kind of thing. I can imagine lots of conversations going "Can we really afford one more? We're up short as is!"

Reading further, I might be being too charitable.

Demographics are under government control, at very least at the dP/dt level. Much of the causality should be sought there.

Contraception, abortion access, immigration policy, tax incentives, childcare subsidies, parental leave, housing policy, education funding, propaganda. The levers are endless.

Until recently most governments were simply trying to level off their population. They may have succeeded a bit too well, but that's another story.

Somehow -in their essays so far- Tantaman has left out government policy almost entirely, which is a big elephant in the room to miss.