Approximately 15-25% of everything we know about global fertility comes from basically one source: the Demographic and Health Surveys.

The contract funding them seems to have been cancelled.

If you're worried about falling fertility, this is a five-alarm fire. This piece is cowritten by me and @MoreBirths . Our take here is basic: the DHS surveys are a well-run program yielding very clear benefits to the U.S. and are a key tool we have on hand to figure out how to tackle low fertility.

Losing this tool is not good at all.

raising retirement age reduces fertility

there's a TRADEOFF between "adapting" to demographic decline and "solving" demographic decline!

many strategies that help societies cope in the near term make demographic balances worse later on. when grandmas have to work later in life, they provide less childcare

Today at @FamStudies we released a new study of almost 9,000 reproductive-age Americans showing that the only path to a more family-friendly America is opening up new land for single-family housing (thread).

https://twitter.com/SecretaryTurner/status/1901634637606035462

The heart of our study is this graph, which shows the results of a randomized forced-choice (conjoint) experiment where respondents had to choose, between different housing options, in which they'd be most open to having (more) kids.

are turkish nationalist types aware of how massively homosexual the ottomans pre 1600 or so were? like is this on their radar? have they ever read ottoman love poems? which are literally 95% about little boys?

i'm genuinely curious how aware modern turks are of this we have ottoman sex manuals written for royals and they run on about how excellent it is to have sex with little boys for multiple chapters

Today the @guardian has a piece out saying that @natalismorg is a conference for fascism and liberal eugenics.

It does include fascists and liberal eugenicists. I abhor and detest both ideologies, and it's insane to act like that's the range of ideologies represented. Knowing many of the speakers listed, I know many of them don't support *any* variety of eugenics, myself included. Many of us are very publicly on record publicly condemning the entire eugenic/dysgenic framing of fertility change!

How can we raise fertility?

Today, I and 3 awesome coauthors have a new paper out at the Journal of Population Economics where we show that a huge part of the story has to be ELITE LEADERSHIP.

When one Kartvelian elite decided to change his country, he succeeded. For years, I've been saying that the Georgian Orthodox Patriarch boosted his country's fertility by using his superstar status to motivate extra births through a campaign to personally baptize higher parity babies.

I had some evidence, but there were always some skeptics.

the Good Samaritan is a story in which a Levite and a priest de-prioritize the needs of their physically close neighbor in order to do the abstract good of maintaining purity for physically non-proximate neighbors

let the reader understand okay i will spell it out for the reader:

the Levite and priest downrate the nearby injured man, plausibly to remain ritually pure, they have duties elsewhere, people who need them more.

the Samaritan says, screw the abstract distant need, this person is right in front of me

i am sympathetic to the libertarian paranoia about government surveillance

but then i meet actual libertarians and i realize

they are doing significant crimes at alarming rates and should in general be surveilled my proposal: a sweeping program of surveillance but only for people who complain about it

Why is fertility declining in rich countries?

Last week, I said it was actually very simple: nobody's getting married.

Today, @jburnmurdoch has followed where that thread leads and shows that around the world, coupling is crashing, and where coupling falls, so do births.
My post laying out the long-and-short run drivers of falling fertility is here:
substack.com/home/post/p-15…

Link to the new FT piece is here:
ft.com/content/43e2b4…

What explains the rise of Christianity?

Was it because we were so nice that everybody converted?

In a new post responding to Astral Codex Ten's recent pieces, I argue, no. Christianity won because we had babies and killed infidels. The details on low pagan fertility are paywalled, sorry. Workin on a book about it, gotta get paid.

But here's a fun graph of Egypt's religious history.

When Constantine came to power, Egypt was already >33% Christian.

The @nytimes has a striking piece on intimate partner homicide during pregnancy. It's a terrible tragedy.

They also don't seem to actually present any data on it. Look at these charts and see if you can spot what's missing.
First, obviously, none of the actual data shown indicates the person committing the homicide was a partner. Undoubtedly, much of it was! But it's not easy to guess how much of it.

What happened is NHANES changed their sample.

Here's the data by age of man with standard errors, 1999-2023. You can see from the big standard errors in 1999 and 2003, and the incorrect age gradient in 2003, that the early samples were small and perhaps unreliable.

https://twitter.com/AlpacaAurelius/status/1862912099665494484

The NHANES documentation does change between the 2003/04 and the 2011/12 editions for the lab methods section on sex hormone assays, but I'm not science nerd enough to know if it was really a substantive change.

But what I can say is sample size changed massively:

There are not many places on earth where we have detailed cause-of-death data from before the era of widespread vaccination.

Massachusetts is one of those places.

From 1842-1877, 70% of all deaths were from diseases which we today have vaccines to prevent. cc @RichardHanania this feels like it's up your alley

huge pain in the butt to hand-copy all these historic vital stats, but I did it a few years back and have never regretted it!

the cost to raise a child is approximately:

Annual individual consumption * Years Child Remains Dependent

in industrialized countries, AIC can be proxied using something like GDP per capita, and years-dependent is now approximately 20-30. call it 24. note that the approximation in the formula is based on more careful calculations from the small list of countries we have data from on actual parental spending, government spending on kids, parental time use, motherhood earnings penalties, etc

it's an all-in cost

Today @Noahpinion says nobody knows how to stop falling population.

That's not true. We know how. People just don't want to do it.
noahpinion.blog/p/nobody-knows… Subsidize marriage. Shorten educational timelines. Subsidize fertility. Educate people about their fertility. Publicly celebrate parenthood. Offset retirement penalties parents face.

It's clear that @propublica 's strategy is to spam stories of alleged deaths due to abortion bans, and never actually engage with any of the arguments about how they're actually running a cover operation for medical negligence. From the latest one.

They want to blame Texas' abortion ban for a hospital sending away an actively miscarrying women WHO ALREADY TESTED POSITIVE FOR SEPSIS.

Finland's fertility is falling fast.

But why? What's the source of this decline?

To begin with, some basic facts: Finland's total fertility rate was around 1.87 children/woman as recently as 2010. It did NOT decline during the "great recession" after 2007, but actually ROSE.

Since 2019, Finland's fertility has bounced around a lot, but the decline 2019-2024 was just 0.08 children per woman, vs. the decline from 2014-2019 of 0.36. So clearly the pace of decline has slowed, even if not stopped entirely.

But you may wonder: what drove Finland's decline? Did big families get rarer, or did people stop having families at all, or what was it?

Here's parity-specific birth rate indicators:
You can see they all decline after 2010. Here's each indicator, its 2022 value expressed as a ratio of its 2010 value:

You can see that 3rd births rates fell the most, down almost 30%, then 1st birth rates, down about 27%, then 5th, then 4th, then 2nd, down about 15%.

But they're all down. Finnish women became less likely to have an extra birth at every single parity.

What does this look like in terms of total birth count?

Well, it looks like appreciable declines for every birth order. And indeed, births fell 25-33% at every parity.

So did Finland's fertility decline because of a broad-based shift away from kids across all families? Perhaps!

But now let's ask this another way:

Comparing 2010 to 2022 births, what share of the decline in births was 1st vs. 2nd vs. 3rd, etc?

37% of the decline is due to lost first births, 36% second births, 17% third births, 5% fouthr, and 5% 5th+.

So more than a third of the total decline was due to a drop in first births, and more than half was due to a drop in first or second births. Low-parity births accounted for the lion's share of decline.


I think some open questions in the Finnish case are:
1) Why was Finland so resilient to the Great Recession?
2) Why the drop then at 2010?
3) Why was the drop so broadly shared across parities?

It's possible to be more wrong than this.

But you'd have to really work at it!

https://twitter.com/datepsych/status/1851989863580709244

Let's do some math!

We'll use a case of a country we have a long history of high quality data for: Czechia.

Czechia is also interesting because they've had one of the biggest fertility INCREASES in the industrialized world in recent decades.

UN, IHME, VID, all produce population forecasts- and they always seem too optimistic. Human population will start declining much earlier than the UN expects.

This has been obvious for a long time. @jburnmurdoch is right to highlight it--

But why does the error persist?
🧵🧵
You can actually see a defense of the UN's method here:


TL;DR-- the UN's method really is the best-performing forecast method in historic data compared vs. other structural forecasting methods.pnas.org/doi/10.1073/pn…

Just finished talking on a panel for a nice @BrookingsInst event about REMOTE WORK AND FERTILITY.

Here's a finding I haven't published anywhere on remote work and fertility across 8.6 MILLION employed women in the ACS. Remote-working women have WAY higher birth rates!!! Link to the @BrookingsInst panel is here: brookings.edu/events/could-a…

oh hey the Clark-style malthusian model of the medieval english economy may be totally wrong Source: sciencedirect.com/science/articl…