I suspect the fact that it's very densely populated and extremely expensive to live in has more to do with it. Couples can generally only afford to move out into their own apartments in their thirties, and the ancillary costs of schooling (tuition etc) if you want your kids to succeed rack up so fast that few can afford more than 1 or 2.

> Couples can generally only afford to move out into their own apartments in their thirties

It's also a cultural thing. Most people can afford to rent in their twenties, but plenty of families discourage it.

Subsidised public housing is available to married couples, and to singles 35 and above — but the wait time for new public housing with a 99-year lease is 3-4 years [1], which probably also affects the birth rate.

[1] https://www.hdb.gov.sg/cs/infoweb/about-us/news-and-publicat...

Why did you choose those two variables out of dozens of others?

If it's 'control' then why is birthrate high in many dictatorships? If it's apartments, why is birthrate decent in many ex-soviet countries full of apartments?

Lack of birth control maybe? Or relatively uneducated women?

Correlation != causation. I expected HN readers to know that.

GP said it seems, and just because correlation doesn't imply causation doesn't mean everything that correlates literally cannot have a causal relationship.

In other words... just because there's a correlation between things being correlated and things not being causally related, that doesn't mean that correlation causally implies acausality?

The default mode when operating with data is to assume there’s no causation. Doing otherwise creates room for too many misconceptions and erroneous interpretations.

Clearly you can make a hypothesis though.