korrents

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We Actually Know A Lot About Fertility Decline

Lyman Stone · 20 Aug 2026 · lymanstone.substack.com ↗

5 korrents from this piece

Lyman Stone did not write this page.

Every claim below was made in this piece, quoted word for word and numbered in the order the piece makes them, so you can read it there rather than take our word for it. The sentence above each quote is our reading of the claim, not their wording. Each quote was checked against a stored copy of the page at build time; where the two differ, the quote is the fact.

  1. Our reading

    Calling the fall in birth rates a mystery is not humility but obscurantism: there is already a good causal account of it.

    Their wordswe really do have a good causal model of how to think about fertility decline!
    Interesting

  2. Our reading

    The global fall in births over the past two centuries is mostly explained by falling child mortality, and that part of the question is settled.

    Their wordsThe main cause of falling fertility globally over the last 200 years has been declining child mortality.
    Interesting

  3. Our reading

    The theory that birth rates fall because home life has not caught up with women's opportunities at work is not supported by the data.

    Their wordswithin societies, more gender-egalitarian people almost never have more kids than less gender-egalitarian people, and in a panel model, changes in the mismatch rate have no relationship to fertility
    Interesting

  4. Our reading

    Ruling out every measurable cause because none explains all the variation, and putting an unmeasured one in their place, is not an explanation.

    Their wordsHe ruled out all the actual, measurable variables because they were an imperfect explanation, and instead offers a vague, diffuse variable, for which he has no measure, and which is not actually included in his model.
    Interesting

  5. Our reading

    A model fitted only to trends in its own outcome cannot forecast anything, because it contains no variable anyone could change.

    Their wordsThe demand for explanations of low fertility is entirely a demand for variables which will reduce these technical trends to near zero.
    Interesting