Greenland’s fertility rate change isn’t actually possible

I call data error.

Fertility rates are *lifetime* rates. It simply is not possible for a population where the women above 40 – just to use some age as an example – all had 7 kids to fall to an average for the entire population of 2.3 in only 8 years. Not unless someone’s gone out and slaughtered all the 48 year olds at least.

14 comments on “Greenland’s fertility rate change isn’t actually possible

  1. Looks like they’re taking annual birth rates and then some demographic maths to derive a ‘moment in time’ fertility rate.

  2. Pendantry or maybe just proper use of English – I always thought ‘fercundity’ was the correct term for number of children over a lady’s lifetime.

  3. The population of Greenland is 56,672 , lets say fertile adult women are about 19000 ( which would be about the right proportion I think ) that means last year , say the average gate at Watford FC
    Did they all have seven children ?
    Nope I`m lost that an`t be right ?

  4. Patrick beat me to it. This is a “rate” so the annual birth-rate expressed as the number of children a woman would have in her lifetime if, each year, she had the average number of children born to women of that age.
    The British birth-rate peaked in 1919 and 1946 and slumped in the 1930s, so we have had big swings but I suspect what happened in Greenland was the combination of great improvements in infant mortality which we experienced a century earlier and the introduction of cheap reliable contraception

  5. BiB: fercundity

    That’s about needing a wax, isn’t it? Perhaps fecundity’s more apt.

  6. How the hell are they able to declare a fertility rate for 2015, the women haven’t finished being alive yet.

  7. Life expectancy isn’t calculated on the basis of what anyone in particular is actually expected to live either, nor do you need to wait until someone born today has died to figure out what it is… think most demographic stats are calculated with the same philosophy, based on who’s been alive over the last year and how they’ve behaved, rather than looking over the lifetime of a particular person.

  8. @BiB – naughty autocorrect! I shouldn’t have made the observation except that it provided an opening for a slightly louche, if weak, joke.

  9. Seems an abrupt slowdown but the scaling doesn’t help looks like it dropped over the period 1961 to 1973

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