Open Thread 1-7 June | 175 comments (175 topical, editorial, 0 hidden)

I have a hard time believing those figures.

Even defining "women" as "women over 20" or so, and rounding down to 55, that is still 3.3 children per woman, in other words a runaway population increase. That does not seem right.

Earth provides enough to satisfy every man's need, but not every man's greed. Gandhi

by Cyrille (cyrillev domain yahoo.fr) on Thu Jun 4th, 2015 at 10:47:46 AM EST
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Re: Population Doom (none / 0)

I looked up the CDC source. Apparently, they mean "births per 1000 women aged 15-44 years".

The map is for the year 2011.

by das monde on Thu Jun 4th, 2015 at 09:54:42 PM EST
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Re: Population Doom (none / 0)

In other words, you cannot distinguish real effects from artefacts of the age distribution of women of childbearing age.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Fri Jun 5th, 2015 at 04:04:22 AM EST
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Re: Population Doom (none / 0)

What does this alter in the relative comparison? I was just paying minimal attention to the statistics specification.

by das monde on Fri Jun 5th, 2015 at 04:18:25 AM EST
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Re: Population Doom (none / 0)

You can easily get a factor of two in either direction.

Quantifying the effect in this particular case would require me to go dig around in BLS databases for an hour or two, which I don't feel like doing right this moment.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Fri Jun 5th, 2015 at 05:55:34 AM EST
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Re: Population Doom (none / 0)

Do not see what you still need.

The "replacement rate" of 2.0 children per women corresponds to 66.7 for the map data (=2.0x1000/(30 years)) - right in the gap between the blue and red numbers (apart from Hawaii).

by das monde on Fri Jun 5th, 2015 at 06:27:47 AM EST
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Re: Population Doom (none / 0)

Imagine a contrived scenario where all women have twins sometime during their 30th year of age, and no children in any other age bracket.

Now imagine that you have two states, one in which all the women are 29 years old, and one in which they are all 28 years old.

Now tell me what the absolute birth rate would be in those two states.

Now tell me what the absolute birth rate would be in the following year, for both states.

For extra credit, calculate whether the states in this example are over or under the replacement fertility.

In the real world, of course, both the demographics and the fertility distribution by age are much messier than in the nice, clean example above. Hence the need for spending an hour or two poking about in BLS data.

- Jake

Friends come and go. Enemies accumulate.

by JakeS (JangoSierra 'at' gmail 'dot' com) on Fri Jun 5th, 2015 at 08:02:19 AM EST
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Re: Population Doom (none / 0)

A long river in Egypt comes to mind.

by das monde on Fri Jun 5th, 2015 at 08:19:05 AM EST
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Re: Population Doom (none / 0)

The Mississippi?

_{It is rightly acknowledged that people of faith have no monopoly of virtue
- Queen Elizabeth II}

by eurogreen on Fri Jun 5th, 2015 at 09:58:49 AM EST
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