Sunday, April 02, 2006

US Fertilty and Growth, A Research Agenda

by Edward Hugh

Possibly some could accuse me - and probably with good reason - of being obsessed with the US fertility issue (see this post which was a first pass at the issue, and this one by Claus). I think what is happening on the fertility front in the US is important for all of us since the US fertility situation is more or less unique in the OECD world, and possibly will become even more unique as an increasing number of developing countries attain below replacement (and possibly even lowest-low) ferility. The examples of the Asian tigers, China, Thailand, the Southernmost (and economically most succesful) Indian States (Kerala, Tamil Nadu) should give us serious food for thought on this count.

The US has managed, to date at least, to maintain something approximating to replacement fertility, the big question is why? The US is also (along with France and the UK) well-known as having been a host country to substantial migratory in-flows, and of course France and the UK also to-date have relatively more benign structural damage to their population pyramids. So the first question that one might want to ask would be what precise connection there is between migration and fertility?

Following on from that, the decline in fertility has been slow and long term in all three of these countries (France, the Uk and the US), so is there any connection between the slow decline and the absence of very low fertility? This would be my second question.

Also we know that those OECD countries experiencing above average growth (the US, Spain, the UK) are experiencing strong inward migration, while the higher median age societies (especially Japan and Germany) are now seeing very low net inward migration or even net outward migration. In addition the skill balance of these flows in the oldest-old societies is strongly negative. Inward migration is largely unskilled while a more highly educated and skilled population may be leaving. Are we, then, seeing non-linear consequences of overly rapid ageing in some societies while the problems posed by negative migration and fertility traps are looming in others? This would be the third question.


S.M. Stirling said...

The important thing to note with the US is not that it's "maintaining" replacement-level fertility, but that it has a long-term _increase_ in its fertility level.

European and American fertility rates tracked each other fairly closely up until the late 1970's or early 1980's, though American rates were usually a bit higher.

However, since then the American population (apart from the minority groups) has shown consistent, if slow, increases in TFR.

Janet Baker said...

I wonder where SM Stirling is getting those figures on fertility level. The US Census bureau site says that the US Growth Rate is projected to slow very significantly between 2030 and 2050. The population increase in this comment must refer to total number of population, which is expected to grow. Could someone comment on first, the definition of fertility level constrasted to growth level? If they are the same, would Stirling care to comment on the discrepancy between his figures here, and the US census bureau?