This blog is intended to go along with Population: An Introduction to Concepts and Issues, by John R. Weeks, published by Cengage Learning. The latest edition is the 12th (it came out in 2015), but this blog is meant to complement any edition of the book by showing the way in which demographic issues are regularly in the news.

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Friday, May 8, 2015

New Fertility Trends in the U.S.

The U.S. Census Bureau recently made available the fertility data from the 2014 Current Population Survey, and Gretchen Livingston at Pew Research has undertaken a very thorough analysis of trends over time. The bottom line is that while period fertility rates in the U.S. have dropped a bit especially in reaction to the Great Recession, there is evidence that women who might not previously had a child are now having a child (i.e., childlessness is going down, not up), whereas larger families (4+ children) are rapidly leaving the scene. Thus, the long-term trend (the "quantum" effect) is essentially stable, even if the short-term trend (the "tempo" effect) has been slightly downward. And the trendsetters are women who have in the past led the decline in fertility.
Among women in the United States, postgraduate education and motherhood are increasingly going hand-in-hand. The share of highly educated women who are remaining childless into their mid-40s has fallen significantly over the past two decades.

Today, about one-in-five women ages 40 to 44 with a master’s degree or higher (22%) have no children – down from 30% in 1994, according to a Pew Research Center analysis of newly released Census Bureau data. The decline is particularly dramatic among women with an M.D. or Ph.D. – fully 35% were childless in 1994, while today the share stands at 20%. Not only are highly educated women more likely to have children these days, they are also having bigger families than in the past. Among women with at least a master’s degree, six-in-ten have had two or more children, up from 51% in 1994. The share with two children has risen 4 percentage points, while the share with three or more has risen 6 percentage points.
These are generally beneficial trends for the economy because a society that is just replacing itself--and with children in families with sufficient resources--is likely to to better off economically in the long run. This is generally where Scandinavian countries have been, in contrast to much of the rest of Europe, where fertility is well below replacement level, regularly prompting financial writers to worry about the economic impact of an aging population, especially in an environment where income from investments may not match the long-term pension needs.
Don’t you think that a drop in Germany’s population from over 80 million people today to 65 million in the next 30 years will matter next year? Of course it will, and the ageing process largely explains the very modest growth in domestic German demand at present, even if many prefer to blame modest consumer demand in Germany on the nasty experience the country went through in the 1920s.
This is just a reminder that demography underlies almost everything going on in the world. 


  1. Prof Weeks said - This is just a reminder that demography underlies almost everything going on in the world.

    Correct professor. And yet strangely enough, for the ordinary person on the street the effects of "demography" are subliminal at best. Our politicians and our media frame issues in terms of the "latest crisis". There is always some immediate cause-and-effect that appears to be causing the crisis. But the underlying demographic influence is rarely ever understood!

    Prof, Sterman at MIT wrote a very interesting paper recently. He was looking at why people do not understand climate change and carbon-dioxide levels. So he constructed a sample problem, with basic arithmetic, and asked the students to solve it. He provided all of the knowledge needed to get the answer. ALL that the students needed to do - was to realize that if a certain amount of carbon-dioxide is created in the atmosphere, it must all GO SOMEWHERE. In physics, we call this a "mass balance". Once the stuff is created (carbon dioxide), it cannot disappear. It must be somewhere in th system.

    Prof. Sterman discovered, to his great surprise that most of his graduates in management could not solve he problem that he gave them. Furthermore, many graduate students with advanced technical degrees also failed to solve it. So Prof, Sterman came away with the conclusion that human beings have a "cognitive gap". Our brains are not setup - to easily grasp some of these long-term global problems. We understand short-term cause and effect, but not the underlying reasoning.

    And I think the same thing is escaping the people of the world - in terms of how demographics is influencing everything. They are not perceiving the root causes of the global problems.

    Pete, Redondo Beach, CA

    1. Yes, as a species we tend not to want to do the heavy mental lifting. My older son (who has a PhD from MIT and is a professor of management) pointed me to a great book (previously on the NYTimes bestseller list and written by a Nobel Prize winning Princeton professor) that details this phenomenon: Daniel Kahneman, "Thinking Fast and Slow". I highly recommend it.

  2. Interesting. A small quibble: the phrase "just replacing itself" may convey an impression that the numbers of births and deaths in the U.S. are roughly equal, but that is not so: for example in 2011 there were 3.95 million births compared to 2.51 million deaths. (I realise you were referring to TFR=2.1 generational replacement rather than population replacement).

    1. Good point! You get extra credit for the clarification :)