As part of the undergraduate population analysis class we obviously took a look at fertility calculations. I brought in some data for the class to look at after consulting a bit about which states to choose. A big theme had been social norms and behaviors and how they can, can mind you, show up in data about fertility.
It was a really great discussion (at least I thought so). One of the interesting things with the class has been the build up to the North Dakota Population Projection I am working on, and fertility is obviously a key component there.
Taking a look at the states from class there was clearly a downward trend for several of the states, though interesting enough North Dakota did not, until the very end, exhibit much of a downward trend.
So for those not familiar with this calculation divide the numbers by 1,000 and you would get the average number of births per woman over their reproductive lifetime. Births at 2,100 is considered the replacement level, that is the current generation of parents replaces themselves completely with a new cohort if that is the level. You can see that from 2003 on Alabama and Massachusetts were below the replacement level the entire time, Massachusetts way below. California was right around the replacement level and then took a significant drop towards the end of the range. Given California’s status as an enormous population state the importance of that state dropping well below the replacement rate has important implications for the national total fertility rate.
Utah stays above the replacement rate for the entire span of years, though the trend is clearly down for them and it will be interesting to see if there is a moderation of the decline as it hits replacement. North Dakota stayed right around replacement for the entire interval with a bit of an increase towards the closing third that dropped off as well. If I had to guess, and I am actually researching the issue, I would suggest that the changes then are highly correlated with oil prices. Once again though the level seems pretty stable for the most part over that time period.
National concerns about fertility are in the news on a pretty regular basis right now. The graph shows that state level experiences are highly variable though. I think it remains an open question whether there are really policy options available to influence this outcome. With the TFR around replacement I asked the students why North Dakota still have population concerns, as in low population issues. Migration is clearly a big contributor, specifically outmigration of those born in North Dakota. Identifying that aspect of the problem does not necessarily make policy options any clearer.
I suspect significant concerns about economic prospects and other issues would be a part of an out-migration decision in North Dakota like it is with most other geographies. Do you have the financial resources to be competitive in that regard? And over a long enough time period to make a difference? This is a policy area where I think the questions are opaque, making it exceedingly unlikely that you can come up with clear answers.