On fertility rate and being careful with facts

Of late I have been looping Tyler Cowen's podcast "Conversations with Tyler" into the mix of things I've been listening to. Cowen is an interesting figure, definitely not toeing the line with anyone's orthodoxy of anything, really pretty much a polymathic egghead. Really smart guy who has produced a lot and has many interesting thoughts.

So I was surprised last week when, in conversation with Ezra Klein about the latter's most recent book on abundance, he said that the United States's fertility rate (the number of children women have on average over the course of their lives) had been at replacement rate (2.1) before the pandemic. That did not accord with my recollection, so I decided to look it up.

Here's what the St Louis Fed's FRED data bank shows (click on image to expand):

As I had recalled, the US fertility rate has in fact been below replacement rate since just before the financial crisis. Even more interestingly, what we see here is that since the Nixon years, US fertility has only inched above replacement rate momentarily, that moment just before the financial crisis when the whole world was zooming on a combination of the sugar high of credit expansion and the long commodities and economic liberalization boom ushered in by Deng Xiaopeng in China, Narasimha Rao and Manmohan Singh in India and, to a lesser extent, the opening of Eastern Europe post-Gorbachev.

Which further complicates the story of America's economic dynamism from Reagan (credit must be given for his cheerleadership) forward. If we have been below replacement rate for substantially that whole time the entire portion of our economic growh which is population growth as opposed to productivity growth must be put down to immigration. Certainly much interesting in our cultural life also has come from newcomers to our fair land, though regional renaissances (think Bill Neal and Crooks) have also helped.

Certainly it's a complex story and it obviously doesn't ultimately come down to "all immigration is good." But overall what I see leads to me to believe that immigration is net positive by a long shot.

Back to Cowen for a second. He has said that we should "write fot the AIs" which I have interpreted as an echo of Public Enemy's classic line "you can't copywrite a beat." We need to just be fruitful and get ideas out there and not worry about maintaining ownership of their economic potential. As I say this I have to admit to myself that another expression of the same idea is seemingly illegal immigrant Elon Musk's contention that patents are for the weak.

All the same, when we are in the public sphere and in positions of influence it behooves us to get our facts right as often as possible.