Bryan Caplan  

Ancestry and Long-Run Growth Reading Club: Ask Me Anything

Brad DeLong's Distorted View o... Ancestry and Long-Run Growth R...
In the comments, Ask Me Anything about ancestry and long-run growth.  Tomorrow I'll do my best to answer every question.

P.S. Feel free to repost comments from earlier Reading Club entries.

COMMENTS (9 to date)
December writes:

What about the possibility that the distribution of traits may vary between populations due to genetic differences between populations? If it is those traits are driving long-run growth, and those traits cannot be easily copied due to their partial genetic basis, how does that affect the analysis you've been making in this series and your views on open borders?

[incomplete html fixed--Econlib Ed.]

Denver writes:

First off, I just want to say that I enjoyed the reading club, and I hope you do these again in the future, it was very informative.

While I tend to agree with your assessments, I do have one reservation. Most of these measures are simply looking at the ancestry of the populace, and correlating it with current levels of productivity. But what about institutional impacts? That is, what impact do you think ancestry plays in forming social norms and government policy? Which could then have these observable impacts in productivity.

For example, if ancestry measures were as predictive as anti-immigration advocates often imply, then we would expect to see homogeneous nations (in terms of ancestry), like Europe, outperform their heterogeneous counterparts: the US. On the whole, I tend to think the opposite is true: heterogeneity outperforms homogeneity.

However, if ancestry impacted institutions, and not merely productivity levels, we might observe this phenomena. While the US is significantly more heterogeneous than it's European counterpart, it's political landscape has largely been dominated by the same European ethnicity through most of it's history. Thus, while the US is more heterogeneous in terms of ancestry, it's institutions are still largely European, maybe even selectively so (as not all Europeans immigrated to the Americas).

While I think most arguments against the open borders movement are weak, I do think one of the more powerful arguments is that of "political externalities". While I suspect both you and I agree that these externalities are best internalized, we do live in modern democracies, for better or worse. So I have one final question: given the two options, open borders or open borders given that immigrants from backwards countries (measured by "SAT", IQ, or another relevant measure), and their descendants, are barred from voting, which would you choose?

Joshua Woods writes:

1. What seems to you to be the most promising avenue for future research in this area?

2. The addition of latitude controls drastically affected the coefficients on the various ancestry variables. Do you think this powerful effect of latitude holds today at our much higher technology level?

Thanks for doing this by the way.

Ben Wilson writes:

Has any objective research or even informed speculation been done on why latitude effects are so strong? Agriculture concerns would have been important in past centuries, but probably not so much in the past 50 years. Plucky New Englanders might suggest that experiencing the seasons sets our resolve to be more productive (or something).

Eric writes:

Question about your "The Equator in Comin, Easterly, and Gong" post:

It doesn't look like the distance from equator metric, or any of the other geographical controls, are migration-adjusted. So the correlation could be due either to geography having an immediate effect, or to populations being affected by geography only over a long period of time. In the latter case, the long-term effects of migration might be the same, but the short-term benefits might be much smaller.

Do you think the results would be much different if you looked at current location controlling for location of ancestors? Has enough data been released to do that analysis?

Richard writes:

I second the question about genetic differences.

Furthermore, do you think that the authors ignored the genetic argument for political reasons?

E. Harding writes:

Caplan, what would be the minimum evidence needed from this and suchlike research for you to be convinced that Open Borders is inferior to the Status Quo?

John Alcorn writes:


Might you address the the first set of comments by David Weil, about your blogpost on Putterman & Weil (2010)?:

1) The big issue that you want to address is what we learn about the economic effects of free immigration (a policy of open borders applied to the US today) from the PW analysis of historical migration. The PW finding is that the higher the fraction of the population of a country that is made of of people descended from early developing countries, the richer the country is, on average. From this, it seems like one could conclude that adding a lot of Syrian refugees to the US would make the US richer, since Syria was one of the earliest developers (using either of our measures).
I think drawing such a conclusion from our data is unwarranted, for several reasons.

First, the data just show correlations, not a structural relationship. For example, places with lots of descendants of Europeans (high state history) tend to be rich. That might be because the Europeans made them rich, but it might also be because Europeans went to places that had good characteristics. One could imagine an experiment of sending migrants randomly to different places in different proportions, then waiting 500 years to see how things came out, but that is not what happened.

Second, the environment in which migration would be taking place now is just completely different from migration historically. Most of the Africans who came to the New World did so as slaves on sailing ships; how could we learn from that experience what the economic effects of Africans coming as voluntary migrants on airplanes, into modern welfare states, would be?

Third, beyond the nature of migration, the whole world is very different. For example, when Europeans migrated to the Americas, they brought with them productive knowledge and ideas about the structure of society that could not have been transferred by any means other than migration. That is no longer the case.
All of this is not to say that open borders are a good or bad policy -- simply that the historical experience examined by PW is not a good place to learn the answer.

You observe that (a) long-distance migration is rare, (b) long-distance migration is bimodal, and (c) large-scale, civilized (voluntary, peaceful) migration is an extreme historical rarity. Those observations would seem to reinforce Prof. Weil's point that long-run historical evidence provides little guidance for policy debate about open borders. What do you think?

Jon writes:

Being statistically illiterate, I expect I'm just confused, but I got the impression that at least some of the ancestry research was was interpreted to show that institutions don't matter, or, don't matter very much. That seems implausible to me, if only because of the contrast between North and South Korea. Can someone please straigten me out? Thanks.

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