I just wanted to offer one
correction and one further quick comment.
You wrote: "How could one
even begin to construct such a matrix? Whenever possible, P&W use
actual genetic data, then supplements genetics with history." For better
or worse, this isn't really the case. We rely heavily on heroic assumptions
that unless identified by sources like the ones mentioned in our appendix such
as Everyculture.com, Countriesquest.com, Encyclopaedia Britannica, World
Christian Encyclopedia, etc., people living in a country conventionally assumed
to be fairly ethnically homogeneous, e.g. France or Spain, are descended from
people of that same country. The sources do mention migrants, for instance
Algerians in France, but there may well be an undercount of mobility of the
presumptively French population, who could well have ancestors who crossed what
is now a border with Germany, Italy, Spain, or even a couple of borders (from,
say, Poland) sometime in the 500 years ending in 2000. (We have to hope that
such migration doesn't make a big difference, as descendants will in the
meantime have perhaps become for all practical purposes like those with only
ancestors within current French boundaries during that half millennium.) We
used sources based on genetic studies only to get estimates of the regional
ancestries of populations described as being of mixed origin, e.g.
"mestizos", in those same sources, and only for countries having a
large share of such people, 30% or more, for instance Mexico. The method is
described on p. 1632 of our paper, and I think I can see how your misunderstanding
might have arisen based on the first sentence on that page: "whenever
possible we have used genetic evidence as the basis for dividing the ancestry
of modern mixed groups that account for large fractions of their country's
population." As you can see from a closer reading, we do this only for
mixed groups such as "mestizo" "mulatto" etc. and only when
they are a large fraction. The extant DNA studies mainly attempt to pick up
differences between long separated populations, such as sub-Saharan Africans
and Europeans, but not between members of populations that haven't been as
separated, like Germans and Italians.
My other comment is that you
write that "civilized migration - where people voluntarily move to a new
country to peacefully improve their lives - is an extreme historical
rarity." We don't take any definite position on that, but off hand it
seems wrong and we didn't mean to suggest it. Although there was a lot of
forced movement of Africans to the New World early on, there was overall even
more voluntary movement to the Americas, mostly of people from Europe but also
ones from other regions, and likewise large parts of the overall migration to
places like Australia, New Zealand, South Africa, Singapore, and Taiwan was
voluntary on the parts of the migrant. Whether these arrivals were
welcomed by the original inhabitants (Native Americans, indigenous Australians
and Taiwan indigenous peoples, etc.) is a whole other story.
By the way, regarding state
history working well with 5% discounting, I believe we tested a bit and found
it relatively insensitive, so we used the discount that had been applied in
other papers. It does turn out that if one lacks back to years before 1 CE,
some results become more sensitive to discounting. Borcan, Olsson and I have a
working paper in which we report state history for roughly the same number of
countries, but going back to the first states, in Mesopotamia before 3,000 BCE.
We find that current GDP is concave in this longer-term state history
especially when using a low discount like 1% so that the more ancient periods
still get non-negligible weight; by concave, I mean that the oldest states such
as Iraq are predicted to have lower GDP than "middle aged" ones like
England and Germany.
1. I did indeed overstate PW's reliance on genetic data. My mistake.
2. I included the word "peaceful" in my definition of "civilized
migration" to exclude migrants who took the land (and often lives) of the
existing inhabitants. Voluntary on the part of the migrant isn't
enough. Of course, there's a continuum. But European colonization
was largely predicated on military conquest, unlike immigration as we usually conceive it today.
3. Thanks for the details on the state history discounting.