In this post we are going to take a look at the chess performance of Ashkenazim relative to other Europeans. Ashkenazim are massively overrepresented in the higher echelons of chess history, with almost half of all World Chess Champions having at least partial Ashkenazi ancestry. But of course, it is not a priori clear that this is the result of stronger chess playing ability on average.
Our data set has some clear sampling issues. Generally only relatively strong players are going to play rated games and the less developed the chess infrastructure of a country the more that is going to be the case. For example, the highest average rating of all countries is exhibited by Cuba. Cuba is a legit strong chess playing country with a World Champion (Capablanca) and some current very strong players (Lazaro Bruzon, Lenier Dominguez) to its name. But if we compare the rating distribution to the distribution of the USA, we see that the higher average is due to left part of the distribution missing, while there is still a gap at the right side.
In this figure we normalized the distributions by height. That’s not perfect, but it is probably better than normalizing by number of players, because that would over emphasize the right tail if the left tail is thinner due to under sampling.
For the Ashkenazim, we can partly circumvent that problem by comparing US Ashkenazim to all other US players. Then at least the chess infrastructure is the same, although a group with a lower mean might still be under sampled at the left tail possibly reducing the difference. This is also a high bar to clear for the Ashkenazim because the US has stronger rated players than comparable Western European countries.
We look at US players with a typical Ashkenazi name. We circumvent the problem discussed in my post „Counting Names“, by only considering names that also occur among Israeli players. This makes it unlikely that we pick up German, English or Spanish names that are also (but rarely) found among Ashkenazim.
The figure shows an Ashkenazi advantage both at the left tail and the right tail. Contrary to my assumptions it is bigger at the left tail. It might be the case that less Ashkenazim commit to high level chess due to a comparative advantage in other fields. That is for example very noticeable in Germany, where there is a strong chess infrastructure, a general high level, but almost no (native) chess professionals and consequently no international contenders.
With these caveats in mind, the average US Ashkenazi rating is 2014 while the average US non-Ashkenazi rating is 1924. A difference of 90 points or 0.40 standard deviations. In terms of IQ this translates to 106 which is not completely out of line with other cognitive measures, especially if one takes into account that the g-loading of chess is likely not very high.