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One of the most innovative ways to estimate the IQ’s of Nobel Prize winners (and other elite groups) has been to observe the percentage that are Jewish (or partly Jewish). Since high IQ is disproportionately common among Ashkenazi Americans, any achievement that selects for high IQ should also indirectly select for Jewish ancestry, so all else being equal, there’s some mathematical formula that allows ones to estimate a group’s average IQ from the degree of Jewish over-representation. Such calculations have been done by La Griffe du Lion and others.

La Griffe argued (if I understood him correctly), that since U.S. Nobel Prize winners and Americans with IQ’s of 139+, are both 27% Jewish, that the dumbest Nobel Prize winners has an IQ of 139, and from there he concluded that the average U.S. Nobel Prize winner has an IQ of 144. While an average IQ of 144 sounds plausible, La Griffe’s methodology made no sense to me because the IQ’s in a group (even a high achieving one) tend to be normally distributed, so I would expect a wide range of IQ’s rather than everyone bunched together above some ridiculously high threshold. So now would be a good time to revise his analysis with a radically different approach.

The correlation between IQ and Ashkenazi ancestry

Ashkenazi Jews are 2% of America and average IQ 113 while the average for all Americans is 100. If there were a perfect correlation between Ashkenazi ancestry and IQ, every single Ashkenazi American would be in the top 2% of IQ (130+) and thus the average Ashkenazi American would be in the top 1% (IQ 135). Since the average Ashkenazi American is not 35 points above the U.S. average, but rather 13 points above it, the correlation between Ashkenazi ancestry and IQ can be estimated by dividing 13 by 35, which gives 0.37. Of course this correlation falsely assumes that Ashkenazi ancestry is a normally distributed continuous variable that all Americans can be ranked on, when in reality it’s a discrete category that only a small minority fit into, but for our purposes, that probably doesn’t matter.

The correlation between g (general intelligence) and Ashkenazi ancestry

If Ashkenazi ancestry correlates 0.37 with IQ, and most IQ tests have a g loading around 0.85, then dividing 0.37 by 0.85 gives the g loading of Ashkenazi ancestry as 0.44. We should also correct for the fact that ethnic self-identification probably correlates about 0.9 with actual ancestry, so dividing 0.44 by 0.9 reveal the true g loading of Ashkenazi ancestry to be 0.49.

How Jewish are Nobel Prize winners?

According to this source, Jewish Americans are dramatically over-represented among U.S. Nobel Prize winners. They are 11% of Peace laureates, 27% in chemistry and literature, 38% in physics, 42% in physiology and medicine, and 53% in economics. Since only 2% of the general U.S. population is Jewish, these numbers imply that peace prize winners are 0.8 standard deviations (SD) more Jewish than average, chemistry and literature winners are +1.4 SD in Jewish ancestry, physics winners are +1.67 SD, physiology/medicine +1.8 SD, and economists are +2.07 SD

Estimating average IQ from average Jewish ancestry

In order to estimate the average IQ of the Nobel Prize winners, we must divide their degree of Jewish ancestry (expressed in SD units) by the g loading of true Jewish ancestry (0.49). We must then multiply the resulting Z score by 0.85 since that’s the g loading of a typical IQ test. After multiplying the Z score by 0.85, we multiply it by 15 and add 100 to convert to the IQ scale.

The smartest Nobel Prize winners are economists?

After doing the above calculations we get the following average IQ for Nobel Prize winners in different disciplines:

Economics: Average IQ 154

Physiology & Medicine: Average IQ 147

Physics: Average IQ 143

Chemistry: Average IQ 136

Literature: Average IQ 136

Peace: Average IQ 121

These numbers sound plausible. The only red flag is that physics laureates didn’t rank higher. I suspect that’s because Ashkenazi intelligence is verbally oriented, so using Ashkenazi ancestry as a proxy for IQ underestimates the ability of spatially oriented intellects. Had this analysis been done based on East Asian ancestry instead, physicists may have come out on top.