Problems with a Causal Interpretation of Polygenic Score Differences between Jewish and non-Jewish Respondents in the Wisconsin Longitudinal Study

Dunkel et al. (2019) observe higher MTAG polygenic scores for educational attainment among the 53 Jewish respondents with available genomic data in the Wisconsin Longitudinal Study. They interpret their ensuing analysis as evidence that genetic differences "mediate" the association between being Jewish and higher cognitive test scores and higher educational attainment. We demonstrate instead--and perhaps counterintuitively--that the difference between Jewish and non-Jewish polygenic scores are much too large for their analysis to offer any evidentiary value for this conclusion. Instead, the data show clear evidence of the problems with comparing polygenic scores across ethnic groups that others have noted.