Too early to declare a general law of social mobility and heritability for education (reply to Engzell and Tropf, 2019)

Engzell and Tropf (2019) find a positive association between intergenerational mobility and heritability for educational attainment. However, we cannot be confident of the relationship between these two variables until this question is revisited with: a) samples which contain data on both twins and their parents/offspring, b) models which precision-weight those samples, and c) models which test the consistency of the relationship across scientifically salient subgroups.