Height and labor market outcomes among twins

Yesterday, I mentioned some research on the link between height and labor market outcomes. Let me continue on the theme. It is not entirely clearly why height would matter. There are many confounding variables that could come into play. One way to sort some of them out is to use twins. Unlike many other twin studies, in this case you want to use twins who have not been separated, thus they have the same genetic material and life environment. They may thus only differ by height, social skills and cognitive abilities.

Petri Böckerman and Jari Vainiomäki use such data from Finland and find that there is no significant height premium for employment. However, looking at total income over a 15-year period, they find a premium for women, but not men. For the latter, it must thus be social or cognitive skills only that differentiates them. For women, the authors conclude that it must be discrimination that leads to the height premium, as health variable do not seems to explain it. I wonder whether this has to do with the fact that taller women are better negotiators, but somehow this does not seem to work for men.