Throwing a bit of light on a very vexed issue. The data and the subsequent quote are both from “What’s Your Major”: Another Blow to the So-Called Gender Pay Gap.

Ph.D. Fields of Study With the Highest Gender Weighting

“Most Female”                             “Most Male”
Art History                           Aerospace Engineering
Psychology                          Mechanical Engineering
French                                 Electrical Engineering
Comparative Literature               Physics
Sociology                                Computer Science

The study goes further and lists which fields of study tend to be “most male” or “most female,” meaning fields in which the gender imbalance is the greatest. One must have lived under a rock not to know that so-called “STEM” fields are in great demand and pay well in the marketplace. Lo and behold, all of the “most male” fields of doctoral study are in the STEM fields, including Aerospace Engineering, Mathematical Engineering, Electrical Engineering, Physics, and Computer Science. . . .

Ignoring how fields of study differ by gender is only one problem with the supposed 20% gender pay gap. The 20% figure ignores that men tend to work longer hours, to have more years of work experience, and to work in jobs that are more physically and financially risky than women. After accounting for these factors the unexplained portion of gender pay differences – the part that could potentially be explained by discrimination — shrinks significantly. Factoring in differences in fields of study, which exist not only at the Ph.D. level but in undergraduate and Master’s-level education as well, would shrink the potential range of gender discrimination even further.