Gender differences in fields of specialisation within economics

Following on from yesterday's post about simple information interventions to close the gender gap in economics, the same AEA Papers and Proceedings issue had a couple of articles on gender differences in the field of specialisation within economics, which are worthwhile considering. The first was this article by Nicole Fortin, Thomas Lemieux, and Marit Rehavi (all University of British Columbia), and looks at:

...the placement outcomes of nearly 5,000 economics PhD graduates from 82 US and Canadian institutions ranked among the top 200 in the RePEc rankings who have sought employment through Econ Job Market... between 2010 and 2017...

Their decomposition analysis first shows differences in the types of jobs that PhD graduates of different genders choose, specifically:

...that the largest and most significant gender differences are for research positions.. the combination of assistant professors and CB/MDB positions, where we find 61.4 percent of men versus 55.3 percent of women. Conversely, 11.8 percent of women versus 9.7 percent of men accept postdoctoral positions, and 24.2 percent of women versus 20.5 percent of men are in other nonacademic positions.

There are also substantial differences in the field of specialisation, where Fortin et al. find that:

Women appear to be crowding into a few fields where there are limited positions available. Women are concentrating in the traditionally female fields of health, education, and welfare (I) and labor and demographic economics (J): 28.9 percent of women versus 16.7 percent of men are in these fields...

Women are underrepresented in fields such as macroeconomics, monetary economics, and finance, which have better employment prospects because of more positions outside of academia.  

That isn't too surprising, and accords with earlier research, and also with the second article, by Eva Sierminska and Ronald L. Oaxaca (both University of Arizona), which used data on the fields of nearly 7500 graduate students and nearly 4500 faculty from across 385 universities in the US and overseas. First, looking at students who defended their PhD between 2009 and 2018, they find:

...gender differences in specializations are statistically significant in four fields. Women are more likely to be present in labor/health by 13 percentage points and less likely to be in econometrics, micro, and macro/finance by 2, 3, and 6 percentage points, respectively.

Then, looking at faculty, and separating their results by the year that the academics' PhDs were granted, they find that:

Among those who have completed their PhD prior to 1989, gender differences in specializations are statistically significant in five broadly defined primary fields: econometrics, labor/health, macro/finance, development/growth/international, and other. Women are underrepresented in econometrics and macro/finance (by 2 and 9 percentage points, respectively), and they are overrepresented in labor/health (by 14 percentage points) and other fields (by 3 percentage points). In this earlier period, women were also underrepresented in development/growth/international by 2 percentage points (in later cohorts, they were over represented).

Gender differences in these fields continue to be significant for more recent PhD graduates (except in other). In the group of academic economists who completed their degrees during 1990-2003, an underrepresentation for women occurs in micro by 4 percentage points. The gaps in labor/health and macro/finance slightly diminish (by 1 percentage point).

In the most recent sample of academics, those who completed their degrees between 2004 and 2016, the gaps continue to exist in the same fields and in addition occur in industrial organization (2 percentage points).

So, there are clear gender differences in field of specialisation within economics, and those differences have been persistent over time. What isn't clear from these papers is what contributes to these persistent differences. To what extent is this simply a difference in research preferences (and research topic preferences) between men and women? To what extent is it driven by the fields of specialisation in PhD advisors, and gender matching in advising (more on a related topic in a future post)? Are there differences in the culture of the different sub-fields that make a difference (e.g. see here)? Answering these questions would help us to understand these differences in fields of specialisation better.