The comparative lack of socio-economic diversity in economics

I've written a number of posts on the large and persistent gender gap in economics (see this post for the latest, and the links at the bottom of that post for more). There is also a gap in ethnic diversity, with minority groups under-represented in economics as well (see this post, and the report it refers to). Apparently the gaps don't end there. This new working paper by Robert Schultz (University of Michigan) and Anna Stansbury (Peterson Institute for International Economics) looks at socioeconomic diversity, i.e. diversity in terms of parents' educational attainment.

Schultz and Stansbury use data from the National Science Foundation’s Survey of Earned Doctorates (SED), which covers virtually all PhD graduates over the period from 2000 to 2018 (over 470,000 graduates, of which a bit over 10,000 were in economics). Importantly, the survey collects data on parental education, and Schultz and Stansbury use this to categorise PhD graduates into three categories:

...those with at least one parent with a graduate degree (a master’s, professional, or research doctoral degree), those with at least one parent with a bachelor’s degree (BA) but no parent with a graduate degree, and those for whom no parent has a bachelor’s degree (this group includes those with a parent who has an associate’s degree or some college, is a high school graduate, or has less than a complete high school education).

Schultz and Stansbury then compare across 14 PhD fields (while separating economics out from the rest of social sciences) in terms of the educational background of the graduates. They find that:

Among US-born PhD recipients over 2010–18, 65 percent of economics PhD recipients had at least one parent with a graduate degree, compared with 50 percent across all PhD fields (and 29 percent for the population of US-born BA recipients over the same period). At the other end of the spectrum, only 14 percent of US-born economics PhD recipients in 2010–18 were first-generation college graduates, compared with 26 percent across all PhD fields (and 44 percent among all US-born BA recipients). This makes economics the least socioeconomically diverse of any major field for US-born PhD recipients. And its socioeconomic diversity appears to have worsened over time: while economics has consistently been less socioeconomically diverse than both the other social sciences and the biological and physical sciences, since 2000 it has also diverged from mathematics and computer science, the other two least socioeconomically diverse large PhD fields.

Their Figure 3 (reproduced below) summarises the changes over time. Economics is clearly higher than other fields in the proportion of PhD graduates with at least one parent with a graduate degree, and the lowest with no parents with a BA or higher degree, and the gaps have grown over time.

Schultz and Stansbury then undertake some regression analysis, and find that:

...even controlling for race, ethnicity, gender, BA field, BA institution, and PhD institution, economics PhD recipients are around 5 percentage points more likely to have a parent with a graduate degree as compared with the average US-born PhD recipient, and 5 percentage points less likely to have no parent with a BA or higher.

The raw coefficient without controls suggests a 15 percentage point difference in parents with a graduate degree, and a 13 percentage point difference in parents without a BA or higher. So, even after controlling for race, ethnicity, gender, BA field, BA institution, and PhD institution (all of which make some difference), about one-third of the gap in socioeconomic background (as proxied by parental education) remains unexplained. The question that raises, is, why? Schultz and Stansbury suggest four possibilities:

1. The complexity of the path to a PhD in economics, due to the need for students to meet high-level mathematics pre-requisites to get into a PhD programme in economics;
2. Disparate access to professional relationships, due to a lack of social capital, implicit or explicit bias from faculty, or mentoring relationships that tend to develop along sociodemographic lines;
3. Financial circumstances and incentives, wherein students from lower socioeconomic backgrounds face high opportunity costs of PhD study; or
4. The orientation, culture, and practice of economics as a discipline.

The second and third reason seem unlikely to me, and the complexity of the path to a PhD in economics may be true, but it is unlikely to be so obscure as to derail students from that pathway. That leaves the orientation, culture, and practice of economics as a discipline, which has already been implicated in the persistent gender gap. Schultz and Stansbury note that:

...one informative stylized fact is the correlation across different types of diversity: among US-born PhDs, the share of first-generation college graduates is strongly correlated with both the URM [under-represented minority] share and the female share across PhD fields. This is consistent with the hypothesis that some of the same factors that limit access to economics PhDs in the United States for racial and ethnic minorities or for women also limit access to economics PhDs for those from less advantaged socioeconomic backgrounds.

That suggests to me that the socioeconomic disparity isn't necessarily a separate cause for concern for the discipline. And the work that is underway to address gender and ethnic disparities in economics may well also reduce socioeconomic disparities. How quick that change happens remains an open question.

[HT: David McKenzie at the Development Impact blog]