The paper confirms the intuition that there are self-reproducing departmental status systems within disciplines. Job candidates in all disciplines are exchanged in a well-defined manner between three classes of departments. Class I departments, at the top, exchange students amongst themselves and supply lower-tier departments with students but do not hire from them. Class II departments are on the “semi-periphery,” generally exchanging candidates with each other (though there is a hierarchical element to this) and also sending students to Class III departments, which never place students outside of their class and usually do not hire students from within their class.

This broad structure applies to all disciplines, though some draw sharper boundaries than others between Classes I and II. (In Sociology, for instance, the differentiation is particularly strong.) Within Class I departments, there’s a good deal of variation across disciplines in the degree of factionalization within the elite departments and the solidarity of the exchange system, as measured by within-class exchanges of students. Economics has the most cohesive elite faction and its “dominance over the entire discipline is overwhelming.” Class I Psychology departments, by contrast, are considerably more decentralized, with three contending factions. Different measures bring out different aspects of the structure. Economics scores highest on all exchange-based measures of hierarchy and solidarity.

There’s an old article by Arthur Stinchcombe called “A Structural Analysis of Sociology” which, only half-jokingly, treats the exchange of job candidates in sociology from the perspective of Levi-Strauss’s structural anthropology: departments are tribes, graduate students are women to be married off, and areas of specialization are clan-markers that help define which exchanges are appropriate and which are taboo. Han’s paper does a nice job of quantifying the structure of exchange in graduate students and demonstrating how it varies across disciplines. It wouldn’t do prospective graduate students any harm to have a clear picture of this social structure in mind—together with a grasp of their own potential place in it as a unit of exchange—before applying to grad school.