Yesterday Brian Leiter posted a list of the ten most-cited law professors (actually eleven, due to a tie for tenth place) for the period from 2009 through 2013, with the promise of more statistics to come. The list consists of eleven men, of whom ten are white. With absolutely no disrespect to the outstanding scholars on the list, such a striking disparity merits some thought about its underlying causes.
One possibility is the area of specialization: clearly some specialties will be cited more than others simply because there are more people writing about them and citing one another. The most accomplished scholar of admiralty law will never receive as many citations as the most accomplished scholar of constitutional law. If men are more likely to specialize in heavily-written areas, this might provide a partial explanation. But a cursory inspection of the academy does not seem to bear this out. Many women and people of color specialize in highly-written areas such as constitutional law, criminal procedure, and so on (Heather Gerken, Pam Karlan, and Lani Guinier come immediately to my mind, and I can think of many others). That is, there must be some other explanation in addition to chosen specialty.
Some might say: “of course white men are more likely to be cited, because the most prominent scholars in highly-written subject areas are white men.” But even if we assume for the sake of argument that white men are the most prominent scholars in their subject areas, this explanation is both circular and incomplete. The “prominence” explanation is circular because the reason that white men (arguably) came to be the most prominent scholars in their fields is, at least in part, that they wrote articles that got cited a lot. And the explanation is incomplete because it simply returns us to the original question: why did these particular scholars’ articles get cited a lot in the first place?
An alternative explanation is that historically legal academia has included a disproportionately low percentage of women and people of color, and that some disparity remains today (although the disparity is considerably less than it once was, particularly among among junior faculty). Perhaps the most-cited list reflects the lingering effects of this disparity. This seems to me a plausible partial explanation. Six of the eleven scholars on the most-cited list are over sixty, meaning that a substantial portion of their careers spanned a time when women and people of color were underrepresented in law schools and the legal academy. If some of the members of the list came to prominence during this time period, those reputations may persist and influence citation counts today.
I am skeptical that this is a complete explanation for a couple of reasons. First, some of the people on the top ten list are relatively young. Second, the study covers the years 2009-2013, so the many women and people of color who entered the academy during the 1990s were well-established in their careers during that time frame. Moreover, research by Ian Ayres and Frederick Vars found that articles published in the Harvard Law Review, Stanford Law Review, and Yale Law Journal receive the most citations per year four years after publication, and that the average article has received half its lifetime citations 4.6 years after publication. This suggests that who is publishing now is more important than who was publishing in the past. A few caveats are in order: the Ayres and Vars research was published in 1999, so it’s not self-evident that everything is the same fifteen years later; likewise, their study examined all articles in the three specified journals, not merely the most cited. (A particularly interesting finding was that among all articles, those by young, female, and minority authors were actually more heavily cited after the authors corrected for time since publication, journal, and subject matter.)
Another possibility is that articles are more likely to be cited if they appear in the most prominent journals, and those journals publish more articles by men. Some empirical research supports this hypothesis. In 2009, for example, Minna Kotkin documented a disparity in the percentage of women and men who publish in the “top fifteen” journals: 20.4% of the articles published over a three-year period were authored by women, while during the same three-year period women comprised 31% of the professors in the academy. Kotkin found that the disparity was not fully explained by “quantifiable factors” such as number of years in the academy and subject matter. Perhaps to some degree student editors are influenced by prospective authors’ letterhead, which might result in a gender disparity in the most prominent journals because the gender disparity at high-ranked schools is greater than in the academy as a whole. Or editors might be influenced by authors’ publishing track records, which might also result in a disparity because it would mean that because more men publish articles in prominent journals, then more men will publish articles in prominent journals. This latter possibility shows the way that gender disparities might (or perhaps already have?) become self-reinforcing over time.
It’s also worth considering whether certain groups within academia are more likely to cite to other members of those groups, establishing self-reinforcing patterns of citation. This possibility calls to mind Richard Delgado’s work, published thirty years ago, titled The Imperial Scholar: Reflections on a Review of Civil Rights Literature. Delgado observed that at the time there were about one hundred non-white members of the legal academy, many of whom were and are quite well known. Yet nearly all the “leading articles” on civil rights were by white authors, and that while those authors were almost always highly sympathetic to “minority rights,” they rarely cited non-white authors. He observed: “legal scholars whose work really counts almost never [cite to non-white authors]. The important work is published in eight or ten law reviews and is written by a small group of professors, who teach in the major law schools.” He describes it thus:
“Paul Brest cites Laurence Tribe. Laurence Tribe cites Paul Brest and Owen Fiss. Owen Fiss cites Bruce Ackerman, who cites Paul Brest and Frank Michelman, who cites Owen Fiss and Laurence Tribe and Kenneth Karst . . . It does not matter where one enters this universe; one comes to the same result: an inner circle of about a dozen white, male writers who comment on, take polite issue with, extol, criticize, and expand on each other’s ideas.”
I do not know whether such a citation pattern continues to take place today, thirty years later, among the most highly cited legal academics (both those in the top ten and those ranked slightly below). I am not claiming that anyone on the list has engaged in such a pattern, certainly not intentionally. But I think it is possible that a citation pattern such as the one Delgado describes exists today; that research might profitably examine whether this is so; and that if such a pattern exists, perhaps scholars who find themselves falling into such a pattern would find their research enriched by considering the many scholarly contributions of women and people of color.
A final possibility, which is pure speculation on my part, so I present it only in that light, is that perhaps men are more likely to cite themselves than are women. If highly-cited authors publish a lot and cite to a lot of their own articles, perhaps this exerts some influence on citation counts.
This brief blog post is by no means intended as an exhaustive catalog of explanations; I am sure there are many that I have not thought of or discussed. I suspect that, as with most disparities, the explanations are multiple and complex. Regardless of the explanation, however, I think it’s important to think about why the disparity is happening rather than to shrug our shoulders and assume that it’s just the way things are.
And — for my fellow academics — it’s important to think not only about possible explanations, but also about constructive measures we can take to correct them. As just one example, some of the discussion above calls to mind the gender disparity in student note publication, which I examined in a preliminary fashion here and catalogued more exhaustively, with my coauthor Jen Mullins, in a subsequent article available here. Professors should bear lingering disparities such as these in mind as they conduct their own research and advise promising students who hope to enter academia.