Everyone, it seems, loves the idea of scholars interdisciplinary work. But does academe reward those -- particular young scholars -- who actually do it?
A new study,  based on data from all people who earned Ph.D.s in 2010, suggests the opposite. In the year after earning their doctorates, those in the cohort who did interdisciplinary dissertations earned, on average, $1,700 less than those who completed dissertations in a single field. The study was conducted by Kevin M. Kniffin and Andrew S. Hanks, two postdoctoral fellows at Cornell University, and has been released by the Cornell Higher Education Research Institute.
Kniffin and Hanks used data from the Survey of Earned Doctorates, and focused on the more than 26,000 people who earned doctorates that year who are U.S. citizens. The income of new Ph.D.s, of course, varies by such factors as discipline, whether postdoctoral employment is within academe or outside it, and whether the first job after the Ph.D. is a postdoctoral fellowship. Kniffin and Hanks came up with their $1,700 gap by controlling for discipline, age, gender and ethnicity. They reasoned that because some disciplines are more likely than others to produce new doctorates who seek employment outside academe, they could address various differences in post-graduation patterns of various new doctorate holders.
The Survey of Earned Doctorates specifically asks if new Ph.D.s did a multidisciplinary dissertation, so that information was readily available for the study.
In non-academic life, Kniffin and Hanks write, there is evidence that employers reward people who can draw on varied experiences and areas of expertise. For for those who prepare for employment (in academe or in some cases out of academe) with a Ph.D., that does not appear to be the case. "The current value system in academia clearly imposes a cost on boundary spanning," they write.
Via email, Kniffin said that interdisciplinary scholars may face a range of challenges in getting the best job -- especially at the beginning of their careers. "For a department that's hiring someone whose job will be to teach Intro courses, then certainly it seems plausible that an interdisciplinary dissertation could be viewed as a liability or, at least, a distraction when people are reviewing applications for a new hire," he said.
He noted that for all the rhetoric about interdisciplinary work in academe, it may be that only senior scholars don't pay a penalty.
"Regarding career stage among academics, there's evidence that full professors -- with tenure and, perhaps almost as importantly, no need for another round of promotion applications -- tend to disproportionately pursue interdisciplinary research," Kniffin said. "Likewise, graduate students -- who might or might not have a clear sense or interest in the postgraduate labor market and who otherwise have not yet invested as much time into their academic careers -- also tend to disproportionately pursue interdisciplinary research. In contrast, there's previous work showing that assistant professors -- in the face of the up-or-out fate of tenure votes -- tend to avoid cross-disciplinary work."
Asked if the paper should discourage graduate students from pursuing interdisciplinary work, Kniffin said that was not the case. He said that there were many "good and important reasons" to do interdisciplinary work. Further, he said that the trend of "cluster hiring" at colleges and universities -- in which the emphasis is on a broad issue or problem, not a discipline -- may favor the candidacies of interdisciplinary scholars. But he said that graduate students need to understand the costs they may face for such choices.
"Until and unless that kind of pattern becomes the norm, though, graduate students should understand, at least, that there are 'extra challenges' that are entailed by conducting interdisciplinary work just as people in positions of hiring and promotion (e.g., at the department level) should be more cognizant of biases that they might hold in relation to candidates with interdisciplinary backgrounds," he said.
What of the future? In their paper, Kniffin and Hanks write that they can't be sure what to expect, but that -- from a logical perspective -- things could get better if academe evolves in rational ways (although they don't claim that rationality rules in such matters).
"[I]it is logical to expect that if academia were to become more institutionally organized to tackle contemporary problems in the way that competitive firms are expected to behave rather than remain tied to historical disciplinary boundaries, then one would expect that boundary spanners would obtain better near-term outcomes," they write.