A pair of studies were recently released that analyzed national Survey of Earned Doctorates data to discern employment patterns of PhDs with interdisciplinary dissertation topics. The survey form now allows students to identify a primary and secondary field, (“If your dissertation was interdisciplinary, list the name and number of your secondary field”) which researchers have been using as a proxy for interdisciplinary research.
The Cornell study (Kniffin & Hanks) looked at PhDs graduating in 2010. The report, which has not been peer reviewed or published in a archival source as of yet, has gotten picked up by a variety of blogs and email listservs because of potentially dramatic and negative findings. The headline that “interdisciplinary PhDs earn less” is prompted by an average $1,700 annual salary difference between the two groups– a small difference in relation to the $5000 ranges used to bin and collect the salary data. More curiously, they found that students whose fathers had earned a college degree were slightly more likely to name a secondary field, and that non-citizens were more likely than U.S. citizens to pursue interdisciplinary research (4.7% higher probability). (Can you tell I am skeptical of this study?)
Millar’s findings were peer reviewed, much more promising, and thus less likely to be featured on blog sites. She compared two sets of PhD graduates: from 2004-2007 and 2008. She found that interdisciplinary PhDs were more likely than disciplinary PhDs to find employment in academia (the odds are 26% higher), and that the type of dissertation has no statistically significant effect on the type of position (post-doc, tenure-track, etc.). Related to this, students with interdisciplinary dissertations have more publications. This can be partly explained by the type of employment because publications are more highly valued in academia, so graduates working in academia and those pursing an academic career path would tend to focus on those.
Finally, an evaluation of NSF’s IGERT program compared a set of IGERT graduates to a comparison group of graduates without formal interdisciplinary training. The study found that IGERT students graduated in less time on average (5.63 vs. 6.04 years), considered fewer different employment sectors on average (2.39 vs. 2.10), were more positive in self-reports of how well their training prepared them for faculty positions, and self-reported less difficulty in finding postgraduate employment.
So what’s the answer? Is it worth doing an interdisciplinary PhD? Are you taking a big career risk?