Guest blogger: Explaining postdoc internationalization at US universities

Dr. Brendan Cantwell (Michigan State University)

Dr. Brendan Cantwell
(Michigan State University)

This guest entry is written by Dr. Brendan Cantwell who is currently employed as an assistant professor at the Department of Educational Administration at Michigan State University. His current research interests include higher education organization, governance and policy, with focus on comparative education, political economy and theory. 

Since the 1990s over 50% of all postdoctoral researchers (‘postdocs’) working at universities in the United States (US) have been temporary visa holders, or ‘international’. This makes postdocs the most internationalized group at American universities.

The fact that over 50% of postdocs are international is especially striking when compared to student enrollments; international students accounted for only 3.7% of total enrollments in the US during the 2011/2012 academic year. Why, then, do most postdocs come from abroad?

Over parts of the past five years I have studied the employment of international postdocs, primarily in the US but also in the United Kingdom. One of my objectives was to understand why so many researchers work as postdocs abroad. I began this research qualitatively by interviewing international postdocs and their supervisors. I examined the experiences of international postdocs, the role international postdocs play in the production of knowledge, and the process by which postdocs become employed internationally.  From these studies I drew two main conclusions.

first graph

First, international postdoc mobility requires demand for postdocs from aboard, as well as the supply of internationally mobile researchers. Global expansion of higher education, and especially rapid growth of higher education systems in Asia, produced a large supply of PhD researchers looking for jobs abroad. But professors also had to be willing to hire international postdocs. In other words, postdoc mobility would be impossible if there were not individual professors and universities interested in hiring international postdocs.

I found that in many cases professors were eager to hire international postdocs. Because the supply of PhD researchers globally is large, professors in well-resourced systems were able to attract highly talented researchers to their groups. Moreover, some professors appeared to prefer international postdocs because of a perception that international researchers worked harder than did domestic researchers.

A second main conclusion from my qualitative research was that postdoc mobility was determined complexly through the interaction of local, national, and global factors. As such, considering independent ‘push’ and ‘pull’ factors was probably not sufficient. Push-pull accounts essentially claim that academics flow from low resource countries to high resource countries. While this is empirically correct, at least in the majority of cases, it could not explain increased mobility of particular groups to particular locations at particular times. To be direct, push-pull accounts could not fully explain why international postdoc employment had recently increased at US universities.

Beginning with the assumptions that (1) there was a demand for international postdocs at US universities and (2) international mobility was determined complexly by local, national, and global factors, with Barrett J. Taylor I modeled international postdoc employment at US universities. Our study used panel regression analysis with data from the US National Science Foundation from 1989 to 2009. We focused on ‘demand’ by considering variables that may have predicted international postdoc employment.

Following the assumption that demand for postdocs was shaped by local, national, and global factors, we included variables at each of these ‘levels’. For example, we assumed that local conditions such as the size of a university’s postgraduate research enterprise and the extent to which a university is already internationalized may have predicted international postdoc employment. In the US most postdocs are hired using funds awarded through external research grants. Therefore we posited that the share of nationally sourced research funds might have predicted postdoc employment. Global factors are difficult to model. Globalization is a complex processes that includes both objective and subjective elements. Based on the presumption that all aspects globalization had increased over time we included a time trend in our model as a proxy for global factors.

Our analysis identified two main variables that predicted international postdoc employment at US universities. The first major finding was that research and development (R&D) expenditures funded by the US federal government predicted international postdoc employment. The US government had increased the amount of money it spent on academic research and individual universities used some of those funds to employ postdocs from abroad. The relationship between federal research funding and postdoc employment remained positive and significant even after controlling for the employment of US postdocs. This suggested that US universities used federal R&D funds disproportionally to employ postdocs who were ‘international’. In other words, US government research policy appeared, in part, to have stimulated demand for international postdocs.

The second major finding was that over time US universities employed more international postdocs even when all other variables were held constant. The figure below shows the estimated increased demand for international postdocs at US universities when all other variables were held at their means. We hypothesized that the increased tendency over time to hire international postdocs was attributable to global factors.

second graph

Our finding that the passage of time predicted demand for international postdocs is particularly interesting because there were no clearly correct interpretations of the finding. Assuming that the time effect was attributable to globalization we still do not know what aspects of globalization contributed to the internationalization of postdoc labor. One plausible explanation was that global expansion of higher education lead to more and more international postdocs being hired at US universities. In other words there were likely more qualified candidates from around the world competing for a growing number of postdoc positions. But the increased tendency to employ more international postdocs may also have been related to subjective aspects of globalization. The professors who hired postdocs may have been aware that because of globalization processes their research groups competed on an international basis. Because these professors believed globalization increased cross-border competition they may have actively sought to build international research groups.

What does this mean for future research? I argue that the best way to answer questions like why there are so many international postdocs at US universities is to critically examine the way local, national, and global factors interact. In doing so, however, I believe it is important to attend not only to the objective elements of globalization but also to subjective elements. It is likely that no single answer can satisfy our questions but that conducting research using a variety of methods can help to develop a more satisfying set of possible explanations.


  • Cantwell, B. (2011). Academic in-sourcing: international postdoctoral employment and new modes of academic production. Journal of Higher Education Policy and Management, 33(2), 101-114.
  • Cantwell, B. (2011). Transnational mobility and international academic employment: Gatekeeping in an academic competition arena. Minerva, 49(4), 425-445.
  • Cantwell, B., & Lee, J. J. (2010). Unseen Workers in the Academic Factory: Perceptions of Neoracism Among International Postdocs in the United States and the United Kingdom. Harvard Educational Review, 80(4), 490-517.
  • Cantwell, B., & Taylor, B. J. (2013). Internationalization of the postdoctorate in the United States: analyzing the demand for international postdoc labor. Higher Education, [online first].
  • Institute of International Education. (2012). Open doors 2012. New York: IIE.
  • Marginson, S., & Rhoades, G. (2002). Beyond national states, markets, and systems of higher education: A glonacal agency heuristic. Higher Education, 43(3), 281-309.
  • National Science Foundation. (2011). Survey of graduate students and postdoctorates in science and engineering. Arlington, VA, USA: NSF.