International mobility has long been accepted among academic researchers and it is quite normal for a research laboratory to have at least half a dozen nationalities among its members. There are many perceived advantages to this international exchange of academic talent and on an individual level, it is seen as the established route to an independent research career. Among the top choices for international postdoctoral training is the USA. In other words, the urban legend among researchers is that to have one´s own independent research laboratory, one must do a postdoc, and preferably in the USA. Ironically, despite being scientists and supposedly rational, all too often in academia we tend to rely on word-of-mouth information and forget to ask for some real-world data.
To address this, I took the liberty to collect some real-world evidence of researchers who have recently established their independent laboratories. Before going into the in-depth methodology of this purely observational study, there are some caveats that I must declare. First of all, there is a wide interpretation of success and I of all people, am not endorsing independent research careers as the only way to a fulfilling career; however, given that some 86% of researchers who pursue postdoctoral training have the intention of pursuing an academic research career as an independent principal investigator (Hayter and Parker, 2019), I believe it would be fair to look at what type of training can help researchers reach this goal.
Having the recognition from an institution to embark on an independent research career is one thing, but what is even more important, is the ability to lead research projects to fruition and publish in scientific journals that are well recognized by peers in the relevant scientific community. Here again, we come to the point of defining success and while the impact factor is contentious, as immunologists, we would all be very proud of having our papers being published in journals such as Nature Immunology, Science Immunology and Immunity.
This observational study was therefore conducted as follows:
Hypotheses/Questions
- Is international experience necessary for a successful research career?
- Is the USA the best place for postdoctoral training?
Methodology
- One hundred of the most recently published papers from each of the top three immunology journals Nature Immunology, Science Immunology and Immunity were included in the study.
- Corresponding authors from each of these papers were examined based on their publicly available information (from e.g. institutional websites and social media profiles).
- “New independent investigators” were defined as those who have started their own laboratory in the past 10 years.
- The new investigators´ PhD and postdoctoral institutions and their locations were examined and compared to their current institution.
- Researchers whose information are not publicly available were excluded from the study.
Results
Of the 300 papers analyzed, some 56 papers had new independent investigators as one of the corresponding authors, i.e. less than 20%. Without further context, it is difficult to comment on what exactly this number may suggest.
Of the new independent investigators in the 56 papers, 32 or 57% of them have international research experience, i.e. they relocated to another country at some point during their training (from PhD to postdoc or from postdoc to their current position) (Figure 1). While 57% is more than half, the proportion of successful new independent researchers with international experience seemed to be relatively low, given the much-touted benefits of international mobility.
Given that the USA is arguably still the top country when it comes to research output in the world, it may be that those who have trained in the USA during their PhD, no longer gain advantage by going abroad but rather gain by going to another prestigious institution in the USA. To look into this, the data was further subdivided based on where the researchers completed their doctoral training (USA versus international). Among of this subset of 36 researchers who completed their doctorates outside of the USA, the proportion with international experience increased substantially and 78% have research experience abroad (Figure 2).
Conversely, among the 20 researchers who completed their doctorates in the USA, only 20% went on to conduct research abroad while most continued their research at another institution in the USA (65%) (Figure 3).
Clearly, when it comes to international mobility, it seems to benefit non-US researchers more than researchers who are already in the USA.
To address the second question of “is the USA still the best place for postdoctoral training”, the answer is a resounding yes. Of the 56 new independent researchers who recently published in the top immunology journals, 37 did their postdoc in the USA (66%), followed by Germany, Switzerland, UK and Australia (Table 1).
| Postdoctoral Training Location | Number of Researchers |
| USA | 37 |
| Germany | 4 |
| Switzerland | 3 |
| UK | 3 |
| Australia | 2 |
Interpretation and observations
Before dissecting a small dataset even further and making any inappropriate conclusions, I must emphasize again that this is an observational study and the trends observed may or may not apply with a larger dataset and in different subject areas. Nevertheless, the trend supports the generally accepted wisdom of the USA being the best place for postdoctoral training. However, what is far more surprising, may be the 9% of successful new independent researchers who have never left their original institutions. My interpretation from this is that, while there may be a template to success, it may be even more important to follow your research interests, and even if that means staying in the same institution. Of course, this is only one interpretation and there may be other reasons that are not immediately transparent from the numbers.
One particularly outstanding data point is that of The University of Oklahoma – from a rankings point of view, it is not among the top universities in the world. Yet, among the researchers who have recently successfully established themselves as top immunologists in the world, two of them completed their doctoral training at The University of Oklahoma (for reference, three of the group of 56 were trained at Harvard). Does this mean that it is about time that we focused less on the signals of success and instead, pay attention to the actual scientific discoveries? And perhaps, instead of following templates to success, it is time to carve out your own niche and be no one else but your most authentic self.
One thing that is likely to help along this journey to independence is having your own research funding, which enables you to work on a subject of your interest in a laboratory of your choosing – such opportunities are more common than you might think – one resource for such funding opportunities is the curated list on GRANTguide for postdoctoral opportunities, and don´t forget to check out the resources that your own university´s research office provides.
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