Academic mobility constitutes a major lever for the professional development of scientists: it enhances productivity (Dubois, Rochet, & Schlenker, 2014), increases the impact of publications (Wagner & Jonkers, 2017), and contributes to the acquisition of new skills in research and teaching (Groves, López, & Carvalho, 2018). However, despite strong incentives from universities and funding agencies, mobility continues to be constrained by a range of factors, demographic (e.g., parental status) and professional (e.g., access to funding), which limit opportunities for certain researchers.
This analysis, which includes responses from nearly 3,000 PhD holders from the Wallonia-Brussels Federation (WBF), explores their mobility trajectories. The aim is to understand the factors that influence mobility during and after the doctorate, the reasons behind these movements, as well as the prospects of returning to Belgium.
Who are the researchers surveyed?
The data come from the "Future of PhD Holders" survey, conducted by the Observatory. This is a longitudinal study examining the career trajectories of PhD holders, incorporating new cohorts of graduates from universities in the Wallonia-Brussels Federation (WBF) every three years. The first data collection, carried out in 2019, focused on PhD holders who defended their thesis between January 2012 and May 2018. Details regarding the sample characteristics and methodology are available in the first report published from this survey (Bebiroglu et al., 2019). The second round of data collection, conducted in 2022, focused on PhD holders who defended their thesis between June 2018 and May 2021.
In total, 2,912 PhD holders (43.9% women) participated in the survey. Their average age was 35.2 years (SD = 6.2), and they had obtained their doctorate on average 2.9 years prior to the survey (SD = 2.9). The largest group of respondents (45.1%, n = 1,313) held a PhD in the Exact and Natural Sciences (ENS), followed by 31.1% (n = 906) in the Humanities and Social Sciences (HSS), and 23.8% (n = 693) in Life and Health Sciences.
Our respondents represented 96 nationalities, although the majority (63.3%, n = 1,824) were Belgian nationals.
Among the 2,600 individuals who provided information on their country of work and nationality, 1,676 were Belgian nationals, 404 were citizens of another European Union (EU) country, and 520 were nationals of countries outside the EU.
Of the 1,596 doctorate holders reporting that they were professionally active in Belgium, 1,339 (83.9%) were Belgian nationals, 154 (9.6%) were EU citizens—representing 38.1% of all EU graduates—and 103 (6.5%) were non-EU nationals, representing 19.8% of all non-EU graduates.
When Belgian doctorate holders settle abroad (n = 339), they tend to favor France (n = 56; 16.5%), the United States (n = 53; 15.6%), the United Kingdom (n = 41; 12.1%), and Germany (n = 31; 9.1%). As these percentages indicate, the geographical distribution of Belgian doctorate holders abroad remains fragmented, with no single country concentrating the majority of observed mobility.
The diagram below illustrates the pathways of PhD holders, from their nationality to their country of employment. This allows us to trace their movements throughout their educational and professional journeys. Flows with greater width represent a higher number of individuals. For clarity, only countries with a minimum of five PhD holders have been included.
Let’s take the example of Italy, shown in orange below: among the 89 PhD holders of Italian nationality, 72 completed a master’s degree in Italy, while 17 did so in Belgium. After completing their doctorate in Belgium, 33 remained in the country to work, 25 returned to Italy, 8 moved to France, 7 to the United Kingdom, and 5 to the United States. The remaining 8 (not included in the diagram) chose other destinations, such as Norway (1 person) or Spain (1 person).
The diagram below illustrates the mobility trajectories of PhD holders, from their nationality to their country of employment. Returning to the example of Italy, among Italian PhD holders who obtained their degree in Belgium, 33 remained in Belgium, 25 returned to Italy, 8 moved to France, 7 to the United Kingdom, and 5 to the United States.
From this diagram, we observe the following trends:
PhD holders of Belgian nationality predominantly remain in Belgium.
Many foreign PhD holders return to work in their country of origin, particularly those from African nations such as the Democratic Republic of Congo, Benin, and Cameroon, as well as from Asian countries, notably China and Vietnam.
Among our sample, 1,032 PhD holders reported working outside of Belgium. The main reasons for leaving the country after the doctorate vary by nationality:
For PhD holders of Belgian nationality (n = 339), the motivations are primarily professional. These include the need for mobility, often expected in order to advance their careers (n = 156), and the lack of satisfactory job opportunities in Belgium (n = 138).
For those who do not hold Belgian nationality (n = 693), the most frequently cited reasons are the obligation to return to their home country after completing their doctorate (n = 278), as well as family-related considerations (n = 245).
Among PhD holders working abroad who answered this question (n = 1,022), nearly half (n = 502) expressed an intention to return to work in Belgium. This proportion was higher among Belgian nationals, with 61.2% (n = 205) indicating a desire to return, compared to 43.2% (n = 297) among non-Belgian nationals.
Among 2,790 PhD holders who answered the mobility question, 12.7% (n = 354) were mobile only during their doctorate, 21.1% (n = 589) were mobile only after their doctorate, and 19.8% (n = 553) were mobile both during and after their doctorate. In contrast, 46.4% (n = 1,294) had never been in a mobility situation.
Year of PhD completion: The figure below illustrates the variations in mobility percentages during and after the doctorate for cohorts graduating between 2012 and 2021. For these cohorts, mobility during PhD fluctuated between 26.2% and 37.1%, showing relatively limited variation over the years. Between 2012 and 2018, for each graduating cohort, mobility after the doctorate was consistently higher than mobility during the doctorate. However, starting in 2018, a decline in post-doctoral mobility is observed. This trend can likely be attributed to the COVID-19 restrictions that began in early 2020, which significantly impacted international travel for approximately two years.
Field of research: Mobility rates vary depending on the field of research.
PhD holders in Life and Health Sciences have the lowest mobility rates, both during their doctorate (22.4%) and after (35.2%).
In comparison, PhD holders in Humanities and Social Sciences exhibit higher mobility rates (42.4% during and 40.5% after), as do those in Exact and Natural Sciences (31.0% during and 44.2% after).
Nationality: Mobility rates vary depending on nationality. PhD holders with Belgian nationality have lower mobility rates, both during their doctorate (27.6%) and after (34.5%), compared to those with other nationalities.
Gender: Few differences are observed between men and women regarding mobility during the doctorate. However, the differences become more pronounced after the doctorate: 45.7% of men were in mobility, compared to 35.1% of women.
Having children before the doctorate: In our sample, 12% (n = 348) of PhD holders reported having one or more children before their doctorate. The mobility rates of PhD holders show little variation between those who had children before their doctorate and those without children.
Having children during the doctorate: In our sample, 22.8% (n = 664) had one or more children during their doctorate. A decrease in mobility is observed among parents who had children during their doctorate. The presence of young children appears to play a significant role in these dynamics. This highlights that the issue is not solely about having children, but more importantly about the timing of parenthood in their professional journey. Thus, the timing of parenthood emerges as an important factor influencing the mobility of PhD holders.
Are mothers more affected than fathers?
Yes and no.
On one hand, the results suggest that parenthood has a more negative impact on the post-PhD mobility of mothers than fathers, especially for those who had children during their PhD. This highlights a greater incompatibility between post-PhD mobility and being a mother during the doctoral period.
On the other hand, the results show that parenthood during the PhD is a hindrance to mobility during the PhD, regardless of gender.
It is important to note that the direction of the effect is not tested. It is possible that mothers who had children during or after their PhD did not have the opportunity to benefit from mobility, or conversely, that those who did not prioritize mobility were more inclined to have children.
In 2021, we surveyed PhD holders who had never taken part in a mobility experience to find out whether they would have liked to do so.
Among those who had not engaged in mobility during their PhD, 53.7% (n = 289) expressed a wish that they had.
Among those who had not participated in mobility after their PhD, 40.7% (n = 259) indicated that they would have liked to.
These results show that an important proportion of respondents regret not having had the opportunity to take part in mobility experiences.
Why was this wish not fulfilled?
A question was posed to PhD holders who had not undertaken any mobility but who, in retrospect, expressed a desire to have done so: what were the reasons that prevented them from fulfilling this wish?
Among the reasons mentioned, financial difficulties topped the list: 118 respondents who had expressed a wish to engage in mobility cited financial reasons as the main explanation for their lack of mobility.
Next, 112 PhD holders selected “other reasons” and provided written explanations. Three additional factors were frequently mentioned in their responses. The most common among them was the “workload and time constraints,” particularly in relation to assistantship and teaching positions (n = 20).
« The workload from assistantship duties (TP) and mentoring (graduate students) was too heavy to allow time for extended stays abroad.»
Some individuals highlighted the difficulty of reconciling mobility with the expectations of their supervisors:
« As I was working as his assistant, my supervisor only allowed me to go abroad during
my vacation month. »
In second place, we find "the impact of the COVID-19 pandemic", mentioned by 15 individuals, primarily due to travel restrictions.
« Border closures due to COVID. »
Finally, the "constraints imposed by supervisors" are also a barrier, cited by 14 individuals:
« My supervisor refused to support/approve my application. »
« My supervisor advised against it. »
The third most frequently selected item concerns family reasons. These results show that, for some individuals, the lack of mobility is not due to a lack of interest, but to financial, professional, or personal constraints that are difficult to overcome.
In the visualization below, each point represents an individual and can be grouped or colored based on their responses. With the parameter panel, you can easily interact with the data — apply filters, select specific survey questions, and switch between different views.
These results, based on the responses of nearly 3,000 PhD holders from the Wallonia-Brussels Federation (FWB), demonstrate that PhD mobility is influenced by a combination of academic, professional, and personal factors. While some Belgian PhD holders choose to go abroad to improve their career prospects, many also express a desire to return. For international PhD holders, mobility is often driven by obligations to work in their home country after their thesis or by family reasons, leading them to return to their country of origin.
The year of graduation, nationality, and research field influence mobility rates. Mobility inequalities are also marked by gender and parenthood, with mothers being particularly limited in their ability to move after their PhD. Additionally, many PhD holders regret not having had the opportunity to go abroad, citing major obstacles such as financial constraints, heavy workloads, or family reasons.
This study highlights the need for mobility support policies, particularly by easing financial and institutional constraints, to provide PhD holders with more balanced and tailored mobility opportunities that meet their specific needs.
Author
Neda Bebiroglu, Scientific advisor and coordinator, Observatory of Research and Scientific Careers
Contact
🌐https://observatoire.frs-fnrs.be
🖇️https://www.linkedin.com/company/observatoire-frs-fnrs