Dramatic shortening of careers of scientists: The time over which half of the cohort has left the field has shortened from 35 y in the 1960s to only 5 y in the 2010s

Changing demographics of scientific careers: The rise of the temporary workforce. Staša Milojević, Filippo Radicchi, and John P. Walsh. Proceedings of the National Academy of Sciences, December 11, 2018 115 (50) 12616-12623. https://doi.org/10.1073/pnas.1800

Abstract: Contemporary science has been characterized by an exponential growth in publications and a rise of team science. At the same time, there has been an increase in the number of awarded PhD degrees, which has not been accompanied by a similar expansion in the number of academic positions. In such a competitive environment, an important measure of academic success is the ability to maintain a long active career in science. In this paper, we study workforce trends in three scientific disciplines over half a century. We find dramatic shortening of careers of scientists across all three disciplines. The time over which half of the cohort has left the field has shortened from 35 y in the 1960s to only 5 y in the 2010s. In addition, we find a rapid rise (from 25 to 60% since the 1960s) of a group of scientists who spend their entire career only as supporting authors without having led a publication. Altogether, the fraction of entering researchers who achieve full careers has diminished, while the class of temporary scientists has escalated. We provide an interpretation of our empirical results in terms of a survival model from which we infer potential factors of success in scientific career survivability. Cohort attrition can be successfully modeled by a relatively simple hazard probability function. Although we find statistically significant trends between survivability and an author’s early productivity, neither productivity nor the citation impact of early work or the level of initial collaboration can serve as a reliable predictor of ultimate survivability.

Keywords: scientific workforcescientific careerscareer success

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Discussion

Recent work on the organization of science has focused on theinternal structures of research teams and has argued that onelikely outcome of this shift in the nature of scientific work hasbeen the growth of supporting scientists, whose careers dependon being members of such teams (6, 13). Less obviously, therehas also been a concomitant increase in high-stakes evaluationand competition for funding, increasing the emphasis on pro-ductivity (43–46). One solution to this new emphasis on pro-ductivity is increasing the division of labor (47, 48). The growthof scientific team sizes is being accompanied by a transition inthe organization of scientific work from craft to bureaucraticindustrial principles, with increased division of labor and standardi-zation of tasks (13, 49, 50). The result is a growth of scientists whosefunction is to support the projects that others are leading. Ourresults confirm this scenario, showing that an increasing frac-tion of entering authors never transition from a supportingauthor to lead author role. We also show that such a trend isnot an inevitable outcome of the increasing sizes of teams, perse, but arises due to the different roles that some authors nowhave in large teams compared with the roles that members ofsmaller teams have (team members vs. collaborators). In somefields, such as ecology and robotics, lead and supporting au-thors have similar half-lives, while in others, such as astronomy,the half-lives of supporting authors is significantly shorter.Of course, there are well-known productivity advantages fromorganizing teams with a division of labor, and with having someteam members specializing in supporting roles (47). Hence, it isperhaps not surprising that science is shifting to larger teams,with more specialization, and that, increasingly, some scientistsare specializing in supporting roles. Note that we are not as-suming status or skill distinctions in our classification of leadand supporting authors (49). We are arguing that such sup-porting scientists are critical tothe production of contemporaryscience (6). However, it is also the case that institutions, such asuniversities and funding agencies, build around these traditionalstatus distinctions, for example, between postdoctoral scientists andtenure track professors (6). However, our survival analyses suggestthat the criteria predicting longevity for supporting scientists are quitedistinct from those for lead researchers and it may not be appropriateto impose similar criteria on bothgroupswhenmakingdecisionsabout who to hire or whose contract to renew. We argue there is aneed to reform career structuresin universities to account for thechanging nature of the population composition and reproductioncycles in team science, with social insect colonies rather than parent-child reproduction as a more appropriate model.While we cannot address this with our current data, we pointto a tension between the research production and teachingfunctions that academic laboratories provide (5, 12, 43, 49, 51).These two trends are bringing fundamental changes to scientificcareers, with decreasing opportunities for lead researcher po-sitions and increasing production of, and demand for, a scientificworkforce to fill positions as permanent supporting scientists.Together, these trends suggest downward pressure on careerlongevity (as more people exit the academic science labor force)and the growth of dependent supporting scientist positions tosupport the relatively shrinking share of lead researchers. How-ever, one concern is that such supporting scientist positions do notfit well with the employment system in most universities, which arestructured around a graduate apprenticeship, a short period ofpostdoctoral training, and then movement into a tenure track (andeventually tenured) professor position (5). Instead, these supportworkers may be relegated to a series of short-term postdoctoralcontracts or other forms of contingent academic work. While thetraditional model implies an up-or-out academic pipeline (withsignificant shares of the research workforce dropping out ofresearch-active academic positions at each stage), the growth ofpermanent supporting scientists may suggest an alternative careerpath that, while perhaps with shorter survival than the traditionallead researcher path, may be a growing share of the academiclabor force. Furthermore, such careers may be premised on adifferent set of criteria than is typically predictive of the careersurvival of lead researchers.Our findings show that the shift in the mode of knowledgeproduction from solo authors and small core teams (2) has co-incided with a differentiation in the scientific workforce in termsof their roles. The increased need for both the specializationand possession of specialized technical knowledge to manipulateincreasingly complex instrumentation and data has created an es-sential group of supporting contributors to knowledge. Unfortu-nately, the existing job roles and educational structures may not beresponding to these changes. Our results suggest that, while essen-tial, these supporting researchers are suffering from greater careerinstability and worse long-term career prospects in some fields.