In an era defined by global challenges that transcend borders—ranging from pandemics to climate change and the frontiers of artificial intelligence—the collaborative nature of scientific research has become ever more critical. Science, at its best, transcends nationalism, ideology, and rivalry, operating within a universal framework of curiosity, evidence, and shared pursuit of knowledge. Yet even this domain is not immune to geopolitical pressures. Recent empirical work by Robert Flynn, Britta Glennon, Raviv Murciano-Goroff, and Jiusi Xiao (2024) offers a compelling analysis of how rising tensions between the United States and China have begun to reshape the global scientific landscape.
At the heart of Flynn et al.’s inquiry is the recognition that modern science is fundamentally international in its workforce, its ideas, and its institutions. Graduate students and researchers routinely cross borders to pursue advanced training and collaboration; international co-authorship and cross-border citation networks are essential to the diffusion of knowledge. Historically, the United States has been a central hub in this ecosystem, attracting significant number of global talents, particularly from China, whose students have constituted nearly one-third of international enrollees in American STEM doctoral programs. However, beginning around 2016, this long-standing flow of individuals and ideas has faced growing disruption. Through a rigorous empirical strategy, Flynn and colleagues document how geopolitical tensions have already exerted measurable impacts across three dimensions of international science: talent mobility, knowledge diffusion, and scientist productivity.
Their approach is notable for its scale and precision. To examine changes in scientist mobility, the authors employ a dataset of millions of publicly posted academic CVs on the ORCID platform. By analyzing detailed education and employment histories, they trace the paths of doctoral students and early-career researchers in STEM fields across periods before and after the escalation of U.S.-China tensions. Ethnicity is algorithmically inferred from name-based classifiers, allowing the researchers to distinguish ethnically Chinese individuals from others, regardless of nationality—a distinction crucial to understanding the observed patterns.
The results on mobility are clear. Between 2016 and 2019, ethnically Chinese students became 15% less likely to enroll in U.S.-based STEM Ph.D. programs. Among those who did enroll, the probability of remaining in the United States after graduation declined by 4%. Notably, these individuals did not forgo international study; rather, they increasingly chose alternative destinations, primarily other English-speaking countries such as the United Kingdom, Canada, and Australia. This trend reflects a redirection of global talent flows rather than a retrenchment, suggesting a shift in the competitive landscape for attracting the world’s most promising scientists.
To validate these findings, Flynn et al. employ a difference-in-differences (DiD) framework, comparing the trajectories of ethnically Chinese students to those of non-Chinese students over time, while controlling for the field of study, prior country of education, and other relevant factors. The parallel trends assumption, critical for the validity of DiD analysis, is supported by both visual inspection and statistical tests, confirming that pre-treatment trends were similar across groups. Following the escalation of tensions, however, a distinct divergence emerges.
Beyond mobility, the study explores the diffusion of scientific knowledge by analyzing citation behavior. Drawing on comprehensive bibliometric data from Dimensions, the authors measure how frequently Chinese researchers cite U.S.-produced scientific work relative to work from the United Kingdom, which serves as a comparison group. This design accounts for general trends in citation practices, isolating the specific effects of U.S.-China tensions. The results indicate a 4–7% decline in citations from Chinese researchers to U.S. scientific work after 2016, with an even steeper decline (10–12%) for recent and frontier research, where frontier papers are defined as those within the top percentile of their field in citations.
The erosion of knowledge flows is notably asymmetric. While Chinese researchers reduced their citations of U.S. science, U.S. researchers continued to cite Chinese works at consistent rates. This asymmetry suggests selective withdrawal, rather than mutual disengagement, with Chinese scholars becoming more cautious in their engagement with U.S. research. Given the cumulative and collaborative nature of scientific progress, such disruptions weaken the connective networks that sustain global innovation.
The study’s analysis of scientific productivity further deepens these insights. Using matched samples of researchers based on observable characteristics prior to 2016, the authors compare publication outputs between ethnically Chinese and non-Chinese scientists in the United States. After 2016, they observe a 2–6% decline in productivity among Chinese-origin researchers, alongside a 7% increase in the probability of ceasing publication. These outcomes highlight that geopolitical tensions affect scientific output not only through formal barriers such as visa policies but also through broader shifts in the professional environment.
Notably, these effects appear even before the formal launch of the U.S. Department of Justice’s China Initiative in 2018, suggesting that informal pressures and evolving perceptions were already influencing scientific behavior. Survey data cited by the authors reinforce this interpretation: more than 50% of Chinese-origin scientists in the United States reported concerns about government surveillance influencing their research decisions, compared to just 12% among their non-Chinese peers.
Taken together, the evidence suggests that rising tensions are reshaping the dynamics of international science. The United States, historically a global leader in attracting and nurturing scientific talent, now faces new challenges in maintaining this position. China, while expanding its domestic research capabilities, must navigate the trade-offs of decreased international engagement. Given the scale of scientific cooperation between these two nations, shifts in their relationships carry broader implications for the global scientific community.
The authors conclude by offering optimistic caution. While measurable disruptions are evident, the underlying structures of international scientific collaboration remain resilient. There is a meaningful opportunity to rebuild trust, reinforce global partnerships, and renew the shared scientific enterprise that underpins innovation across fields.
Chaoyi Chen
References:
Flynn, Robert, Britta Glennon, Raviv Murciano-Goroff, and Jiusi Xiao (2024). Building a Wall Around Science: The Effect of U.S.-China Tensions on International Scientific Research. NBER Working Paper No. 32622. National Bureau of Economic Research.
Borítókép: pixabay.com
The post Science Under Strain appeared first on Economania blog.