The emergence of China as a research powerhouse has been one of the big themes for global science in the past four decades. Now, a study by researchers in China, the United States, and two European countries suggests that expatriate Chinese scientists working in the U.S. and Europe are increasingly returning to their homeland—a development with potentially important implications for China’s future science and research profile (Sci. Publ. Policy, doi: 10.1093/scipol/scz056).

Overseas connections

Since the end of the Cultural Revolution in 1976, China’s science-and-technology capabilities have experienced what the authors of the new study describe as an “exponential rise.” R&D spending in 2017 in the country reportedly amounted to RMB1.75 trillion (US$259 billion), or 2.12% of China’s rapidly expanding GDP. While that’s less than the 2.74% of GDP spent on R&D in the United States, it’s a larger percentage than the EU’s R&D share of 2.06%.

Much of China’s gain in scientific performance traces to the emergence of a large and improving scientific talent pool—which, in turn, has been tied partly to the large number of native scientists who have traveled to the United States, Europe and other areas to receive education and training. These programs are believed to have benefited China’s research performance both by virtue of the training itself, and by plugging Chinese scientists into foreign-based collaboration and publishing networks.

Since the mid-1990s, China has undertaken a series of programs to attract such expatriate scientists back to their homeland—part of a larger effort to consolidate and expand the country’s scientific leadership. But reliable statistics have been scarce, and it’s been difficult to suss out the actual impact of these programs and to quantify the impact of “mobile” researchers on Chinese science as a whole.

Bibliometric approach

To overcome some of these problems and help fill in the picture, the researchers behind the new study mined the Scopus database of the scientific-publishing conglomerate Elsevier for information on authors’ addresses over the course of their scientific careers. This allowed the team, according to the study, to “trace Chinese researchers who first published in China and subsequently published in a different country,” and to use those data as a proxy for researcher mobility.

In one result, the analysis suggested that expatriate Chinese researchers are returning to China, both from the United States and Europe, at an increasing rate. The researchers found that, as measured by their method, 4,569 Chinese scientists that had been working in the United States returned to China in 2017—69% more than the 2,703 who returned in 2010. The number who returned home from Europe, meanwhile, more than doubled, from 1,141 in 2010 to 2,371 in 2017.

High-impact returnees

The researchers also found that the impact of research published by Chinese scientists returning from foreign residence, as measured by citations, was greater than that of Chinese scientists who hadn’t left their homeland. The authors of the study tied that observation to the greater tendency of Chinese scientists who had spent time abroad both to participate in internationally coauthored collaborations and, more generally, to benefit from the “scientific social capital” built up by forging strong ties with foreign scientific systems.

One of the study’s authors, Caroline Wagner of Ohio State University, USA, noted that Chinese leaders “value the connections” with other countries as “a way to create linkages with the worldwide scientific community”—even for expatriate Chinese scientists who don’t return to the homeland. Increasingly, the new work suggests, the tendency of such scientists to return to China could bring those linkages back home, further boosting the integration of domestic Chinese science into the worldwide system.

In addition to Wagner, the authors on the study included Cong Cao of the University of Nottingham Ningbo China; Jeroen Baas of Elsevier, Netherlands; and Koen Jonkers of the European Commission, Belgium.