SCIENCE & ENGINEERING INDICATORS

The percentage of worldwide S&E articles produced with international collaboration—that is, by authors from universities and research institutions in at least two countries—rose from 17% to 23% between 2008 and 2018^{​The worldwide international collaboration rates should not be used as benchmarks against which to compare the share of international co-publications of individual countries. Due to the multi-lateral nature of co-publications, the world's share based on full counting of co-publications and publications is not directly comparable to the country scores. Individual country scores also use whole counting where each country, with an institutional address on the paper, receives one point. Therefore the basis count for individual countries will be larger than the number of papers that have authors with institutional addresses from 2 or more countries, which is the basis for the worldwide collaboration computation.} (Table S5a-32). International connections among researchers indicate the expanding research capabilities around the world. Researchers collaborate for a number of reasons including access to a desirable collaborator; access to costly or shared equipment; or conditions attached to research funding that require international collaboration (Wagner 2018). S&E research has steadily become more global over the past decade, which can be measured by examining coauthorships on peer-reviewed articles (Glänzel and Schubert 2005; Royal Society 2011). International collaborations have been shown to increase the impact of research, as measured by citations (Sugimoto et al. 2017). Domestic collaboration, between academic, government, and industry, also receive higher citation rates (see forthcoming Indicators 2020 report “Invention, Knowledge Transfer, and Innovation,” section Business Collaboration in Peer-Reviewed Publications).

Among the 15 largest producers of S&E scholarly articles in 2018, most have high rates of international collaboration: the UK (62%), Australia (60%), France (59%), Canada (56%), Germany (53%), Spain (53%), and Italy (50%) (Figure 5a-7).^{​Figure 5a-7 uses whole counting: each collaborating country or economy is credited with one count. The United States has a larger number of articles on a whole-count basis because the United States is more collaborative than China. Accurate cross-country comparisons for article production uses fractional counting as shown in Figure 5a-3.} The United States has a collaboration rate of 39%, slightly below the average collaboration rate for the largest 15 producers (41%).^{​The United States serves in a leadership position in international collaboration as determined by the number of times that an author from a U.S. institution is listed first among an article’s authors. See Chinchilla-Rodríguez Z, Sugimoto CR, Larivière V. 2019. Follow the Leader: On the Relationship between Leadership and Scholarly Impact in International Collaborations. PLOS ONE 14(6):e0218309. Available at https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0218309 Accessed 18 September 2019.}

Beyond the 15 largest producers, in 2018 collaboration rates vary widely: Saudi Arabia (75%), Switzerland (72%), and Belgium (71%) have relatively high collaboration rates whereas those with relatively low rates include India (18%), China (22%), and Russia (23%) (Table S5a-32). U.S. authors collaborated with at least one international peer on 39% of articles in 2018 compared to 27% in 2008 (Table S5a-32). Countries in the EU show high collaboration rates by virtue of their size, geographic proximity, and political support for cross-country collaboration (Wagner 2018). Germany, France, and the UK collaborate on over half of their articles; collaborations for these three countries increased from around 40% of their publications involving international collaboration in 2008 to over 50% in 2018 (Figure 5a-7 and Table S5a-32).

In 2018, U.S. authors collaborated most frequently with authors from China. In 1996, the United States’ largest collaboration country was the United Kingdom (13%) (Table S5a-33). In comparison, researchers in China collaborated on about 26% of U.S. internationally coauthored articles in 2018 (Table 5a-2). China’s rapidly growing scientific and technological capabilities, such as rising R&D spending and university degree awards, likely contributed to this high rate of collaboration. Another possible factor may be the educational ties between the two countries: China is the largest foreign country of origin for international U.S. S&E doctorate recipients (Figure 2-17). U.S. authors also had substantial collaboration with authors from the UK (13%), Germany (11%), and Canada (10%) (Table 5a-2). Authors from China (44%), South Korea (44%), and Canada (43%) have notably high collaboration rates with U.S. authors as indicated by the share of these countries’ international articles with a U.S. author (Table 5a-2).

International collaboration can also be compared using an index. This provides another method for comparing across countries and time, while reducing the effects of country size (He 2009). The index is obtained by dividing a country’s share of collaboration with another country by its overall share of international collaborations with all countries. The index measures the relative strength of collaborative ties between two countries. An index of 1.0 occurs when coauthorship between two countries is exactly proportional to their overall shares of international collaborations. Index values above 1.0 indicate stronger ties, while scores below 1.0 indicate weaker collaborative ties. The index of internationally coauthored S&E publications increased between the United States and most other major research countries from 1996 to 2018,^{​The difference between 2018 and 1996 index values are rounded to show trends; some index values are slightly negative due to year-to-year fluctuations. A 22-year time span is used because international collaboration is a slow-moving trend.} with the exceptions of South Korea (1.4 to 1.2), Japan (1.0 to 0.9), and India (0.9 to 0.8) (Figure 5a-8). The international collaboration index can also be used to understand the strength of partnerships between countries and regions (NSB Indicators 2018: Coauthorship and Collaboration in S&E Literature).