Collaborative research is becoming the norm, and collaboration across national boundaries is generally increasing, as reflected in international coauthorship on research articles. In 1988, only 8% of the world's S&E articles had international coauthors; by 2009, this share had grown to 23%. For the world's major S&T regions, the 2009 rate ranged from about 27% to 42%.
International coauthorship trends for China, South Korea, and Taiwan differ from this pattern. Each location had reached an international coauthorship level of 20%–30% of its total articles by the early 1990s. They broadly maintained the same relative level of international collaboration, indicating that the bulk of their rapid article growth was due to articles with only domestic authors (figure
As a result of the large volume of both U.S. and EU article outputs, along with EU policies that encourage intra-Union collaboration, U.S.-based authors appeared on 43%, and EU-based authors on 67%, of the world's internationally coauthored articles in 2009. Increasingly, Asia-based authors are participating in international collaborations, signaling maturing of their scientific and engineering capabilities (figure
Size matters: China, with its rapidly growing research capacity, can support more international collaborations than Singapore. An index of international collaboration corrects for different-sized science establishments and allows comparisons of regional and country coauthorship patterns. On this index, values above "1" indicate higher-than-expected, and values below "1" lower-than-expected, degrees of collaboration with researchers in a particular country.
U.S. international collaborations measured by this index were widespread. Links were strongest with South Korea, Taiwan, Canada, and Israel; collaboration with China, Japan, and India was also above the U.S. average. The pattern of U.S. international collaborations remained mostly steady over the past decade (2000–10), though ties increased with China and weakened somewhat with a number of other Asian economies (figure
EU collaborations were equally widespread and increased measurably over the period, quite likely in response to explicit EU policies. Levels of collaboration with Asia were generally well below the expected level, and the EU collaboration index was lower (and declining) with China than with India (figure
Collaboration among Asia's growing number of researchers was generally substantially higher than expected, with high levels of collaboration between China and Japan, South Korea, Singapore, and Taiwan. Collaboration between China and India, as measured by this index, diminished noticeably over the decade amid rising Indian collaboration with South Korea and Japan (figure