FIGURE 3-2 International authorship trends.

SOURCE: National Science Board. 2004. Science and Engineering Indicators 2004 (NSB 04-1). Arlington, VA: National Science Foundation, Table 5-30. Note that internationally co-authored articles were counted more than once, for each country represented on the author list.

Union (EU) 15 countries have published more papers than the United States, and the gap in citations has been closing steadily.¹⁰ Since 1993, the EU has matched the United States in citations in the physical sciences, engineering, and mathematics but still lags in the life sciences.¹¹ The reason for this development remains unknown, but it is more likely due to an increase in the quality and quantity of research abroad than to a decrease in the quantity of US publications.

International collaboration, as assessed by the number of articles with institutional authors from more than one country, more than doubled from 1988 to 2001, leading to an increase from 8 percent to 18 percent of all S&E articles. Even though US institutions participate in most of those collaborations, the US share (but not number) of international papers has fallen since the late 1980s. Collaborative activities between other countries