1. Patterns of Research Collaboration in U.S. Universities, 1981-1999 AAAS Meetings Denver, Colorado February 18, 2003 James D. Adams, University of Florida and NBER Grant C. Black, Georgia State University Roger Clemmons, University of Florida Paula E. Stephan, Georgia State University

2. Overview This is a study of collaboration in university research over the period 1981-1999. This is a study of collaboration in university research over the period 1981-1999. The topic is important for at least two reasons: (1) collaboration is a means by which knowledge spills over, and (2) collaboration is linked to the division of labor. The topic is important for at least two reasons: (1) collaboration is a means by which knowledge spills over, and (2) collaboration is linked to the division of labor. So one might think that the economic efficiency of the knowledge-creating industries is related to collaborative activities. So one might think that the economic efficiency of the knowledge-creating industries is related to collaborative activities.

3. Overview The study includes 110 leading U.S. universities and all major sciences in these universities. The study includes 110 leading U.S. universities and all major sciences in these universities. The primary data set includes 2.4 million scientific papers and 18.8 million citations to these papers. The primary data set includes 2.4 million scientific papers and 18.8 million citations to these papers. Also included is information on field and the number and location of authors. Also included is information on field and the number and location of authors. 12 fields are represented: agriculture, astronomy, biology, chemistry, computer science, economics, earth science, engineering, mathematics, medicine, physics, and psychology. 12 fields are represented: agriculture, astronomy, biology, chemistry, computer science, economics, earth science, engineering, mathematics, medicine, physics, and psychology. The data source is the Institute for Scientific Information (ISI). The data source is the Institute for Scientific Information (ISI).

4. Principal Findings on Collaboration Research output of the U.S. university system expanded by 50% over the period but grew at a faster rate in the 1980s than in the 1990s. Research output of the U.S. university system expanded by 50% over the period but grew at a faster rate in the 1980s than in the 1990s. Research collaboration grew in each of the three dimensions that we measure. Research collaboration grew in each of the three dimensions that we measure. Authors per paper increased from 2.8 to 4.2 over the period 1981-1999. Authors per paper increased from 2.8 to 4.2 over the period 1981-1999. Top 110 institutions per paper increased 1.1 to 1.2, while the share of foreign authors increased from 5% to 15% over the same time period. Top 110 institutions per paper increased 1.1 to 1.2, while the share of foreign authors increased from 5% to 15% over the same time period. Exhibits 1-3 illustrate. Exhibits 1-3 illustrate.

8. Comparative Trends in Main Forms Of Scientific Collaboration Exhibit 4 brings the three dimensions of collaboration together, normalizing each dimension on its 1981 value. Exhibit 4 brings the three dimensions of collaboration together, normalizing each dimension on its 1981 value. Team size (number of authors) is growing faster than U.S. institutional collaboration (number of top 110 schools). Team size (number of authors) is growing faster than U.S. institutional collaboration (number of top 110 schools). The share of foreign addresses is rising faster than the other two indicators. These patterns are robust across fields of science. The share of foreign addresses is rising faster than the other two indicators. These patterns are robust across fields of science. The rise in international collaboration has taken place in the recent past. The rise in international collaboration has taken place in the recent past.

10. Trends in International Collaboration by Size of Team We now explore cross-sectional patterns in the trends of the internationalization of science. We now explore cross-sectional patterns in the trends of the internationalization of science. As the measure of internationalization we again use the foreign share of addresses on scientific papers. As the measure of internationalization we again use the foreign share of addresses on scientific papers. We normalize on the 1981 value in order to compare growth patterns. We normalize on the 1981 value in order to compare growth patterns. Exhibit 5 shows that smaller teams, while less international, are becoming more international at a faster rate. Exhibit 5 shows that smaller teams, while less international, are becoming more international at a faster rate.

12. Trends in International Collaboration By Field Exhibits 6 and 7 compare the growth of internationalization by field. Exhibits 6 and 7 compare the growth of internationalization by field. The most international fields are astronomy, mathematics, and physics. The least international are agriculture, biology, and medicine. Exhibit 6 points out the differences in natural units. The most international fields are astronomy, mathematics, and physics. The least international are agriculture, biology, and medicine. Exhibit 6 points out the differences in natural units. Exhibit 7 normalizes the fields on 1981 values. This shows that the least international fields are becoming more international at a faster rate. Exhibit 7 normalizes the fields on 1981 values. This shows that the least international fields are becoming more international at a faster rate.

15. Conclusions Over time, scientific research has invited the use of larger teams. Over time, scientific research has invited the use of larger teams. In recent years research teams have become increasingly internationalized. In recent years research teams have become increasingly internationalized. There is convergence in the size distribution: team sizes that are the least international are becoming international at a faster rate. There is convergence in the size distribution: team sizes that are the least international are becoming international at a faster rate. There is convergence across scientific fields: the least international of fields are becoming more international at a faster rate. There is convergence across scientific fields: the least international of fields are becoming more international at a faster rate.

16. Conclusions Why is this happening? Why is this happening? Is it because of an increasing range of complementary skills and equipment needed to do the research, coupled with rising specialization? Is it because of an increasing range of complementary skills and equipment needed to do the research, coupled with rising specialization? Or is it due to a decline of the cost of research conducted at a distance? Or is it due to a decline of the cost of research conducted at a distance? Or to the rise of scientific research outside the U.S.? Or to the rise of scientific research outside the U.S.? Probably it is the last two explanations that are the most compelling, given the speed of the change that we observe. Probably it is the last two explanations that are the most compelling, given the speed of the change that we observe.