Roger M. Clemmons
Department of Small Animal Clinical Sciences
College of Veterinary Medicine
University of Florida
P.O. Box 100126
Gainsville, FL 32610-0126
NBER Working Papers and Publications
|January 2006||How Rapidly Does Science Leak Out?|
with James D. Adams, Paula E. Stephan: w11997
In science as well as technology, the diffusion of new ideas influences innovation and productive efficiency. With this as motivation we use citations to scientific papers to measure the diffusion of science through the U.S. economy. To indicate the speed of diffusion we rely primarily on the modal or most frequent lag. Using this measure we find that diffusion between universities as well as between firms and universities takes an average of three years. The lag on science diffusion between firms is 3.3 years, compared with 4.8 years in technology for the same companies using the same methodology. Industrial science diffuses fifty per cent more rapidly than technology, and academic science diffuses still faster. Thus the priority publication system in science appears to distribute informa...
|November 2004||Standing on Academic Shoulders: Measuring Scientific Influence in Universities|
with James D. Adams, Paula E. Stephan: w10875
This article measures scientific influence by means of citations to academic papers. The data source is the Institute for Scientific Information (ISI); the scientific institutions included are the top 110 U.S. research universities; the 12 main fields that classify the data cover nearly all of science; and the time period is 1981-1999. Altogether the database includes 2.4 million papers and 18.8 million citations. Thus the evidence underlying our findings accounts for much of the basic research conducted in the United States during the last quarter of the 20th century. This research in turn contributes a significant part of knowledge production in the U.S. during the same period.
The citation measure used is the citation probability, which equals actual citations divided by potential cita...