Due to improving information technology, the growing complexity of research problems, and policies designed to foster interdisciplinary research, the practice of science in the United States has recently undergone significant structural change. Using a sample of 110 top US universities observed...

More rapid diffusion of science increases technological opportunity and innovation. To measure the diffusion of science, we use the lag between citing and cited scientific papers. With data from 1981 to 1999, the lag averages 6 years, increases with citation delay, and decreases with firm...

This paper studies geographic localization of academic and industrial knowledge spillovers. Using data on US research and development laboratories that quantify spatial aspects of learning about universities and firms as well as the locations of closely affiliated universities and firms, I find...

We find that the effects of parent firm R&D on plant-level productivity are diminished by both the geographic and technological distance between the research lab and the plants; that productivity appears to depend on R&D per plant rather than on the total amount; and that spillovers from...

This paper considers research performance of U.S. universities for eight science fields. At the aggregate level we find that research output follows a constant returns to scale process. However, for individual universities we find evidence of diminishing returns. We offer two explanations for...