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...

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...