Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This paper quantifies the effects of exogenous variations in the state of technology (technological opportunity) and of the R&D of other firms (spillovers of R&D) on the productivity of firms' R&D. The R&D productivity is increased by the R&D of "technological neighbors," though neighbors' R&D lowers the profits and market value of low-R&D-intensity firms. Firms are shown to adjust the technological composition of their R&D in response to technological opportunity. Copyright 1986 by American Economic Association.