Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Research and development is a key determinant of long-run productivity and welfare. A central issue is whether a decentralized economy undertakes too little or too much R&D. We develop an endogenous growth model that incorporates parametrically four important distortions to R&D: the surplus appropriability problem, knowledge spillovers, creative destruction, and duplication externalities. Calibrating the model, we find that the decentralized economy typically underinvests in R&D relative to what is socially optimal. The only exceptions to this conclusion occur when the duplication externality is strong and the equilibrium real interest rate is simultaneously high. Copyright 2000 by Kluwer Academic Publishers