July 6, 1999 <p> Research and development (R&D) 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...</p>

February 26, 1996, Version 5.00 <p> Empirical research in the micro productivity literature consistently supports the notion that there is too little R&D. However, the methodology of this literature, based on the neoclassical growth model, is challenged by new growth theory, which emphasizes a...</p>

January 24, 1997, Version 2.00 <p> Is there too much or too little private research and development (R&D)? A large empirical literature reports estimates of the rate of return to R&D ranging from 30% to over 100%, supporting the notion that there is too little private investment in research....</p>