January 1997, Version 1.01 <p>Prepared for the American Economic Review Papers and Proceedings , May 1997. <p>See also "The Productivity of Nations"

September 24, 1999 -- Version 4.0 <p> At least since 1950, the U.S. economy has benefited from increases in educational attainment, increases in research intensity, and the increased openness and development of the world economy. Such changes suggest, contrary to the conventional view, that the...</p>

September 26, 1996 -- Version 4.00 <p>The recent literature on convergence has departed from the earlier literature by focusing on the shape of the production function and the rate at which an economy converges to its own steady state. This paper uses advances from the recent literature to look...</p>

March 29, 1997, Version 1.0 <p>The post-World War II period has seen substantial changes in the distribution of GDP per worker around the world. In the upper half of the distribution, a number of countries have exhibited large increases in income relative to the richest countries. In the bottom...</p>

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>