We study how exploration versus exploitation innovations impact economic growth through a tractable endogenous growth framework that contains multiple innovation sizes, multi-product firms, and entry/exit. Firms invest in exploration R&D to acquire new product lines and exploitation R&D to...

Soviet growth over 1960-89 was the worst in the world after we control for investment and human capital; the relative performance worsens over time. The declining Soviet growth rate over 1950-87 is explained by the declining marginal product of capital; the rate of TFP growth is roughly constant...

We examine the golden age of U.S. innovation by undertaking a major data collection exercise linking historical U.S. patents to state and county-level aggregates and matching inventors to Federal Censuses between 1880 and 1940. We identify a causal relationship between patented inventions and...