What form of intellectual property rights (IPR) policy contributes to economic growth? Should technological followers be able to license the products of technological leaders? Should a company with a large technological lead receive the same IPR protection as a company with a more limited lead?...

We build a model of firm-level innovation, productivity growth and reallocation featuring endogenous entry and exit. A new and central economic force is the selection between high- and low-type firms, which differ in terms of their innovative capacity. We estimate the parameters of the model...

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...