Patent pools, which combine complementary patents of competing firms, are expected to increase overall welfare – but potentially discourage innovation in substitutes for the pool technology. This paper exploits a new historical data set on changes in patenting and firm entry for a clearly...

This paper argues that the ability to keep innovations secret may be a key determinant of patenting. To test this hypothesis, the paper examines a newly-collected data set of more than 7,000 American and British innovations at four world's fairs between 1851 and 1915. Exhibition data show that...

Patent pools allow a group of firms to combine their patents as if they were a single firm. Theoretical models predict that pools encourage innovation in pool technologies, albeit at the cost of innovation in substitutes. Empirical evidence is scarce because modern pools are too recent to allow...