Innovation, Inequality and Intellectual Property Rights
The existing literature on the sources and nature of productivity growth during the early industrialization stages of U.S. has identified the combination of intellectual property rights (IPRs) with a large middle class and broad participation in markets as explanations for the extraordinary level and growth of patenting. The paper considers whether these factors could play a role in the contemporaneous evolution of innovation in a broad cross section of countries today.
Link
http://econwpa.wustl.edu:80/eps/dev/papers/0410/0410002.pdf