Property Rights and Invention

We survey the economics literature on optimal patent design. We first outline the patent right and the basic economic effects of the patent on innovation. Models that use frictions instead of patents to generate rewards to innovation and models of trade secrecy are considered briefly. The patent design papers are divided into those that model a single innovation, those dealing with cumulative innovation, and more recent papers focussing on complementary innovations. Disclosure issues are presented in a separate section. Finally, enforcement of patents and the interactions between patents and competition policy are considered.