ABSTRACT
The third line of research is more broad in its scope as it seeks to understand and measure the use and effectiveness of patents in protecting the rents from innovation. Beginning with the early empirical work of Edwin Mansfield (Mansfield et al. 1981; Mansfield 1986), this field of research has grown at a steady pace since the beginning of the 1980s. Theoretical models have focused on the many aspects of patents: how they may modify the incentives to innovate (Gilbert and Newbery 1982), how they may signal significant technological advances and deter further research (Fudenberg et al. 1983) and alternatively, how they may open new avenues of research through disclosure of new scientific discoveries (Choi 1990); how patents are enforced by firms against infringers (Lanjouw and Lerner 1996).
or sought to measure the effectiveness of patents against imitators, most frequently by using survey data (Levin et al. 1987; Cohen et al. 1997).
