This paper presents estimates of the long-term impact of various sources of knowledge (R&D performed by the business sector, the public sector and foreign firms) on multifactor productivity growth of 16 countries from 1980 to 1998. The main results show that the three sources of knowledge are...

Economic theory views patents as policy instruments aimed at fostering innovation and diffusion. Three major implications are drawn regarding current policy debates. First, patents may not be the most effective means of protection for inventors to recover R&D investments when imitation is costly...