Many studies investigate the relationship between R&D expenditures as an input and patents as an intermediate product or output of a knowledge production function. We suggest that the productivity of research in patent production functions has been underestimated in the literature, as scholars...

The theoretical discussion concerning the question whether the incumbent or the (potential) entrant invests more into R&D has attracted considerable interest. This paper reports the results of an empirical study on this question using data of about 3500 German firms over the years 1992 to 1995....