We formulate a model that explicitly separates two functions in the innovation process: The introduction of new goods and the quality improvement of existing goods. While the latter is performed by the corporate R&D sector, the first is performed by entrepreneurs. We show that in a three sector...

In this paper we suggest an structural model that specifies firm growth as a function of firm specific parameters and of competition for purchase power with other firms on a given market. Moreover, we explicitely model firms? innovative behaviour and distinguish between dierent innovation...