Determinants of R&D and Its Productivity: Identifying Demand and Supply Channels (First revision)

Identifying whether an exogenous factor affects R&D from a demand side or from a supply side is an important issue. This paper, first, theoretically shows that a favorable change in either side can reduce the R&D productivity in equilibrium, so that the reduced form estimation cannot provide a clear identification. Secondly, it estimates both structural and reduced form patent production functions, based on instrumental variables approach, using a large database on Japanese firms. According to the estimation, while the initial firm size, market concentration or export orientation increases R&D, none of them significantly shifts the structural patent production function.