Spillovers in product and process innovation: Evidence from manufacturing firms

This paper proposes a new empirical approach to assess the impact of knowledge spillovers on firms' productivity and demand. I consider a model where process innovation spillovers to other firms raise firms' relative efficiency while technological diffusion of product innovations enhances firms' demand. By modelling knowledge capital as a function of own investment in R&D and spillovers, I can compare the impact of these two complementary sources of knowledge on both the supply and the demand side. The results obtained confirm the findings already highlighted by previous empirical studies that technological externalities affect positively firms' productivity growth. The new finding is that product innovations have a larger technological diffusion than process innovations, both in magnitude and pervasiveness. (c) 2005 Elsevier B.V. All rights reserved.