The catalysing role of in-house R&D in fostering complementarity among innovative inputs

While several studies have investigated the relationship between internal and external sources of innovation, no clear-cut result has emerged so far, suggesting the possibility that the nature of such interaction-far from being an absolute property of the innovative process-may instead be a relative one, contingent upon the nature and the level of innovative inputs a firm has invested in. Using microdata from the third Italian Community Innovation Survey, we test under what conditions the nature of the interactions between four different innovative inputs (internal and external R&D, embodied and disembodied technological acquisition) is one of complementarity or substitutability. Two are the main findings of our study: (i) internal R&D and embodied technological acquisitions turn out to be complementary only after a minimum threshold of in-house R&D expenditure has been overcome, being substitutive otherwise; (ii) investing in internal R&D also affects the nature of the relationships between alternative external sources of innovation, whose interaction proves to be complementary only for firms that invest in internal R&D.