Innovation complementarities and firm growth

This article explores the relations between firm growth and a set of four innovation indicators (in-house R&D, external sourcing, product innovation, and process innovation) that capture the different sources, modes, and outcomes of the innovative strategies adopted by firms. While existing studies tend to focus on the individual effects on growth of each innovation activity, we stress that firms adopt heterogeneous innovation strategies, choosing to perform different combinations of the basic innovation activities. We directly address the empirical question as to whether jointly performing two basic innovation activities boosts sales growth above and beyond the separate contribution of each innovation activity when performed individually. Exploiting a panel of Spanish manufacturing firms observed between 2004 and 2011, we document instances of super-modularity of the growth function, and reveal the presence of complementarities between internal R&D and product innovation, and between product and process innovations. As such, the combination of these three basic innovation activities appears to be the most effective strategy for sustaining growth and market shares, while external sourcing does not appear to make any systematic contribution.