Exploring new aspects of inbound open innovation: the consolidation index

The open innovation literature showed that two approaches to inbound open innovation are likely to enhance innovation performance: using the greater number of external sources, to any degree of intensity (i.e. increase external search breadth); and using the greater number of external sources, to a high degree of intensity (i.e. increase external search depth). This article studies an unexplored third approach to inbound open innovation: using the firm's external sources at the highest degree of intensity. To this aim, it introduces a novel measure of inbound open innovation, the consolidation index. Using a large sample of European firms, this article describes how the consolidation index varies with the firm size, with the innovativeness of the firm’s home country and with the innovativeness of its sector. Finally, it describes its interaction with other inbound open innovation measures and explores its impact on innovation performance.