When Do Global Pipelines Enhance the Diffusion of Knowledge in Clusters?

Recent studies have stressed the role played by global pipelines in fostering the growth of clusters and innovativeness. In this article, we develop a formal model to investigate when global pipelines contribute to an increase in local knowledge, depending on various characteristics of clusters such as size, knowledge endowment, and the ease of transmission of internal knowledge. This model is an extension of Cowan and Jonard's () model in which we introduce the concept of cluster and a role for spatial proximity in the diffusion of knowledge. Our results reveal that there is a natural tendency of actors within global pipelines to act as external stars, rather than gatekeepers of knowledge. Global pipelines are beneficial for the accumulation of knowledge only if the cluster is either characterized by a high-quality local buzz or is small and weakly endowed in terms of knowledge.