While there is widespread agreement among economists and management scholars that knowledge spillovers exist and have important economic consequences, researchers know substantially less about the "micro mechanisms" of spillovers -- about the degree to which they are geographically localized,...

Understanding factors affecting the direction of innovation is a central aim of research in the economics of innovation. Progress on this topic has been inhibited by difficulties in measuring distance and movement in knowledge space. We describe a methodology that infers the mapping of the...