The evolving structure of the technological landscape.

In this paper, we set out to analyse the evolving structure of the technological landscape on which our knowledge-based economies thrive. To this end, we develop a network-analytic model, which we use to characterise and study the evolving pattern of citations among all patents granted in the USA from 1975 to 1999. We find that (i) the structure of knowledge spillovers among technology domains features the distinguishing properties of a small world topology. However, (ii) during the 25 years observed there has been a consistent trend away from the small world topology, which (iii) is entirely explained by the disappearance of specialties encompassing multiple tightly interconnected technology domains. Our findings bear important strategic implications for both managers and policy makers.