The Spatial Dynamics of the Inventor Network in German Biotechnology: Geographical Proximity Versus Triadic Closure

This paper analyses the spatial dynamics of the inventor network in German biotechnology between 1970 and 1995, aiming to introduce a spatial dimension into the dynamic analysis of innovation networks. After a long-lasting phase of knowledge exploration biotechnology experienced a transition towards increasing knowledge exploitation in the late 1980s. We argue that this transition impacts on the dynamics of the inventor network. On the basis of a patent-based reconstruction of the inventor network and a stochastic estimation model of network evolution, this paper shows that geographical proximity between inventors is mostly relevant in a situation of knowledge exploration, when knowledge is predominantly tacit. By contrast, triadic closure gains relevance in a situation of knowledge exploitation, with higher levels of knowledge codification and the associated risk of unintended and costly knowledge leakages. Accordingly, triadic closure is becoming a more important driver of network dynamics over time.