Geography and Diversity in the Formation of Academic Collaborations Networks

We develop a structural model of dynamic network formation and apply the model to data on academic collaborations. In the model, new connections form randomly with probabilities depending on the existing network, individual characteristics, and geographic and topical distances. Using our model, we estimate parameters determining the effect of each of these factors on link formation using data on formal and informal collaboration in Financial Economics. Our theoretical analysis shows that with high probability, the network will be `close' to a steady state in the sense that researcher's centralities are close to their steady state values. Understanding these steady states lets us determine which researchers will be most central, and thus most productive, in the networks that would form under counterfactual policies (e.g. secession of a country or the absence of gender homophily).