Matching and Network E¤ects

This paper examines the existence and magnitude of network e¤ects in the matching of workteams. We study the formation of co-author relations among economists over a thirty year period. Our principal …nding is that a collaboration emerges faster among two authors if they are closer in the social network of economists. This proximity e¤ect on collaboration is strong and robust but only a¤ects initial collaboration. It has no positive in‡uence on subsequent co-authorship. We also provide some evidence that matching depends on experience, junior authors being more likely to collaborate with senior authors. JEL codes: J41, L14 Keywords: network formation, assortative matching, scienti…c collaboration, academia, job referral We are grateful for the useful comments received from Fernando Redondo-Vega, Tom Snijders, Markus Mobius, John Harrington, Jean Ensminger, and Je¤ Johnson; from seminar participants in Harvard, Oxford, Utrecht, Alicante, and Essex; and from participants to the Conference on Networks, Behavior, and Poverty held in Oxford in December 2004. We thank the American Economic Association for making the data available. yDepartment of Economics, University of Oxford, Manor Road, Oxford OX1 3UQ. Email: marcel:fafchamps@economics:ox:ac:uk. Fax: +44(0)1865-281447. Tel: +44(0)1865-281446. zTinbergen Institute, Erasmus University Rotterdam. E-mail: [email protected] xDepartment of Economics, University of Essex. E-mail: [email protected]