Identifying social interactions: a review

,Corresponding author. Blume: Department of Economics, Cornell University, Uris Hall, Ithaca, NY; Durlauf: Department of Economics, 1180 Observatory Drive, Madison WI, 53706-1393.The John D. and Catherine T. MacArthur Foundation, National Science Foundation and University of Wisconsin Graduate School have provided financial support. We thank J. Michael Oakes for immensely helpful comments on a previous draft and Buz Brock for many comments on this work. Ethan Cohen-Cole, Giacomo Rondina and Histaoshi Tanaka have provided splendid research assistance.