Chapter 19. Econometric Methods for the Analysis of Assignment Problems in the Presence of Complementarity and Social Spillovers Concern over the distributional effects of policies which induce changes in peer group structure or associational redistributions (Durlauf 1996c) motivates a substantial body of theoretical and empirical research in economics sociology psychology and education. A growing collection of econometric methods for characterizing the effects of such policies are now available. This chapter surveys these methods. I discuss the identification and estimation of the distributional effects of partner reassignment in one on one matching models the average outcome and inequality effects of segregation and treatment response in the presence of spillovers.