Empirics of the identification of social interactions; an evaluation of the approaches and their results

Over the last decade, the study of social interactions in economic decision making has become an important area of research. The main objective of this paper is to survey the extent to which recent empirical contributions have succeeded in overcoming the identification problems as first formulated by Manski (1993). This discussion is followed by a comparison of empirical studies in three key areas of research: neighborhood effects, substance use among teenagers, and peer effects among university roommates. Finally, I discuss questions like: Can economists restrict attention to a specific subcategories of social interactions ? How do we define social groups, and what is the importance of social interactions for public policy.