Social interactions in health behaviors and conditions

Abstract

We review the economic literature of the past 20 years on peer effects in health behaviors and conditions. We find consistent evidence of peer effects across a wide range of behaviors and outcomes (alcohol, body weight, food and nutrition, physical fitness, sexual behaviors, fertility, and mental health use) and across a diverse set of identification techniques (instrumental variables, network analysis, reduced form models, random assignment of peers, and discrete choice models of endogenous interactions). Despite the thorough evidence on the existence of peer effects, we still know little about the underlying mechanisms. Understanding these mechanisms is critical for the design of effective policies and constitutes the new stage in the research agenda.