HETEROGENEOUS PEER EFFECTS AND GENDER- BASED INTERVENTIONS FOR TEENAGE OBESITY

Most of these studies document the presence of positive and significant peer effects which could increase the prevalence of obesity by changing reference norms for body image and/or by boosting the social transmission of unhealthy habits related to diet and physical activity.1 Our paper follows the second strand of the literature by exploring the role of gender heterogeneity in the social diffusio. [...] The upper panel provides the four endogenous peer effects coefficients (standard errors of the estimates are reported in the adjacent columns), namely: the effects of male peers’ BMI on the BMI of male students (m−m, columns 3 and 4), the effects of female peers’ BMI on the BMI of male students (m− f , columns 5 and 6), the effects of female peers’ BMI on the BMI of female students (f −f , columns. [...] The indirect treatment effect, which operates through the change in the treatment status of peers, is the average of the column (or row) sums of the non-diagonal elements of ∂E(y|itt) 27∂itt. [...] The total treatment effect is then calculated as the sum of the direct and the indirect effects.28 26For the sake of simplicity, the only individual attribute we include is the treatment status, and we rule out contextual peer effects. [...] 27The row sum represents the impact of changing the treatment status of all other individuals on the outcome of one particular individual, while the column sum represents the impact of changing the treatment status of one particular individual on the outcome of all other individuals.