Having the wrong friends? Peer effects in adolescent substance use

Gender, risk perceptions, and smoking behavior

The underlying reasons for gender differences in smoking behavior, and thus for the recent trends, are not well understood. Using a sample of 8592 Swedish adolescents aged 15-18, this paper contributes to the literature by exploring gender differences in smoking risk perceptions and in the responses to the latter. The results show significant gender differences in the perception of smoking mortality risk and in the perception of the addictiveness of smoking. Girls perceive the mortality risk of smoking as significantly greater than boys do, but they also perceive the addictiveness of cigarettes as less. These results persist after controlling for a wide range of background characteristics, including smoking risk information sources. Moreover, the findings suggest that while smoking information from sources such as teachers, pals, and own search, affect smoking mortality perceptions in a significant and positive manner among boys, no such effects are obtained among girls. Finally, our results show that both boys and girls take both the addictiveness and mortality risk of smoking into account when making their smoking decision. Moreover, the magnitude of the response is similar among boys and girls. This is in contrast to the general belief that females dislike risks to a greater extent than males.

Peer effects in adolescent overweight

This study is the first to estimate peer effects for adolescent weight. We use data from the National Longitudinal Study of Adolescent Health (Add Health) and define peer groups using nominated friends within schools. Endogenous peer groups are accounted for using a combination of school fixed effects, instrumental variables, and alternative definitions of peers (i.e., grade-level peers). Mean peer weight is correlated with adolescent weight, even after controlling endogenous peer groups. The impact of peer weight is larger among females and adolescents with high body mass index. The results are consistent with social multipliers for adolescent overweight policies.

Asymmetric peer effects in the analysis of cigarette smoking among young people in the United States, 1992-1999

We extend the recent literature on peer effects to test the possible role of asymmetric social influences in the determination of youth smoking. We analyzed cigarette smoking among people aged 15-24 in approximately 90,000 households in the 1992-1999 U.S. Current Population Surveys. The presence of additional smoking sibling in a household, we estimated, raised a young person's probability of smoking by 7.6%, while each non-smoking sibling lowered the probability by an estimated 3.5%. Moreover, the overall deterrent effect of an increase in cigarette price on the probability of smoking was approximately 60% greater than the estimated effect when peer influences were held constant. The concept of asymmetric social influence may have applications in other fields, including labor economics, education, crime prevention, and group dynamics.

Fraternity membership and binge drinking

This paper examines the relationship that social fraternity and sorority membership has with binge drinking incidence and frequency among 18-24 year old full-time 4-year college students who participated in the 1995 National College Health Risk Behavior Survey. To net out unobserved heterogeneity, several measures of situational and total alcohol use are entered into the regressions as explanatory variables. Fraternity membership coefficients are substantially reduced in size, but remain large and highly significant, suggesting a causal effect on binge drinking. Otherwise, the estimates identify idiosyncratic selection into fraternities and binge drinking across students with similar overall drinking profiles. Particularly notable is that behavior by underage students appears to drive the relationship.

"It wasn't me, it was them!" social influence in risky behavior by adolescents

Many years of concerted policy effort in Western countries has not prevented young people from experimenting with cigarettes, alcohol and marijuana. One potential explanation is that social interactions make consumption "sticky". We use detailed panel data from the Add Health survey to examine risky behavior (the consumption of tobacco, alcohol and marijuana) by American adolescents. We find that, even controlling for school fixed effects, these behaviors are correlated with lagged peer group behavior. Peer group effects are strongest for alcohol use, and young males are more influential than young females. Last, we present some evidence of non-linearities in social interactions.