Saturday, February 18, 2017
Exhibit Hall (Hynes Convention Center)
Kathryn M. Barker, Harvard T.H. Chan School of Public Health, Boston, MA
BACKGROUND: Early initiation of sexual behavior is associated with adverse health outcomes such as STIs, poor mental health and unintended pregnancies. The sexual behavior of teens’ peers has been shown to be an important predictor of age sexual initiation. Other studies, however, point to the importance of schools and neighborhoods. To date, no study has considered all of these contexts simultaneously. As such, little is known about the relative importance of peer influences on age at sexual initiation. METHODS: This study draws on a novel analytic approach – the combination of social network community detection analyses and cross-classified multilevel modeling – to compare the relative contributions of each context to the total variation in age at sexual debut. Social network communities are groups of individuals within broader social networks who are densely connected to each other (such as a group of friends and their friend’s friends); these individuals may serve as normative references for individual-level behavior, and represent a potentially more meaningful unit of analysis in the study of peer effects than traditional measures of close friends or schoolmates. Wave 1 of the National Longitudinal Study of Adolescent to Adult Health is used, and for robustness the analysis is conducted in both the core sample (122 schools; N = 14144) and a sub-set known as the saturated sample (16 schools; N = 3335) due to its completeness of neighborhood data. RESULTS: After adjusting for relevant covariates, we find that the school-level and neighborhood-level contributions to the variance are modest as compared with the network community-level. These results are robust to two alternative algorithms for specifying network communities, and to analysis in the saturated sample. Peer influences (measured by the social network community) contribute far more to the total variance in age at sexual debut than either neighborhoods or schools. CONCLUSIONS: Conclusions are to be drawn from both empirical and analytic standpoints. First, while this study does not determine whether network effects are attributable to social influence or selection, it does highlight the relative importance of adolescent social networks in age at sexual debut and indicates that they may be a promising context to address in the design of health promotion programs. From an analytic standpoint, these findings support the claim that omitting potentially salient contexts from analysis may result in the misattribution of variance to the contexts that are considered.