D. Wayne Osgood

This chapter provides methodological background for aspects of the empirical research presented in this volume that may not be familiar to many of its readers. Beginning with the elements that define a social network, the nature and structure of social network data and the special methodological challenges they present are explained. Shown is how the network data structure provides the basis for measures of position and structure at multiple levels of analysis, from the individual to the entire network. Also described is Simulation Investigation for Empirical Network Analysis (SIENA), the dynamic network analytic approach that is the basis for much of the authors’ research on selection and influence processes. Finally, the chapter includes a section on the use of multilevel modeling, which plays a prominent role in this volume due to PROSPER’s longitudinal, multiple-community research design.

This chapter introduces the volume by describing the origins of the PROSPER (Promoting School-community-university Partnerships to Enhance Resilience) Peers project and presenting the conceptual framework for studying the connections between friendships and risky behavior across adolescence. It begins with the story of the project’s origin as a fortuitous outgrowth of the PROSPER community-level prevention trial. Next, the importance of the topic is discussed in terms of the simultaneous growth during adolescence in the prominence of peers and in many risky behaviors. This in turn has led to an emphasis on peer influence in both explanations of those behaviors and efforts to prevent them. The remainder of the chapter introduces a network-based conceptual framework. It begins with the ways in which a network perspective broadens understanding of peer influence, especially by directing substantive attention to selection processes. The remainder of the chapter presents concepts of network structure and position and of individual, group, and network levels of analysis.

This article delves into the connections between time trends in unstructured socializing and other dramatic changes in adolescence since the 1950s. Osgood et al.’s (1996) individual‐level application of routine activity theory proposed that unstructured socializing contributes to crime by exposing people to situations conducive to deviance, and a large body of research supports this idea. Unstructured socializing has proven useful as an explanatory bridge that links crime and deviance to key social factors like age, class, and gender. The present article expands on two recent studies (Baumer et al., 2021; Svensson & Oberwittler, 2021), which showed that changing rates of unstructured socializing help explain time trends in delinquency as well. Based on time trends across many domains of adolescent life, I argue that changes in unstructured socializing were a manifestation of the rise and fall of a teen culture of independence from the 1950s to the 2020s. The effectiveness of unstructured socializing as an explanatory bridge demonstrates the value of focusing on ordinary, everyday activities for tapping into features of life that are consequential and that vary across social conditions.

Objectives Drawing on criminological research about peer delinquency and self-control, we employ a network perspective to identify the potential paths linking impulsivity, peers, and delinquency. We systematically integrate relevant processes into a set of dynamic network models that evaluate these interconnected pathways. Methods Our analyses use data from more than 14,000 students in Pennsylvania and Iowa collected from the evaluation of the PROSPER partnership model. We estimate longitudinal social network models to disentangle the paths through which impulsivity and delinquency are linked in adolescent friendship networks. Results We find evidence of both peer influence and homophilic selection for both impulsivity and delinquency. Further, results indicate that peer impulsivity is linked to individual delinquent behavior through peer influence on delinquency, but not on impulsivity. Finally, the results suggest that impulsivity moderates both influence and selection processes, as adolescents with higher levels of impulsivity are more likely to select delinquent peers but less likely to change their behavior due to peers. Conclusions In sum, this study offers a more holistic framework and stronger theoretical tests than similar studies of the past. Our results illustrate the need to consider the simultaneous network processes related to peers, impulsivity, and delinquency. Further, our findings reveal that a large dataset with ample statistical power is a valuable advantage for detecting the selection processes that shape friendship networks.

This study examines developmental change across adolescence in the similarity of friends versus nonfriends. This differential in similarity is a key aspect of the organization of the peer context of development: The stronger the correlation between friends for an attribute, the more the attribute delineates clustering and divisions of friendships. We investigated change in the correlation between friends across twelve attributes covering demographics, orientations to key institutions (family, school, religion), and problem behavior, and we expected that the link between similarity and friendship would increase during adolescence for most attributes other than gender. We also predicted that the social ecological factors of school size and attribute variability would be associated with stronger correlations between friends and partially mediate developmental change. Data are from two grade cohorts of 27 small school districts, followed from 6^th through 11^th grades (N = 454 time-specific networks and over 65,000 person/waves of data; 84.2% White, 6.8% Hispanic/Latino, 3.2% African-American, 1.3% Asian, .5% Native American, 3.9% other or multiple). The data analysis takes the form of a three-level random effects meta-analysis of network level correlations between friends (Moran’s I). As expected, declining dominance of gender was offset by the emergence of moderate correlations across a broader profile of attributes. The ecological opportunity factors of grade cohort size and attribute variability significantly mediated these increases in correlations between friends, accounting for 23% to 73% of age-related change for 10 of the 11 attributes other than gender.

The current study compares estimates of peer influence from an analytic approach that explicitly address network processes with those from traditional approaches that do not. Using longitudinal network data from the PROmoting School–community–university Partnerships to Enhance Resilience peers project, we obtain estimates of social influence on multiple outcomes from both conventional linear modeling approaches and the stochastic actor–based modeling approach of the simulation investigation for empirical network analysis (SIENA) software. Our findings indicate that peer influence estimates from SIENA are not more conservative relative to other methods, that each method is subject to omitted variable bias from stable individual differences, and that imprecision among each method could lead to erroneous conclusions in samples that lack sufficient power. Together, these results underscore the difficulty in obtaining estimates of peer influence from observational data, and they give no indication that results from conventional methods tend to be biased toward overestimating peer influence, relative to SIENA.

We examine whether economic crimes are committed to fund drug addiction and/or to fund a hedonistic lifestyle. To address motivation, we estimate reciprocal relationships between economic crime and drug use and between economic crime and hedonistic activity generally. Analyses are based on event calendar data collected from 715 male offenders. Both simultaneous (within-month) relationships and effects involving a 1-month lag are examined. Offenders were more likely to engage in property crime and drug dealing during months in which they used hard drugs, marijuana, and alcohol, and when they engaged in more frequent unstructured socializing. The results from lagged models suggested that hedonistic activities lead to economic crime and economic crime creates opportunities for more frequent hedonistic activity.

This study investigates the influence of structural transitions to high school on adolescents’ friendship networks and academic grades from 6th through 12th grade, in a direct comparison of students who do and do not transition. We utilize data from 14,462 youth in 51 networks from 26 districts (Promoting School–Community Partnerships to Enhance Resilience). Results underscore the challenging nature of compulsory school changes. Students that structurally transition to high school between eighth and ninth grade, as compared with those who do not, receive fewer friendship nominations following the move and are more likely to become isolates, according to a three-level Poisson model. Students who transition also report significantly lower odds of obtaining high grades after the shift, and these penalties persist throughout high school. Our findings highlight the social and academic difficulties associated with this particular normative adolescent life transition and point to a disruption in social network ties as part of the problem.