Social Network Methods for Assigning Students to Teams.

Teachers often group students into teams to organize their classrooms and network-informed interventions hold great promise as a way to facilitate positive peer influence and promote the diffusion of intervention effects. Yet thus far, relatively little research has explored how teachers or prevention scientists can best use social network information to assign students to teams. The goal of the present study was to identify and compare seven methods that use different data sources and assignment algorithms to create teams of students. To test these methods, we used survey data from 247 5th through 8th grade students in three rural schools that assessed students' social networks, sociability, values and interests, and bonding to school. To create teams, we first identified popular students (i.e., those who received the highest number of peer nominations) who also had school bonding scores in the normal range and formed 4-person teams around them, applying different methods to assign students to teams. In all but one method, we placed at-risk students (i.e., those who had the lowest school bonding scores) in teams only during the final round of team creation. Team assignments were compared against three criteria: (1) team-level bonding to school, (2) patterns of affiliation among teammates, and (3) shared values and interests. Two methods, one that used only social network data and one that used social network data in combination with students' values and interests, yielded the most promising outcomes. The most positive results were obtained when a pruning algorithm akin to the one proposed by Girvan and Newman (2002) Proceedings of the National Academy ofSciences, 99, 7821-7826 was used to select which dyads to join as teammates; this pruning method joined more weakly linked students first, maximizing their potential to find suitable matches. These methods for team assignment hold promise for designing network-informed school-based interventions.

Social Networks of Adolescent Sexual Violence Perpetrators: Peer Friendship and Trusted Adult Characteristics.

The current study tested differences in social network characteristics of high school students who report perpetrating sexual violence (SV) versus those who do not. N = 4554 students (49% male, 49% female, 2% another gender identity; 45% Hispanic, 43% white, 12% another racial identity) from 20 high schools reported how often they had perpetrated 13 sexually violent behaviors. Using their responses, students were classified as follows: non-perpetrators, sexual harassment perpetrators, low contact perpetrators, or high contact perpetrators. Students named up to 7 close friends and up to 7 trusted adults at their school and answered questions about other behaviors and attitudes. This information was used to assess (1) students' connections with peers, (2) students' connections with trusted adults, and (3) friends' characteristics. Multilevel models indicated that compared to their peers, high contact perpetrators were less involved in the peer networks, less connected to trusted adults, and more likely to have friends who were involved in risky behaviors (e.g., sexual violence, homophobic name-calling, substance use). Low contact perpetrators were as connected to peers and trusted adults as non-perpetrators but were more likely to have friends engaged in sexual violence and homophobic naming-calling perpetration. By contrast, sexual harassment perpetrators were more involved and held higher status in the peer network (e.g., received more friendship nominations) but otherwise had similar friendship characteristics and similar connections to trusted adults as non-perpetrators. Building on these results, social network-informed SV prevention should use opinion leaders to change SV norms throughout the network and encourage new relationships between low- and high-risk students so as to disseminate norms that do not tolerate SV. Promoting connections to trusted adults also may be a useful avenue, especially for isolated adolescents.Trial Registration This study is registered at www.clinicaltrials.gov NCT01672541. Syntax code is available from the authors upon request.

A Hybrid Evaluation-Optimization Trial to Evaluate an Intervention Targeting the Intersection of Alcohol and Sex in College Students and Simultaneously Test an Additional Component Aimed at Preventing Sexual Violence.

BACKGROUND: Using the multiphase optimization strategy (MOST), we previously developed and optimized an online behavioral intervention, itMatters, aimed at reducing the risk of sexually transmitted infections (STI) among first-year college students by targeting the intersection of alcohol use and sexual behaviors. PURPOSE: We had two goals: (a) to evaluate the optimized itMatters intervention and (b) to determine whether the candidate sexual violence prevention (SVP) component (included at the request of participating universities) had a detectable effect and therefore should be added to create a new version of itMatters. We also describe the hybrid evaluation-optimization trial we conducted to accomplish these two goals in a single experiment. METHODS: First year college students (N = 3,098) at four universities in the USA were individually randomized in a hybrid evaluation-optimization 2 × 2 factorial trial. Data were analyzed using regression models, with pre-test outcome variables included as covariates in the models. Analyses were conducted separately with (a) immediate post-test scores and (b) 60-day follow-up scores as outcome variables. RESULTS: Experimental results indicated a significant effect of itMatters on targeted proximal outcomes (norms) and on one distal behavioral outcome (binge drinking). There were no significant effects on other behavioral outcomes, including the intersection of alcohol and sexual behaviors. In addition, there were mixed results (positive short-term effect; no effect at 60-day follow-up) of the SVP component on targeted proximal outcomes (students' self-efficacy to reduce/prevent sexual violence and perceived effectiveness of protective behavioral strategies). CONCLUSIONS: The hybrid evaluation-optimization trial enabled us to evaluate the individual and combined effectiveness of the optimized itMatters intervention and the SVP component in a single experiment, conserving resources and providing greatly improved efficiency. TRIAL REGISTRATION: NCT04095065.

Moderators of Friend Selection and Influence in Relation to Adolescent Alcohol Use.

Friendships form an important context in which adolescents initiate and establish alcohol use patterns, but not all adolescents may be equally affected by this context. Therefore, this study tests whether parenting practices (i.e., parental discipline, parental knowledge, unsupervised time with peers) and individual beliefs (i.e., alcohol descriptive norms, positive social expectations, moral approval of alcohol use) moderate friend selection and influence around alcohol use. Stochastic actor-based models were used to analyze longitudinal social network and survey data from 12,335 adolescents (aged 11 to 17, 51.3% female) who were participating in the PROSPER project. A separate model was estimated for each moderating variable. Adolescents who reported consistent parental discipline, less unsupervised time with peers, higher descriptive alcohol use norms, and less positive social expectations about alcohol use were less likely to select alcohol-using friends. Those who reported consistent parental discipline, better parental knowledge, lower descriptive alcohol use norms, and less positive social expectations were more influenced by their friends' level of alcohol use. Thus, adolescents with these characteristics whose friends frequently use alcohol are at greater risk whereas those whose friends do not use alcohol are at lower risk of using alcohol. The findings show that, although selection and influence processes are connected, they may function in different ways for different groups of adolescents. For some adolescents, it is particularly important to prevent them from selecting alcohol-using friends, because they are more susceptible to influence from such friends. These peer network dynamics might explain how proximal outcomes targeted by many prevention programs (i.e., parenting practices and individual beliefs) translate into changes in alcohol use.

Laying the groundwork for evidence-based public health: why some local health departments use more evidence-based decision-making practices than others.

We examined variation in the use of evidence-based decision-making (EBDM) practices across local health departments (LHDs) in the United States and the extent to which this variation was predicted by resources, personnel, and governance. We analyzed data from the National Association of County and City Health Officials Profile of Local Health Departments, the Association of State and Territorial Health Officials State Health Departments Profile, and the US Census using 2-level multilevel regression models. We found more workforce predictors than resource predictors. Thus, although resources are related to LHDs' use of EBDM practices, the way resources are used (e.g., the types and qualifications of personnel hired) may be more important.

Adolescent peer networks and the potential for the diffusion of intervention effects.

Many evaluation studies assess the direct effect of an intervention on individuals, but there is an increasing interest in clarifying how interventions can impact larger social settings. One process that can lead to these setting-level effects is diffusion, in which intervention effects spread from participants to non-participants. Diffusion may be particularly important when intervention participation rates are low, as they often are in universal family based prevention programs. We drew on socialization and diffusion theories to articulate how features of peer networks may promote the diffusion of intervention effects. Then, we tested the measurement properties of ten social network analytic (SNA) measures of diffusion potential. Data were from 42 networks (n = 5,784 students) involved in the PROSPER intervention trial. All families of sixth-grade students were invited to participate in a family based substance use prevention program, and 17 % of the families attended at least one session. We identified two dimensions of network structure--social integration and location of intervention participants in their peer network--that might promote diffusion. Analyses demonstrated that these SNA measures varied across networks and were distinct from traditional analytic measures that do not require social network analysis (i.e., participation rate, how representative participants are of the broader population). Importantly, several SNA measures and the global network index predicted diffusion over and above the effect of participation rate and representativeness. We conclude by recommending which SNA measures may be the most promising for studying how networks promote the diffusion of intervention effects and lead to setting-level effects.

A randomized iterative approach to optimizing an online substance use intervention for collegiate athletes.

BACKGROUND: Rates of drug use among collegiate athletes are high, yet there are few evidence-based interventions for this population. myPlaybook, an online intervention for collegiate athletes, targets multiple predictors of drug use (i.e., norms, positive and negative expectancies about use, and harm prevention intentions). PURPOSE: We aimed to optimize modules from myPlaybook. METHOD: We evaluated modules through three sequential randomized factorial trials, using the Multiphase Optimization Strategy framework. We recruited and randomized 54 (Trial 1), 47 (Trial 2), and 42 (Trial 3) schools and invited all first-year and transfer collegiate athletes to participate. Athletes completed a baseline survey, their randomly assigned modules, and immediate posttest and 30-day follow-up surveys. Across trials, 3,244 (48.8% female), 2,837 (51.9% female), and 2,193 (51.4% female) athletes participated. In Trial 1, we evaluated and revised less effective modules (defined as d < 0.3-0.4 for targeted outcomes). In Trial 2, we re-evaluated and revised less effective modules. In Trial 3, we re-evaluated the revised modules. RESULTS: Trial 1: All effects were d < 0.15, so we revised modules to target proximal outcomes (i.e., the hypothesized mediating variables in our conceptual model), rather than specific drug use behaviors. Trial 2: Most effects were d < 0.3, so we revised all modules. Trial 3: The norms module improved descriptive and injunctive norms (all d >0.35). The expectancies module improved alcohol positive expectancies (d = 0.3). The other modules were not effective. CONCLUSIONS: After three trials, two myPlaybook modules substantially improved proximal outcomes, increasing the likelihood that the combined intervention will have a meaningful clinical impact on collegiate athletes' drug use.

Rates of drug use among collegiate athletes are high, yet there are few evidence-based interventions for this population, and the few existing interventions only address alcohol use. In addition, alcohol and drug use interventions targeting college students are not always as effective or efficient as they could be. Our goal was to strengthen modules from myPlaybook, an online drug use intervention for collegiate athletes as a way to optimize the full intervention package. We conducted three intervention trials. Each trial occurred in separate academic years and included 2,000­3,000 athletes from 40 to 50 colleges and universities. We randomly assigned athletes to receive one or more intervention modules that target known risk factors for drug use (i.e., social norms, expectancies about the effects of drug use, harm prevention strategies, and life skills). We used the results about the effects of each module to improve the module prior to the next trial. After these trials, the revised modules targeting social norms and expectancies about drug use had meaningful effects, increasing the likelihood that the full myPlaybook intervention will lead to clinical reductions in drug use among collegiate athletes.

An Intervention for the Transition From Pediatric or Adolescent to Adult-Oriented HIV Care: Protocol for the Development and Pilot Implementation of iTransition.

BACKGROUND: In the United States, adolescents and young adults are disproportionately affected by HIV and have poorer HIV-related health outcomes than adults. Health care transition (HCT) from pediatric or adolescent to adult-oriented HIV care is associated with disruptions to youths' care retention, medication adherence, and viral suppression. However, no evidence-based interventions exist to improve HCT outcomes for youth living with HIV. OBJECTIVE: There are 2 phases of this project. Phase 1 involves the iterative development and usability testing of a Social Cognitive Theory-based mobile health (mHealth) HIV HCT intervention (iTransition). In phase 2, we will conduct a pilot implementation trial to assess iTransition's feasibility and acceptability and to establish preliminary efficacy among youth and provider participants. METHODS: The iterative phase 1 development process will involve in-person and virtual meetings and a design team comprising youth living with HIV and health care providers. The design team will both inform the content and provide feedback on the look, feel, and process of the iTransition intervention. In phase 2, we will recruit 100 transition-eligible youth across two clinical sites in Atlanta, Georgia, and Philadelphia, Pennsylvania, to participate in the historical control group (n=50; data collection only) or the intervention group (n=50) in a pilot implementation trial. We will also recruit 28 provider participants across the pediatric or adolescent and adult clinics at the two sites. Data collection will include electronic medical chart abstraction for clinical outcomes as well as surveys and interviews related to demographic and behavioral characteristics; Social Cognitive Theory constructs; and intervention feasibility, acceptability, and use. Analyses will compare historical control and intervention groups in terms of HCT outcomes, including adult care linkage (primary), care retention, and viral suppression (secondary). Interview data will be analyzed using content analysis to understand the experience with use and acceptability. RESULTS: Phase 1 (development) of iTransition research activities began in November 2019 and is ongoing. The data collection for the phase 2 pilot implementation trial is expected to be completed in January 2023. Final results are anticipated in summer 2023. CONCLUSIONS: The development and pilot implementation trial of the iTransition intervention will fill an important gap in understanding the role of mHealth interventions to support HCT outcomes for youth living with HIV. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/24565.

Rejection, feeling bad, and being hurt: using multilevel modeling to clarify the link between peer group aggression and adjustment.

The association between affiliating with aggressive peers and behavioral, social and psychological adjustment was examined. Students initially in 3rd, 4th, and 5th grade (N = 427) were followed biannually through 7th grade. Students' peer-nominated groups were identified. Multilevel modeling was used to examine the independent contributions of adolescents' typical peer context (between-person effect) and changes in peer context (within-person effects) to adolescents' adjustment. Typically affiliating with aggressive groups and affiliating with more aggressive groups than usual predicted higher aggression for all youth. Typically affiliating with aggressive groups predicted negative adjustment (lower social preference and self-worth, higher victimization) for girls but neutral or positive adjustment for boys. Although typical peer context was consistently associated with adjustment, changes in peer context predicted small changes in adjustment for several outcomes. Results underscored the need to adopt a more differentiated picture of adolescents' dynamic peer context and its association with normative development.

Estimation of a four-parameter item response theory model.

We explore the justification and formulation of a four-parameter item response theory model (4PM) and employ a Bayesian approach to recover successfully parameter estimates for items and respondents. For data generated using a 4PM item response model, overall fit is improved when using the 4PM rather than the 3PM or the 2PM. Furthermore, although estimated trait scores under the various models correlate almost perfectly, inferences at the high and low ends of the trait continuum are compromised, with poorer coverage of the confidence intervals when the wrong model is used. We also show in an empirical example that the 4PM can yield new insights into the properties of a widely used delinquency scale. We discuss the implications for building appropriate measurement models in education and psychology to model more accurately the underlying response process.

Using the Integrated Behavioral Model to Determine Sport-Related Concussion Reporting Intentions Among Collegiate Athletes.

PURPOSE: A significant proportion of sport-related concussions goes unreported among adolescents, which can result in irreversible brain damage. It is critical to identify and intervene on factors that significantly impact concussion reporting. METHODS: This study tests factors associated with collegiate athletes' intentions to (1) self-report concussion symptoms; (2) report another athlete's concussion symptoms; and (3) encourage others to report. Drawing on the Integrated Behavioral Model, predictors at the athlete level included perceived norms (bystander descriptive norms, injunctive norms, and subjective norms), attitudes (positive and negative expectancies about reporting and playing through a concussion and concussion reporting attitudes), personal agency (self-efficacy to recognize symptoms and communicate), and perceived coach communication. At the team level, coaches' self-reported communication was also included. Athletes (N = 1,858) and coaches (N = 254) at 16 colleges and universities completed Web-based surveys in 2016. Multilevel modeling accounted for the nesting of athletes within athletic team. RESULTS: Bystander descriptive norms, positive reporting expectancies, concussion reporting attitudes, self-efficacy to communicate about a concussion, and athletes' perceptions of their coach's communication were positively associated with all three outcomes. By contrast, subjective norms were only positively associated with intentions to self-report and bystander reporting intentions, negative reporting expectancies were only associated with intentions to self-report, and positive and negative expectancies for playing through a concussion were only associated with intentions to self-report and bystander encouragement. CONCLUSIONS: In sum, multiple factors within the Integrated Behavioral Model predict reporting intentions and underscore the complexity of athletes' concussion reporting behaviors and offer guidance for the development of prevention strategies.

I've Fallen and I Can't Get Up: Can High Ability Students Recover From Early Mistakes in CAT?

A difficult result to interpret in Computerized Adaptive Tests (CATs) occurs when an ability estimate initially drops and then ascends continuously until the test ends, suggesting that the true ability may be higher than implied by the final estimate. We explain why this asymmetry occurs and show that early mistakes by high ability students can lead to considerable underestimation, even in tests with 45 items. The opposite response pattern, where low ability students start with lucky guesses, leads to much less bias. We show that using Barton and Lord's (1981) four-parameter model and a less informative prior can lower bias and RMSE for high ability students with a poor start, as the CAT algorithm ascends more quickly after initial underperformance. We also show that the 4PM slightly outperforms a CAT in which less discriminating items are initially used. The practical implications and relevance for psychological measurement more generally are discussed.

A reputation for success (or failure): the association of peer academic reputations with academic self-concept, effort, and performance across the upper elementary grades.

The associations between children's academic reputations among peers and their academic self-concept, effort, and performance were examined in a longitudinal study of 427 students initially enrolled in Grades 3, 4, and 5. Assessments were completed in the fall and spring of 2 consecutive school years and in the fall of a 3rd school year. Peer academic reputation (PAR) correlated moderately strongly with teacher-rated skills and changed over time as a function of grades earned at the prior assessment. Path-analytic models indicated bidirectional associations between PAR and academic self-concept, teacher-rated academic effort, and grade point average. There was little evidence that changes in self-concept mediated the association between PAR and effort and GPA or that changes in effort mediated the association between PAR and GPA. Results suggest that peers may possess unique information about classmates' academic functioning, that children's PARs are psychologically meaningful, and that these reputations may serve as a useful marker of processes that forecast future academic engagement and performance.

Diffusion of a Peer-Led Suicide Preventive Intervention Through School-Based Student Peer and Adult Networks.

Background: Peer-led interventions have been applied to prevent various health behavior problems and may be an important complement to individual-level suicide prevention approaches. Sources of Strength trains student "peer leaders" in secondary schools to conduct prevention activities that encourage other students to build healthy social bonds and strengthen help-seeking norms. Prior work examining diffusion of peer-led programs has focused on youths' closeness to peer leaders but minimally on other factors such as connections to adults and suicidal behavior. Methods: We examined implementation and dissemination of Sources of Strength in 20 schools. Over 1 year 533 students were trained as peer leaders and 3,730 9th-12th graders completed baseline surveys assessing friendships and adults at school, and suicidal thoughts/behaviors; and end-of-year surveys reporting intervention exposure: viewed poster/video, attended presentation, direct peer communication, and activity participation. Chi-square tests compared exposure rates by student and network characteristics. Multi-level logistic regression models tested predictors of exposure across individual and school-level characteristics. Results: Exposure to the intervention varied greatly by school and by individual student characteristics and network position. Training more peer leaders increased school-wide exposure for all modalities except presentation (Bs 0.06-0.10, p's < 0.05). In multivariate models, exposure was consistently higher for students closer to peer leaders in the friendship network (ORs 1.13-1.54, p's < 0.05) and students who named more trusted adults (ORs 1.08-1.16, p's < 0.001); and lower for males (ORs 0.56-0.83, p's < 0.05). In multivariate models, training more students as peer leaders predicted exposure to poster-video and direct peer communication in larger schools (OR = 3.34 and 2.87, respectively). Network characteristics influenced exposure similarly for students with suicidal thoughts and behaviors. Discussion: Our findings confirm prior work showing the importance of personal affiliations to peer leaders and natural networks as a medium for diffusion of peer-led prevention efforts. We build on that work by showing independent effects of closeness to adults at school and number of peer leaders trained. There is a need to strategically select peer leaders to maximize closeness to students school-wide, particularly in larger schools. Additional work is required for Sources of Strength to devise messaging strategies to engage males and students isolated from adults at school.

Perceived norms and alcohol use among first-year college student-athletes' different types of friends.

OBJECTIVE: To describe first-year college student-athletes' friendship contexts and test whether their perceptions of alcohol use and approval by different types of friends are associated with their own alcohol use. PARTICIPANTS: First-year student-athletes (N = 2,622) from 47 colleges and universities participating in National Collegiate Athletic Association (NCAA) sports during February-March 2013. METHODS: Student-athletes completed online surveys during the baseline assessment of an alcohol and other drug prevention program evaluation. Analyses tested whether perceptions of friends' alcohol use (descriptive norms) and perceptions of friends' approval of alcohol use (injunctive norms) predicted their alcohol use. RESULTS: Both use and approval perceptions by upperclassmen, same-team, and most influential friends significantly predicted alcohol use. By contrast, only perceived use by first-year, nonteam, and less influential friends significantly predicted alcohol use. CONCLUSIONS: Athletics departments' alcohol policies and prevention programming for first-year student-athletes should address the potential influence of different types of friends on alcohol use.

Parental Influence on Drinking Behaviors at the Transition to College: The Mediating Role of Perceived Friends' Approval of High-Risk Drinking.

OBJECTIVE: This study tested whether perceived parental approval of high-risk drinking is directly linked to alcohol-related outcomes or whether the link between perceived parental approval and these outcomes is mediated by perceived friends' approval of high-risk drinking. METHOD: In fall 2009, 1,797 incoming first-year college students (49.7% female) from 142 U.S. colleges and universities completed a web-based survey before participating in an online substance use prevention program. The analytic sample included only 18- to 20-year-old freshmen students who had consumed alcohol in the past year. Students answered questions about perceived parental approval and perceived friends' approval of high-risk drinking. They also answered questions about their alcohol use (heavy episodic drinking, risky drinking behaviors), use of self-protective strategies (to prevent drinking and driving and to moderate alcohol use), and negative alcohol-related consequences (health, academic and work, social consequences, and drinking and driving). RESULTS: Mediation analyses controlling for the clustering of students within schools indicated that perceived parental approval was directly associated with more easily observable outcomes (e.g., academic- and work-related consequences, drinking and driving). Perceived friends' approval significantly mediated the link between perceived parental approval and outcomes that are less easily observed (e.g., alcohol use, health consequences). CONCLUSIONS: During the transition to college, parents may influence students' behaviors both directly (through communication) as well as indirectly (by shaping their values and whom students select as friends). Alcohol use prevention programs for students about to start college should address both parental and friend influences on alcohol use.

Does Neighborhood Risk Explain Racial Disparities in Low Birth Weight among Infants Born to Adolescent Mothers?

STUDY OBJECTIVE: To test associations and interactions between racial identification, neighborhood risk, and low birth weight disparities between infants born to African-American and white adolescent mothers. DESIGN: Retrospective cross-sectional study. Birth cases were geocoded and linked to census tract information from the 2010 US Census and the 2007-2011 American Community Survey. A "neighborhood risk" index was created using principal component analysis, and mothers were grouped into 3 neighborhood risk levels (low, medium, high). Multilevel models with cross-level interactions were used to identify variation in racial differences in low birth weight outcomes across neighborhood risk levels when controlling for maternal demographic characteristics and pregnancy behaviors (smoking, prenatal care use). SETTING: North Carolina, United States. PARTICIPANTS: Singleton infants (n = 7923 cases) born to non-Hispanic African American and white adolescent mothers from the North Carolina State Center of Health Statistics for 2011. MAIN OUTCOME MEASURES: Low birth weight. RESULTS: African American mothers were significantly more likely to have infants of low birth weight than white mothers in this sample (odds ratio = 1.89; 95% confidence interval, 1.53-2.34). Mothers that resided in areas of high neighborhood risk were significantly more likely to have infants of low birth weight than mothers residing in areas of low neighborhood risk (odds ratio = 1.55; 95% confidence interval, 1.25-1.93). Even when controlling for confounding factors, racial disparities in low birth weight odds did not significantly vary according to neighborhood risk level. CONCLUSION: Racial disparities can remain in low birth weight odds among infants born to adolescent mothers when controlling for maternal characteristics, pregnancy behaviors, and neighborhood risk.

Diffusion of Intervention Effects: The Impact of a Family-Based Substance Use Prevention Program on Friends of Participants.

PURPOSE: We tested whether effects of the Strengthening Families Program for Youth 10-14 (SFP10-14) diffused from intervention participants to their friends. We also tested which program effects on participants accounted for diffusion. METHODS: Data are from 5,449 students (51% female; mean initial age = 12.3 years) in the PROmoting School-community-university Partnerships to Enhance Resilience community intervention trial (2001-2006) who did not participate in SFP10-14 (i.e., nonparticipants). At each of five waves, students identified up to seven friends and self-reported past month drunkenness and cigarette use, substance use attitudes, parenting practices, and unsupervised time spent with friends. We computed two measures of indirect exposure to SFP10-14: total number of SFP-attending friends at each wave and cumulative proportion of SFP-attending friends averaged across the current and all previous post-intervention waves. RESULTS: Three years post-intervention, the odds of getting drunk (odds ratio = 1.4) and using cigarettes (odds ratio = 2.7) were higher among nonparticipants with zero SFP-attending friends compared with nonparticipants with three or more SFP-attending friends. Multilevel analyses also provided evidence of diffusion: nonparticipants with a higher cumulative proportion of SFP-attending friends at a given wave were less likely than their peers to use drugs at that wave. Effects from SFP10-14 primarily diffused through friendship networks by reducing the amount of unstructured socializing (unsupervised time that nonparticipants spent with friends), changing friends' substance use attitudes, and then changing nonparticipants' own substance use attitudes. CONCLUSIONS: Program developers should consider and test how interventions may facilitate diffusion to extend program reach and promote program sustainability.

Race, Socioeconomic Status, and Age: Exploring Intersections in Preterm Birth Disparities among Teen Mothers.

Few studies have examined disparities in adverse birth outcomes and compared contributing socioeconomic factors specifically between African-American and White teen mothers. This study examined intersections between neighborhood socioeconomic status (as defined by census-tract median household income), maternal age, and racial disparities in preterm birth (PTB) outcomes between African-American and White teen mothers in North Carolina. Using a linked dataset with state birth record data and socioeconomic information from the 2010 US Census, disparities in preterm birth outcomes for 16,472 teen mothers were examined through bivariate and multilevel analyses. African-American teens had significantly greater odds of PTB outcomes than White teens (OR = 1.38, 95% CI 1.21, 1.56). Racial disparities in PTB rates significantly varied by neighborhood income; PTB rates were 2.1 times higher for African-American teens in higher income neighborhoods compared to White teens in similar neighborhoods. Disparities in PTB did not vary significantly between teens younger than age 17 and teens ages 17-19, although the magnitude of racial disparities was larger between younger African-American and White teens. These results justify further investigations using intersectional frameworks to test the effects of racial status, neighborhood socioeconomic factors, and maternal age on birth outcome disparities among infants born to teen mothers.