Evaluation of Community-Level Effects of Communities That Care on Youth Problem Behaviors Using a Repeated Cross-Sectional Design

Introduction: The Communities That Care (CTC) prevention system has shown effects on reducing incidence and prevalence of problem behaviors among a panel of youth followed from 5th through 12th grade in a community-randomized trial. These findings based on the longitudinal panel indicate that CTC affected individuals in the targeted cohort in the community over time. Another option for collecting outcome data in community-randomized trials is a repeated cross-sectional design, which tests intervention effects on community-wide changes in youth outcomes for a specific grade level over time. This study examined whether CTC effects could be observed using a repeated cross-sectional design in the same trial.

Methods: Data were from a community-randomized trial of CTC in 24 small U.S. towns. Cross-sectional samples of 6th, 8th, and 10th graders were surveyed at four biennial waves with sample sizes over survey years ranging from 4,647 to 5,077 for 6th graders, 4,491 to 4,984 for 8th graders, and 3,854 to 4,726 for 10th graders. Two-stage ANCOVA analyses estimated differences between CTC and control communities in community-level prevalence of problem behaviors for each grade, adjusting for prevalence of the same grade level at baseline. Secondary analyses using two-stage ANCOVA models examined intervention effects within a “pseudo cohort” using cross-sectional data from 10th graders to measure outcomes, but adjusting for baseline prevalence of problem behaviors in the community using cross-sectional data collected from the same grade cohort four years earlier when they were in 6^thgrade.

Results: No statistically significant reductions in prevalence of problem behaviors were observed at any grade in CTC compared to control communities using cross-sectional analyses. When examining effects within the “pseudo cohort,” CTC compared to control communities showed a significantly slower increase from 6th to 10th grade in lifetime smokeless tobacco use, but not for other outcomes. Post-hoc analyses showed significantly slower increases in other lifetime problem behaviors including marijuana use within the pseudo cohort for CTC communities with high prevention program saturation compared to control communities.

Conclusions: Although CTC demonstrated effects in a longitudinal panel followed in the same community-randomized trial, we did not find similar effects on problem behaviors using a repeated cross-sectional design. These differences may be due to cohort effects and accretion of those who were not exposed and attrition of those who were exposed to CTC programming in the repeated cross-sectional sample. The presentation will discuss implications for future implementation of CTC.