Early Considerations, Long-Term Gains: Evidence and Implications from a Trauma-Informed Behavioral Intervention

Background and Purpose: Schools in the United States (U.S.) are experiencing increasing behavioral and mental health needs among students. Multi-Tiered Systems of Support (MTSS) have emerged as a widely adopted framework to address these challenges; however, rigorous evaluations of specific school-based, trauma-informed interventions remain limited. The Behavior Intervention Support Team (BIST) model is a relationship-centered, trauma-informed, schoolwide intervention designed to improve student self-regulation, reduce exclusionary discipline, and strengthen school climate. Grounded in developmental and behavioral theory, BIST emphasizes early identification of disruptive behaviors, consistent educator responses, and skill-building through a tiered support system. Despite its growing implementation across U.S. schools, limited empirical evidence exists regarding its longitudinal effectiveness on key disciplinary outcomes.

Methods: This study employed a longitudinal quasi-experimental design using seven years (2017–2024) of state administrative data from 333 public schools in a Midwestern state. The sample included 136 schools implementing BIST (treatment) and 197 propensity score-matched (PSM) comparison schools receiving services as usual. Baseline equivalence was established across key school characteristics, and mixed-effects negative binomial regression models accounted for overdispersion and clustering within schools overtime. Outcomes examined include: (1) total number of disciplinary incidents resulting in classroom removal; (2) cumulative days removed; and (3) total number of students involved in disciplinary incidents. The primary independent variable captured years of BIST implementation, categorized to assess early-, mid-, and late-stage effects while controlling for demographic (e.g., race, students receiving free-and-reduced-lunch; and students with formal individualized education plans [IEPs]) and contextual covariates (e.g., school type, year).

Results: Findings revealed a nonlinear, implementation-dependent pattern between BIST implementation and disciplinary outcomes. During the first year of implementation, BIST schools experienced significantly higher rates of total disciplinary incidents (IRR=1.25, p<.05), total days removed (IRR=1.22, p<.05), and total number of students involved (IRR=1.17, p<.05) relative to comparison schools. Similar patterns persisted into the second year for select outcomes. In contrast, mid-stage implementation (6–11 years) was associated with meaningful reductions, including a 38% decrease in total days removed (IRR=0.62, p<.10), with additional non-significant but substantively important declines observed in total number of incidents and students affected. No statistically significant differences were observed for schools with 12+ years of implementation. Covariate analyses revealed significantly higher rates of disciplinary outcomes in middle and high schools compared to elementary schools. Further, students with IEPs, from low-income backgrounds, and students of color were associated with significantly increased disciplinary outcomes.

Conclusions and Implications: Findings suggest BIST implementation may initially increase disciplinary reporting but is associated with substantive improved outcomes over time, particularly with sustained implementation. For school social work, these results underscore the importance of long-term investment in relationship-centered, trauma-informed approaches that promote equity and reduce exclusionary discipline, thereby enhancing student learning and overall school climate. Implications highlight the need for ongoing training and interdisciplinary collaboration to maximize effectiveness. Policymakers and practitioners should consider the delayed impact of such interventions and avoid premature evaluations based on short-term outcomes, particularly in the context of increasing student mental health needs and persistent systemic inequities in schools.