Acceptability, Relevance, and Short-Term Outcomes of the STAC-T Bullying Bystander App: Feasibility Quantitative Study.

Background: Bullying is a significant public health issue, with approximately 25% of middle school students reporting being a target of bullying in the past year. Students who are targets of bullying or witness bullying are at high risk for negative mental health outcomes, including depression and anxiety. STAC is an evidence-based bullying bystander intervention for middle school students, with program outcomes that include reductions in bullying perpetration and victimization, as well as associated mental health risks. We developed a technology-based version of STAC (STAC-T) to reduce implementation barriers associated with in-person bullying prevention programs. STAC-T is an interactive app that includes a 40-minute training and a 15-minute booster session. Objective: This study aimed to evaluate the acceptability and relevance of the STAC-T program. We were also interested in how program acceptability and relevance are related to the use of specific bystander intervention skills (eg, STAC strategies) students learn in the program. Methods: This study was part of a larger study in which students recruited from 6 middle schools in rural, low-income communities in the United States were randomized to either the STAC-T intervention or a control condition. Participants in this study were 229 students in the intervention group who completed the 30-day follow-up survey, including the acceptability and relevance questionnaire. The survey assessed program acceptability and relevance, whether or not students witnessed bullying posttraining, and the use of the STAC strategies to intervene in bullying situations. Descriptive statistics were used to assess acceptability, relevance, and the use of STAC strategies. Linear regression analysis was used to assess the relationship of program acceptability and relevance to STAC strategy use. Results: Of the 229 student participants, the majority reported the program was acceptable (188, 82.1%, to 206, 90.0%) and relevant (180, 78.6%, to 190, 83.0%) for students at their school. Of the 54.6% (125/229) of students who witnessed bullying posttraining, 88.8% (111/125) reported the use of at least one STAC strategy to intervene when witnessing bullying. Students were most likely to use the STAC bystander intervention strategies Turning it Over and Accompanying Others, relative to Stealing the Show and Coaching Compassion. Regression analyses revealed that program relevance was a significant predictor of posttraining use of STAC strategies (P=.016). In contrast, program acceptability was not a significant predictor of posttraining STAC strategy use (P=.660). Conclusions: This study provides support for the acceptability and relevance of STAC-T and its effectiveness in promoting the use of the STAC strategies to intervene in bullying situations. Furthermore, program relevance was related to STAC strategy use, highlighting the importance of assessing program relevance for specific student populations.