Methods. The study sample includes all students in 24 middle schools in a large urban district. Schools were assigned to receive SPS or not using a matched pair randomized design. Data for the study come from administrative school records. To address our primary research questions, we used OLS regression analysis with student data aggregated to the school level. All models included dummy variables for each of the matched pairs and the prior year’s score of the outcome. Our primary outcomes included the proportion and severity of all incidents and of incidents in public spaces, suspension rates from incidents overall and in public spaces, and student reports of safety and adult support based on the district’s annual school climate survey. To address our exploratory research questions, we used two-level hierarchical modeling with students (L1) nested in schools (L2). All models included dummy variables for the matched pairs and student demographic covariates. Our exploratory outcomes included number of suspensions and days suspended, attendance rate, math and ELA scale scores.
Results. To date, the proportion of incidents and the suspension rates overall and in public spaces was not significantly different in SPS schools compared to control schools (E.S. = 0.05-0.14). However, moderate effect sizes of 0.41 for incident level overall and of 0.48 for incident level in public spaces indicate a trend towards lower average incident severity in SPS schools compared to control schools. There was no significant impact of SPS on student-reported safety and adult support (E.S. = 0.02-0.04). A trend-level (p < .1) negative effect of SPS on number of days suspended (E.S. = 0.08) is consistent with the finding that SPSS is reducing the severity of incidents. There was a trend-level positive effect of SPS on student math test scores (E.S. = 0.06). There was no significant treatment effect on ELA test scores, attendance, or number of suspensions (E.S. = 0.01-0.04).
Conclusion. Impacts after one year of implementation show some promise that the intervention is increasing school safety by reducing the severity of disciplinary incidents. Effects on school climate and number of disciplinary incidents, as well as suspension rates, may not be visible until the second year of implementation.