This project assesses the effectiveness of a one-day, 5-hour workshop (ESSI training, hereafter) designed for joint instruction by school staff and police to all school staff. The goal was to promote positive outcomes and reduce police involvement in interactions between staff and students exhibiting inappropriate behavior through increased staff awareness of youth behavior, the functions of the juvenile justice system, and disproportionate minority contact (DMC) in disciplinary action. 1,024 school staff participated in 51 ESSI training sessions throughought the 2015/16 academic year, which also serves as the training year in the longitudinal data. Schools which did not participate in the training served as controls for the participating school. Data were drawn from a panel of students enrolled in either a training or control school, with ten schools in each group. Data on this panel of students was collected for a five-year period, from the 2013/14 through the 2017/18 academic years. School-level data serves as the unit of analysis, as the study's main goal was to test the effects of training on school-wide outcomes. The estimated coefficient indicates small attendance reductions during the post-training phase for the training group. This indicates that most of the differences between the training and control group were statistically insignificant and that there was no pattern of statistically significant positive effects across the training schools. The second set of analyses, performed on student-level data, indicates that male and minority students are more likely to be involved in disciplinary incidents and to receive suspensions or expulsions as a consequence of their behaviors than White and female students.