This paper examines whether compulsory metal detectors affect daily high school attendance and whether these effects differ across school socioeconomic contexts. Using administrative daily attendance data from six Salem-Keizer high schools during the 2024-2025 academic year, I estimated fixed effects models that exploit the districts staggered rollout of metal detectors. The results suggest that metal detector implementation is associated with a modest decline in attendance. In the preferred specification, metal detectors are associated with a 0.7 percentage point decrease in daily attendance. The heterogeneity analysis shows that the estimated effect for non-Title I schools is small and insignificant, while Title I schools experience a 1.3 percentage point decline in daily attendance when metal detectors are introduced. These findings suggest that visible school security policies may shape students’ engagement and outcomes in ways that extend beyond their intended safety goals and that these effects are unevenly distributed across school contexts.
