School Discipline and the School-to-Prison Pipeline: What Research Shows

School discipline practices have significant consequences for student educational outcomes, and research over the past two decades has documented both the scale of exclusionary discipline in American schools and its differential impact on students of color, students with disabilities, and students who identify as LGBTQ. The term school-to-prison pipeline describes the observed pattern in which exclusionary discipline, by removing students from educational settings and sometimes involving law enforcement, increases their likelihood of contact with the criminal justice system. Understanding the evidence on this pattern and on more effective alternatives is essential for school discipline reform. Suspension and expulsion rates in American schools are high by international standards. Data collected by the Department of Education's Office for Civil Rights document that Black students are suspended at rates approximately three times higher than white students, a disparity that holds even after controlling for behavior and income. Students with disabilities are suspended at higher rates than students without disabilities. These disparities have been documented consistently across decades of data collection and across different states, districts, and schools, suggesting they reflect systemic patterns rather than random variation. Research on the consequences of exclusionary discipline finds consistent negative effects on educational outcomes. Students who are suspended miss instructional time that cannot fully be recovered, fall behind academically, and are more likely to disengage from school. Longitudinal studies find that school suspension is associated with increased likelihood of dropping out, decreased likelihood of college attendance, and increased likelihood of involvement in the criminal justice system. A single suspension doubles the probability of juvenile justice contact in some studies. Zero-tolerance policies, which mandate specific punishments for certain infractions regardless of context, were widely adopted in the 1990s and have been associated with dramatic increases in exclusionary discipline without evidence of corresponding improvements in school safety. Research on zero-tolerance policies finds that they remove context and discretion from discipline decisions in ways that produce disproportionately harsh consequences for minor infractions and that they disproportionately affect students from marginalized groups. The American Psychological Association's review of zero-tolerance research concluded that the evidence does not support zero-tolerance as an effective school safety strategy. School resource officers, uniformed law enforcement officers placed in schools, have increased significantly since the 1990s. Their presence has been associated in some research with increased juvenile justice referrals for behavior that would previously have been handled administratively. A study using school shooting data found that SROs did not reduce the incidence of school shootings, which are the events most commonly cited to justify their presence, while other research documents increased arrest rates in schools with officers. The evidence on SRO effects is mixed and context-dependent, and debates about their role in schools have intensified following high-profile school shootings and following documented incidents of inappropriate use of force against students. Restorative practices, which focus on repairing harm, rebuilding relationships, and addressing the root causes of misbehavior rather than punishing and excluding students, have accumulated a growing evidence base as alternatives to exclusionary discipline. Restorative circles, conferences, and other practices provide structured processes for students, affected parties, and community members to address harm collaboratively. Research on restorative practices in schools finds reductions in suspension rates, improvements in school climate, and in some studies improvements in academic outcomes. Implementation quality varies significantly, and restorative practices produce better results when they are part of a comprehensive approach rather than isolated programs. Positive behavioral interventions and supports, a framework for defining, teaching, and reinforcing expected behaviors at the whole-school, classroom, and individual levels, has substantial research support for improving school climate and reducing behavioral problems without relying on exclusionary discipline. PBIS uses data to identify students who need additional support and provides tiered interventions matched to need. Multiple randomized trials and quasi-experimental studies have found positive effects on behavior, discipline rates, and academic outcomes. Trauma-informed approaches to school discipline recognize that many behavior problems are manifestations of trauma responses, and that punitive responses to trauma-related behavior worsen rather than improve students' ability to regulate their behavior. Schools that implement trauma-informed practices create safer environments for all students, reduce the frequency of discipline incidents, and improve outcomes for the most challenging students. These approaches require professional development for all staff and shifts in school culture that take sustained commitment to achieve.