Impact of School Police Reform on Student Safety and School Experiences, California, 2017-2022 (ICPSR 39454)
Version Date: Jul 16, 2026 View help for published
Principal Investigator(s): View help for Principal Investigator(s)
Trevor A. Fronius, WestEd
https://doi.org/10.3886/ICPSR39454.v1
Version V1
Summary View help for Summary
This study examined the impact of policy changes resulting in the removal of school police on student outcomes. The study took advantage of recent widespread school police policy changes in California and extant survey and administrative data, and used a quasi-experimental study to compare school districts that removed school police during 2019-20 or 2020-21 with a matched comparison group of districts that did not remove school police. The study examined the impact of such policies on middle and high school students' reported safety, behavior, and well-being as well as administrative disciplinary data (suspensions).
This study also examined whether school police policy changes had differential impacts depending on the level of schools' mental health supports (student-to-counselor ratio). Finally, researchers conducted interviews with a sample of administrators and partnering community-based providers to identify the reasons for, and impact of, removing or retaining school police as well as policies and practices implemented as alternatives. There are no impact studies, to the researchers' knowledge, that examined the impact of removing school police. This study's findings are critical to understanding how the presence of police in schools relate to student outcomes.
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District
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Access to these data is restricted. Users interested in obtaining these data must complete a Restricted Data Use Agreement, specify the reasons for the request, and obtain IRB approval or notice of exemption for their research.
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Study Purpose View help for Study Purpose
The purpose of this study was to document and disseminate rigorous research on the impact of school police reform on student safety, behavior, and well-being. The goal of the study was to fill a critical gap in the current empirical literature on school police as documented by National Institute of Justice's (NIJ) 2022 report to Congress on school policing programs, specifically the recommendation that "funded research should focus on better understanding what impacts the removal of police from schools might have on students, schools, and communities at large."
The study had four objectives. The first objective was to document school police policy changes across the top 100 school districts in California by school enrollment. The second objective was to apply rigorous quasi-experimental methods to evaluate the impact of school police policy changes resulting in the removal of school police on student safety, behavior, and well-being and disciplinary outcomes. The third objective was to contextualize the findings through a purposeful sampling of school district and police leadership to document the reasons for local policy changes related to school police and the perceived impact of the reform on the school district community. The fourth and final objective was to disseminate the findings from the study to a broad set of stakeholders through several mediums (e.g., webinars, briefs, blogs, journals, conferences) to ensure findings are useful and accessible to professional and academic audiences.
Study Design View help for Study Design
This study included an impact study and an implementation study. The impact study applied quasi-experimental techniques to assess the effects of school police policy changes, focusing on student safety, behavior, well-being, and discipline. The qualitative implementation study supplemented the impact study, using a case study approach within two districts that differed in their implementation of policy changes resulting in police removal from schools.
Impact and Exploratory Study
Researchers sampled the top 100 school districts in California, based on student enrollment, and limited the sample to traditional grades 6/7-8 middle schools and grades 9-12 high schools. The top 100 districts in the state represented over 50 percent of the total student enrollment in the state and allowed the research team to focus on a similar initial sample of school districts. The sample was limited to traditional middle and high schools given the prevalence of student safety and disciplinary incidents and presence of school police are greatest among these schools relative to elementary schools. Within this initial sample, WestEd matched schools where district school police policy changes resulted in removing school police with schools in districts where school police were not removed based on school and student characteristics using Euclidean distance matching. The quasi-experimental design (QED) examined changes in student outcomes between the baseline 2018-19 and 2021-22 school years.
The research team utilized a list compiled by Education Week to identify school districts that ended their contracts with school police officers or disbanded their own police department during the 2019-20 or 2020-21 school years. They then conducted an environmental scan and combed through news articles and district websites as well as called and emailed school and district staff to finalize the treatment and comparison groups. This resulted in seven treatment districts, 79 potential comparison districts, and eight districts that were excluded from the study. The eight school districts were removed from the study because:
(a) the school districts removed school police but then restored them during study's time period (i.e., the 2019-20, 2020-21, and 2021-22 school years);
(b) Los Angeles Unified School District and San Diego Unified School District were excluded from the study because, as the two largest districts in California, they are anomalies and would be difficult to find matched comparison schools for outside of these districts; or
(c) the school district never implemented school police.
Using this initial list of school districts to potentially include in the study, the study team worked to identify the study's sample of schools. The two inclusion criteria were, schools were traditional middle or high schools, and the schools had school enrollment and outcome data from the baseline and outcome years. As a result, 394 schools (60 treatment schools from 6 treatment districts and 334 potential comparison schools from 40 districts) were included in matching process.
Implementation Study
The implementation study employed interviews to gather examples from the field and insights into the districts' experiences following policy decisions regarding school police. To select districts to interview, WestEd calculated for each of the treatment and comparison schools their average change scores for each of the impact study's outcomes. Then for each of the outcome measures, WestEd identified the top five schools with the largest change scores in the favorable direction (e.g., biggest decreases in violence victimization) and the top five schools with the largest change scores in the adverse direction (e.g., biggest decreases in caring staff-student relationships). WestEd identified an initial set of treatment and comparison districts with schools that demonstrated both favorable and adverse changes as the initial group of districts to conduct outreach for the interviews. This sampling approach ensured that selection of treatment and comparison districts for the implementation study was not biased.
From fall 2024 to winter 2025, WestEd reached out to school and district staff from treatment and comparison districts via email and phone calls to invite their participation in interviews. WestEd identified these staff by searching district websites for staff who worked in the areas of school safety, student discipline, restorative justice, and student support services. The virtual interviews ranged from 30 to 60 minutes and were conducted between October 2024 to February 2025. At the end of each interview, WestEd asked the interviewee if they had any recommendations for additional district staff who could potentially speak about the study's topic areas.
Sample View help for Sample
The quasi-experimental design study sampled from the top 100 school districts across California, by student enrollment, and limited the school sample to traditional grades 6-8 middle schools and 9-12 high schools. For the implementation study, the research team contacted district staff from five school districts (2 treatment districts and 3 comparison districts). After multiple outreach attempts, staff from two school districts (one treatment and one comparison district) agreed to participate in interviews. The final interview sample included two comparison district staff and six treatment district staff.
Time Method View help for Time Method
Universe View help for Universe
District and school administrators and high school students in California
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Description of Variables View help for Description of Variables
The study is a combination of public and restricted release, which included both qualitative and quantitative data.
DS1 is the quantitative data that will be released publicly, and contained 15 variables with numeric responses. DS1 included descriptive variables such as whether schools retained or removed school police, the baseline of percentages of students suspended from in the year 2018-2019, school stability rate, and the baseline percentage of African Americans in schools between 2018-2019. Additionally, there were no demographic variables in the dataset.
The Interview Data (DS2) was observer notes with direct quotes from participants.
Presence of Common Scales View help for Presence of Common Scales
The study used the California School Climate, Health, and Learning Surveys' (CalSCHLS) California Healthy Kids Survey (CHKS) to examine the following constructs:
Original Release Date View help for Original Release Date
2026-07-16
Version History View help for Version History
2026-07-16 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:
- Checked for undocumented or out-of-range codes.
Notes
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This dataset is maintained and distributed by the National Archive of Criminal Justice Data (NACJD), the criminal justice archive within ICPSR. NACJD is primarily sponsored by three agencies within the U.S. Department of Justice: the Bureau of Justice Statistics, the National Institute of Justice, and the Office of Juvenile Justice and Delinquency Prevention.