Lucy C. Sorensen, et al., Annenberg Institute, Brown University.In this working paper, researchers use national school-level data to estimate the impacts of sworn law enforcement officer (SRO) presence in public schools. The study finds that SROs increase chronic absenteeism, particularly for students with disabilities, and intensify the use of suspensions, expulsions, police referrals, and arrests of students.These latter effects are consistently over two times larger for Black students than white students.