" The percentage of public schools reporting the presence of security staff was higher during the 2015–16 school year than during the 2005–06 school year (57 vs. 42 percent). The percentage of schools reporting the presence of sworn law enforcement officers was also higher in 2015–16 than in 2005–06 (48 vs. 36 percent), as was the percentage of schools reporting the presence of a School Resource Officer (42 vs. 32 percent; Spotlight 1).
" Among secondary schools with any sworn law enforcement officer present at least once a week, a lower percentage of schools in cities reported having an officer who carried a firearm (87 percent) compared with schools in towns (97 percent) and schools in suburban and rural areas (95 percent each; Spotlight 1).
" Among public schools with any sworn law enforcement officers, a lower percentage of primary schools (51 percent) than of secondary schools (70 percent) reported their school or district had any formalized policies or written documents (such as a Memorandum of Use or Memorandum of Agreement) that outlined the roles, responsibilities, and expectations of sworn law enforcement officers at school (Spotlight 1)."
Musu-Gillette, L., Zhang, A., Wang, K., Zhang, J., Kemp, J., Diliberti, M., and Oudekerk, B.A. (2018). Indicators of School Crime and Safety: 2017 (NCES 2018-036/NCJ 251413). National Center for Education Statistics, U.S. Department of Education, and Bureau of Justice Statistics, Office of Justice Programs, U.S. Department of Justice. Washington, DC.