From the Introduction: "A core mission of kindergarten through 12th grade (K-12) schools throughout the United States is to create safe and secure environments to help promote the achievement of schools' education objectives. Achieving this mission presents local education agencies with significant challenges, as they address a wide variety of threats ranging from weather-related natural hazards, to student fights in hallways, to violence involving the use of weapons. These and other types of school safety-related incidents are all significant cause for concern for local education agencies; they affect not just those involved, but the broader school community as well as members of the surrounding community. Notably, the reality that no two schools across the United States are identical further complicates the challenge of creating safe and secure environments that promote teaching and learning. [...] This guide demonstrates how taking a systems-based approach to layered security can help schools create safe and secure learning environments without requiring principals, assistant principals, facility managers, and other staff to become security experts. The purpose of the document is to provide guidance to local education agencies on how to plan for and implement this type of approach to school security. It is intended to steer planning for the broad range of K-12 schools that exist across the U.S. and is applicable across pre-Kindergarten and Kindergarten through 12th-grade grade levels, diverse geographical contexts ranging from rural to urban, and schools at various levels of maturity in their security planning process. The guide does not take an all-hazards approach to school safety and security, but focuses instead on the most common incidents of crime and violence that K-12 schools in the United States face today."
U.S. Cybersecurity & Infrastructure Security Agency: https://www.cisa.gov/