From the Quick-Start Guide: "This Quick-Start Guide is intended to help users of the K-12 School Security Assessment Tool (SSAT) use the tool and interpret the results. Security and safety planning is a continuous process. Consider using the SSAT regularly, or whenever your school experiences substantial changes in relevant threats or in safety or security plans or capabilities. More information about the SSAT structure and limitations can be found in the accompanying User Guide and Technical Appendix. [...] The SSAT will help you identify the physical security assets already in place at your school, and the gaps in your physical security system. The results that it provides are actionable, relevant to your school's context, consider cost implications as well as the impact that security measures may have on school climate, and aim to increase the overall security benefits of your school's entire physical security system."
U.S. Cybersecurity & Infrastructure Security Agency: https://www.cisa.gov/