Prevention involves noting warning signs, taking threats seriously, encouraging student reporting, and following up on rumors. Physical safeguards include limiting access by locking all gates that cannot be monitored by staff, requiring visitors to check in at the office, issuing highly visible identification to be worn by visitors at all times while on campus, instituting dress codes or uniforms to permit easier identification of non-students, assigning a particular person or persons to monitor hallways and campus perimeter, and having staff make immediate contact with any person on campus who has not checked in at the office. There should also be a security inspection of the exterior and interior of the campus. Regarding a planned response, every school should have a safety plan that covers all possible catastrophes and disasters, including gun violence on campus. Some fundamental steps that all schools can take when planning a response to gun violence include installing an audible warning system, practicing student response to gunfire, defining teacher and staff roles, and developing a plan and practicing it. Teaching gun violence prevention and reaction skills to students should be done in a manner that increases students' confidence in the school staff's abilities to reduce the chances of violence or initiate a safe response in case of a rare gun attack on campus.