Many schools and school districts have taken measures to address this pressing concern of.
Should colleges have clasroom doors that lock.
The vast majority of school doors can remain locked from the outside while still having a handle release on the inside mainly due to building or fire codes.
See figure b with this function teachers do not have to enter the hallway to lock the classroom door.
See figure a in response to school shooting concerns a new function was designed called a classroom security function door locks with this function can change their locked or unlocked status on both the outside or inside of the classroom but still only through the use of a key.
Many doors that do not have hardware that allows teachers to lock it from inside the classroom can be locked by turning a thumb turn or by pushing a button on the door.
However if a school has doors that have deadbolts or similar locks there are situations where a locked door can for example prevent egress in an emergency.
Some schools prefer doors that students can lock in an emergency.
Even though the school district has updated classroom doors to classroom security locks which can be locked from the inside with a key the outside levers will be kept locked.