Most older classroom doors were designed with the lock cylinder on the corridor side, a deliberate choice meant to prevent students from locking teachers out. The tradeoff is significant: during an emergency lockdown, a teacher must open the door, step into the hallway, turn a key from the outside, and get back inside. A teacher without a key cannot lock the door, and students alone in a classroom have no way to secure themselves.
The common workaround of leaving the door unlatched for easy access throughout the day creates a problem: an unlocked classroom door is accessible to anyone, and locking it during an emergency still requires hallway exposure.
According to the National Center for Education Statistics, 1 in 4 public schools in the United States lack classroom doors that can be locked from the inside. TeacherLock addresses this directly. The door stays closed. The teacher stays inside. No key required, no hallway entry.
