We organized for about 3 months prior to the drill. We participated last year and it helps to have a state wide drill. All the employees know where we meet. We have emergency planning days where they can purchase supplies and things for their homes and cars at a discount. We have CPR and emergency training classes that people volunteer for about a month before the event. We break people up into teams that they are familiar with and interact with regularly so that they account for everyone quickly. We line people up and have them discuss where everyone is in their group. They check in with an incident command leader and then we clear them to go back into the building. The whole thing took about 15 minutes for 160 employees between 4 buildings. Quick and painless and we all know it would be different in the event of a real quake but at least they know the steps and procedures.