A reader wonders how to stop students from starting to leave class early, creating a cascading effect of rustling sounds that are distracting and that make the last few minutes of class difficult for teaching and learning.
I don't know if my method will work for everyone, but I do have a preferred approach to this problem for large classes. Others may have more effective strategies (feel free to share), but this one has worked very well for me:
On the first day of class, I go over the usual logistical stuff at the beginning of class, and then I start talking about the actual course material. Near the end of class, but not exactly at the end, I tell the class that I understand that many of them need to get to another class or to a job, and that it's a large campus so they need every minute possible. I say that I will make a deal with them. I will never go over the scheduled class time, and I will even end a minute or so early if they do not start getting ready to leave in advance of the end of class; i.e., when I have announced that we are done for the day.
I explain that the putting away of notebooks and laptops, the collecting of gear, and the zipping of backpacks adds up to considerable sound and distraction, that sometimes near the end of class I sum up the material in a way that might be helpful for reviewing/studying but this gets lost in the "rustle", and then I repeat that in return for their not preparing to leave early, I will make sure that we finish on time.
Then I talk for a few more minutes, and keep my promise on the very first day.
And it works. I don't know why, but it does. After that, I never have a problem. I may not have their full attention to the very end, but at least I have their quiet inattention.