So far we have focused on preventing behaviors that are off-task, inappropriate, or annoying. Our advice has all
been pro-active or forward-looking: plan the classroom space thoughtfully, create reasonable procedures and rules,
pace lessons and activities appropriately, and communicate the importance of learning clearly. Although we
consider these ideas to be important, it would be naïve to imply they are enough to prevent all behavior problems.
For various reasons, students sometimes still do things that disrupt other students or interrupt the flow of
activities. At such moments the challenge is not about long-term planning but about making appropriate, but
prompt responses. Misbehaviors left alone can be contagious, a process educators sometimes call the ripple effect
(Kounin, 1970). Chatting between two students, for example, can gradually become chatting among six students;
rudeness by one can eventually become rudeness by several; and so on. Because of this tendency, delaying a
response to inappropriate behavior can make the job of getting students back on track harder than responding to it
as immediately as possible.