We had a counselor a number of years ago who had a really good strategy for helping students decide whether to report a behavior. He called it the 3 Ds. The students needed to ask themselves whether the behavior is Dangerous, Destructive, or Disturbing. If so, it should be reported to an adult.
I still use this in my classroom today. I teach it to the students at the beginning of the year. We discuss what each of the terms mean and then go over examples and non-examples. For instance, if a student is going to tell me that he saw someone using pen when they are supposed to use pencil, that would be a non-example. We discuss together why that’s not really dangerous, disturbing or destructive. On the other hand, if they see a student hurting another student, that would be appropriate to report.
I also talk to them about the fact that we are a team and we help each other. Therefore, they need to report anything that does fit the 3 Ds. Otherwise, someone or something could get hurt or damaged, and since we work together, we don’t want that. I make a point of dealing with any behavior that is reported. This builds trust in the students and they are more willing to report problem behavior in the future.
Between building a family kind of feeling and teaching them explicitly what should be reported, the students have a clear expectation that if they report something, it will be addressed. I often ask students if they believe that I will deal with it, and they always say yes, they believe it. That’s the real key, is following through after something has been reported. Sometimes, it takes as little as a quick conversation with the other student (often they don’t realize they shouldn’t do whatever it was). Sometimes it make require a phone call home. Either way, the students can rest assured that it has been dealt with.
This has worked wonders with my students. I get very little tattling, but they are clear that I want to hear about things that fit the 3 Ds.