The expulsion hearings page is a great page that shows the legal side of expelling a student. A sample middle school discipline policy can be found here. This is a good example of a discipline policy for an actual middle school. Keeping schools safe is important. This link will take you to an article about the punishment for various offenses.
School discipline discusses the characteristics of negative behavior.
This ERIC article also explains how schools can help reduce this behavior. I believe that school expulsion is both good and not so good. I believe in zero tolerance, but I also believe in second chances. If an adolescent is heading in the wrong direction, steps need to be taken in order to get him or her straightened out. I do not feel expelling a student serves much purpose for our society as a whole.