The DESE just published school discipline statistics for last year. I find it interesting that 25 of the top 30, in terms of most students suspended out of school, are charter schools. And the top 17 are all charters -- you can check it out by going to the chart (http://profiles.doe.mass.edu/state_report/ssdr.aspx) and sort by percentage of out-of-school suspensions.
It's frequently said that charter schools have ways of causing students with disruptive behaviors to leave, and I have personally experienced a couple of examples of this. Some years ago, the head of a charter school consulted me about a particular discipline issue. I gave him my advice, and a couple weeks later, asked him how it had worked out. He said, "Oh, we just told the parents that we wouldn't pursue it further if they withdrew him and returned him to the regular public schools."
It appears that more frequent use of out-of-school suspensions may also lead to the same result. Of course, excluding students with difficult behaviors is one of the reasons charter schools are so popular with parents. And it's difficult to know exactly how to hold charter schools accountable in this area -- if a child is disruptive, and frequently suspended, and parents return him/her to the regular public schools, probably also requesting an evaluation for special needs, that appears to just be parent choice. In order to have a level playing field, though, the child would have to be required to stay at the charter, and the charter assume the expense of special services if that's what's needed. But that flies in the face of the concept of parent choice. . .