Are you in the US? If so, it's probably permission for them to do a Functional Behavior Assessment. This is a document that tries to analyze what the "function" of misbehavior at school is. Personally, I think it's kind of stupid, because I don't think that most kids are connivers who have some kind of master plan that they are manipulating us with to get what they want. I think they just can't keep themselves together. Figuring out what skills they might lack and teaching those is useful, but I don't think an FBA really sets up the framework correctly to identify missing skills, instead of blaming the kid for trying to manipulate the adults.

That said, FBA is the language that's in the federal rules, so that's what they request and why. You have to sign before they can do it.