My son is in 2nd grade and my daughter started 0 grade (=1st grade in other countries), both at the local public school. Socially it is excellent - walkable, easy to make play dates...Academically it is poor (bottom 3rd). We were willing to forgo the high education because of the social elements. This is ok for my sons class.
However, due to extreme budget cuts, my daughters class is totally unacceptable. Kids having to be restrained, taken out of class 5-10 times a day, jumping out windows, ripping stuff off the walls, biting, hitting, constant interruptions, telling the teacher to f*** off... And this was all just in one day when I sat in on the class for 3 hours. Socially they can not do anything either, because several kids in the class "can not handle" a play date. So the whole class is being pulled way down. And there is no learning, at all. And I mean none, no reading, no math, nothing.
We tried different things - asking to have her switched to the other class, which is a bit better. No. Asking for the 3 problem kids to be given the services and support they really need, so the other 22 kids can learn. No. Asking to pull her up a grade. No. Complaint to school board. They are "aware and working on it." But nothing has changed.
This is the class she is supposed to be in for the next 9 years. Over my dead body. We have put her on the waiting lists at the local private schools. There is one in particular that is perfect for her - the challenges really fit her personality.
Now the problem - My daughter loves her school - she has made many friends, gets to see her brother during the long recess and after-school program. But this is not good for her, not in the long run. And I have to look at the next 9 years, not just the next 6 months. How do I approach her, so she is positive about it? So she is not losing her friends, but going to make new ones? How do I say she will get the academics she needs, that it is a better school for her (without implying that the current school our DS will still be at is a "worse" school?) I have not told her yet, waiting for private school confirmation. But I really want her to start on a positive note, and both DH and I are afraid she will be furious with us for moving her "away from her friends."
I think it's easy to make the case: I can't imagine she doesn't understand the problem. Each kid deserves to learn in an environment appropriate to the child. This new school will provide her with the right environment. You are identifying the right class for her to be in so that she can learn and grow. Your son is already in a class that's a good fit. It's the class that's the problem, not the broader school.
Make a plan with her to maintain her friendships. Sit down and even consider making a contract on number of playdates, etc.
Support your child if she is having any problem. New school will definitely help, but you too take care that she should be comfortable there. Also talk ti her about new school so that she will feel excited about it.