I think that that is the key right there... parental involvement is critical.From Motherbear:
Truthfully, I think any child whose parents are involved in his or her life is going to turn out ok. I know plenty of people who turned out just fine through public school. It's just not a route I'm willing to take with my kids.
The down-side to public schooling is the disparity in funding between districts and the fact that so many parents look at public schooling (K-12) as tax-payer provided daycare. They just don't get involved.
Regarding well-behaved kids...well, that takes you right back to the parenting issue again.
My son is now going into his Senior Year. Even when speaking to his former-Marine/Soldier Dad he refuses to cuss, despite being exposed to it constantly at school.