When parents say that their children are in a good school district it almost always means that the parents are doing a ton of afterschooling, private tutoring, or study clubs. The parents and kids do all the work outside of school and the school is quick to claim the credit.
Of course, if the kids aren't getting tons of afterschooling their standardized test scores show it and the school blames the parent.
Gee! Win win for the schools. Good standardized test scores: School takes credit. Bad standardized test scores. Blame the parent.