Are high ranking schools helding back kids from being promoted just to show good test scores?

In our area, the high-ranking schools encourage people to send their kids on time, but everybody (including me!) wants their child at the top of the class. SO almost all boys with summer birthdays are held back, and I'd say half of the girls. Heck, I even know a gifted girl with a late May birthday who was kept back!

The upshot is that part of the reason these schools look better is that their students are three months olders than the students in the next district over. And another huge part is that the parents in this district are overwhelmingly involved-- up to the point where each class has not one, not two, but THREE room mothers!

And a third big part (which no one seems to realize) is that the "better" schools, at least around here, spend LESS on curriculums, programs, interventions packages, etc., and put their money into experienced teachers. Our school doesn't serve breakfast, doesn't have preschool, doesn't have tutors, doesn't have motivational speeches. The annual science assembly is done by the high school science club, not an expensive hired dude. But-- in the five years since we've been here, they haven't hired a single rookie teacher. At our previous school in another state, almost every new hire was straight out of college-- and most didn't have a clue how to mange 20-25 antsy kids.