Rob:
I mean no disrespect, but the issue is the ENTIRE ATTENDANCE area from which private schools can draw�not the school size.
The reason we have A, AA, AAA, AAA is to correct for the draw WITHIN a school.
Again, there is research that private schools have advantages due to the ATTENDANCE area discrepancy, along with the inherent affluence advantage found in most private settings.
The research, which I have posted before:
http://ohiosportsgeography.tadherold.com/hsfoot/publicprivatesxyears/publicprivate.htm