I'd be curious what you define as "variable costs". Clearly building costs, materials, etc. wouldn't be in that bucket. What about teachers?
What is and is not a variable cost would be determined according to cost management accounting principles. Presumably, teachers would be classified as a variable cost since a school with 500 kids likely doesn't need as many teachers as a school with 800 kids.
The statistic that most strongly correlates to student success (outside of socio-economic status) is class size.
That depends on who you ask.
I'm not defending under-performing public schools. Clearly we need to fix that but I also believe that's a function of the socio-economic status of the students (and quality of the parents by proxy). Removing funding from public schools may help the individual student moving to the charter school but dooms the nonperforming school to becoming a prison. Of course, some might argue they are already there.
You don't defend underperforming schools, but you give credence to their self-serving premise that a lack of money is what holds them back. I don't buy it, because most of them don't actually lack money and because most of them get outperformed by schools that get a lot less money.
We have a different set of priorities. You want to keep the bad school from becoming a prison. My priority is to give the kids a chance to get out of the prison or alleged prison. If we can give them a chance to get a good education and don't offer it because we're trying to ensure that their failing school never has to compete for money, that's an injustice.
I agree with you that bad parenting is the biggest problem. Schools in Detroit don't get bad results because something is wrong with the schools (though something is wrong). They get bad results because something is wrong with the families of the kids. So long as it's socially acceptable for large numbers of men to have sex, make babies, and then shirk their responsibility to become real husbands and fathers, we're going to have large numbers of failing kids. It's a social and moral problem, not a school problem.
However, not all the families are a mess. Some of those kids have responsibile dads. Some of them have single moms who work 2 or 3 jobs with hopes that their kids will do better. Letting them have that chance should be our top priority and shouldn't be contingent on the public school reforming itself.
