The crazier, more-expensive, and more-difficult the method is, the more improvement it should show; craziness should filter out less-committed parents.
I think there’d be a U-shaped curve. Requiring some degree of effort will select for people who are willing to make good choices. At some point, craziness and expense will swamp out the good effects.
I have an example from food rather than schooling—vegetarians might be healthier than the average person. Vegans might not be, and it’s even less likely for fruitarians. Breathairians certainly won’t be healthier than average.
I think there’d be a U-shaped curve. Requiring some degree of effort will select for people who are willing to make good choices. At some point, craziness and expense will swamp out the good effects.
I have an example from food rather than schooling—vegetarians might be healthier than the average person. Vegans might not be, and it’s even less likely for fruitarians. Breathairians certainly won’t be healthier than average.