That creates a market for lemons.
replyHow does a parent (especially one that is illiterate) compare between educational opportunities for their kids?
The status quo says that the schools do not measure outcomes (and when they do, they do not publish it, or publish it on a long delay), so any objective data parents could use is not available.
As opposed to the current market for education?
replyParents know which schools are good and which aren't. They are intrinsically interested in their child's education in a way that no one else is. It's an obvious solution.