I'm taken aback by this whole discussion. For all the bashing that goes on in HN about schools being glorified test prep centers and not living up to their pote

I'm taken aback by this whole discussion. For all the bashing that goes on in HN about schools being glorified test prep centers and not living up to their potential for educating students, we sure are quick to accept "studies" like this that use test scores as an indicator of intrinsic worth of the educational system in a country.