I don’t doubt that private schools teacher have students that score better than public school students (we can argue the weight of all the factors later) and I don’t think GP is doubting that.
His doubt is that private teachers that are paid less than public school teachers provide better results. To prove the original assertion you need to include the income levels of these private school teachers and graph them against the performance and income level of the public school teachers.
His doubt is that private teachers that are paid less than public school teachers provide better results. To prove the original assertion you need to include the income levels of these private school teachers and graph them against the performance and income level of the public school teachers.