Is it impossible, that the poor parents that choose to enter their kids into the program, are different from the poor parents that do not enter their kids? Or that the students that voluntary enter the program are more ambitions than the ones that do not enter?

One could at least try to cancel the effects of intelligence on the future income of the kids by giving them IQ-tests and grouping them according to their score. Surely the authors are not naive enough to believe that their program increases the intelligence of the young students??

My golly, the social study scientist keep making the same misstakes over and over again.. They just never learn, and have no interest in learning either.