Nope... the criticism on nonrandomness centered on the fear that preschool teachers would treat the children with low IQ with more attention and that the control group had a couple more low IQ students and that there were 5 who did not complete the study - one kid died and four others moved away - so that the test group wound with a couple students less than the control group.

But researchers say that the study is on preschool education and not on special education. Low IQ kids got equal treatment. Researchers say there is less than 5% difference  between test group vice the control group. Keolu is lying when he claims that differences ("nonrandomness") invalidate the outcomes. 

Point is that other studies have agreed in their findings over the past 60 years. There is universal agreement on the benefit of preschool.