That said, I wonder about some factors in this study... were the children who were sent to school despite just making the cutoff more likely to be smart or mature already? Or, were those who were held back those who suffered even a year later from not being well suited for the sit and drill classroom?
Our state does testing of school readiness skills for literacy early in kindergarten. I'd love to see a study looking at the readiness by age to test for this exact effect.
My DD was 3rd youngest of 120 kids in her grade at her elementary school. Assuming no redshirting, there should have been 15-20 younger than her. Any time there was even the slightest problem, it was pinned on her age.
