<p>The study–at least as reported in the magazine–does not seem to account for students who were redshirted by parents for developmental reasons that might well still be affecting their academic progress in high school. Same is true for the other cohort–younger kids are often sent to school because their parents recognize that they are ready for school, even if on the young side. So I’d say that blaming the lower achievement levels of the older students on the fact that they were redshirted is simply a case of faulty causation.</p>