<p>I didn’t see where they separated optional/discretionary redshirting – the kind where a parent decides to hold back a high- or medium-achieving child – from redshirting done for “cause” or a perceived need due to a child underperforming with children the same age.</p>
<p>So, with these two groups commingled, it seems almost axiomatic that children who were held back do not perform as well as those who weren’t. I’m not sure that it follows from these populations that we can say that being younger pays off. The younger kids who were not held back might simply have been doing well to begin with. Reduce their numbers by kids who were not thriving in that class year and, guess what? The group that remains in that class will do well. Add to their numbers the children who are a year older who weren’t doing well with their age cohorts and, voila!, they get instantly brighter – all without learning a damn thing to boot! Maybe I missed the part where they account for this dynamic or maybe they did and just didn’t bother to tell us. If not, then I’d say that this is flawed.</p>