Until a few minutes ago I had never heard of "redshirting" although I was familiar with the concept. Some parents want to hold their children back from kindergarten (or have them repeat kindergarten) so they will be older and more mature than the other students in their class. A school teacher advised us to do that for one of our children but we adamantly refused. Best decision we ever made concerning the education of our children.
When I was growing up the best and brightest students were allowed to skip a grade if they were doing well. (I took grades three and four in a single year.) It was a mark of achievement to be among the youngest in your class, especially if you were doing as well, or better, than the other students. On the other hand, if you were the oldest in the class then your achievements were discounted because you had an intrinsic advantage.
When I was growing up it would have been psychologically devastating to be the oldest student in the class and not be at the top of the class academically. (That's partly because the oldest students were usually the ones who had flunked a grade.) I wonder if parents who hold their children back have ever thought about the potential negative consequences? What happens if your child is just average and redshirting doesn't work?
Here's a 60 Minutes segment on redshirting. It features two people from the University of Toronto: writer Malcolm Gladwell (B.A. 1984, Trinity College) and economist Elizabeth Dhuey a professor in the Department of Management.