@CTMom21 Yes, this is particularly true with boys. While I don’t remember it being a factor when I was in high school although that was long, long ago. In those days, many kids from high income families with boys who weren’t good academically had them do a PG year. This was particularly true if they were good in sports. There are few PG programs today.
Now, it seems that many high income families/families in some demographics hold their boys back esp. for sports reasons. Some kids are smaller than others, some are young in the calendar year etc. Among our extended family of boys, we have one who is a stellar athlete. He was held back around K or grade 1 ( mainly for sports reasons and young in the year). Has worked out for him. But maybe for the kid who is the true grade age, it might not be that great. It’s hard to play against someone who weighs 80lbs more than you and is effectively 2 years older as another member of my family learned the hard way.
I have noticed that there are fewer girls who repeat for sports reasons. Have seen a few come in to fill particular slots ( weak X team, bring in a few more girls). These kids are repeats. The rest are coming from private schools. It also depends on the school. The schools with less than 20% admit rates have pretty high academic levels of competence so that can mean repeats are more common with athletes. Seems even in the highest rated schools there’s a mix of kids with various talents. I haven’t run into any kids yet who are strong in the arts and are repeats. Seems the rules bend most for the athletes.
It’s interesting. And varied. Yes, some schools seem to double in size. Others vary by only a handful of students. Guess that they are all looking for different things.