Tracking. Anecdontes are not the most reliable of data, but they are data.
My sister n law is a professor at a local Community College. Much of her class load is remedial work. Her students, by a very large margin, tell her they would lvoe, purely love for tracking to be reinstated once they find out what it is and can do.
This is another reason why Home Schooling is so popular. yes, much of the motivation, most of teh motivation is not very thinlyt disguised White Flight, but not all of it.
I have a brother whose kids are home schooled. Very smart kids, both of them (of course they are, I'm their Aunt by blood!) the amount of work my sister-in-law puts into their education is phenomenal. But they have an advantage many Home Schooled kids do not. One of their uncles and one of their aunts are teachers, their curriculum gets a once-over by those relatives. And by the history-nerdette of yours truly.
My brother told me once he could tell that a history textbook didn't pass muster with me, I didn't have to say a word, just the way my eyes went wide and I hyperventilated as I skimmed it were enough. I had gone straight to the section on the Antebellum South in the USA, a sure litmus test for the tone of such a book, I have found.
It was truly atrocious. Went on at some length abut the bond of Christian faith that linked and moderated the relationship between black slaves and white masters, the mutual respect that arose from that.
It was vile. Evil is not too strong a word.
And it came highly recommended by a Home Schooling association. Which is why I have such deep reservations for Home Schooling, so many parents don't have access to, or trust in the "subject matter experts" the way the parents of my nephew and niece have.
The kids' assessment scores are splendid, by the way. Of course they are. My brother is (almost) as smart as I am.