Why would RAE be worse under BY vs SY? Or what was the reason that the study stated for the difference? I thought MLS Next was going to solve RAE with Bio Banding?
I think you just have to look at the actual rosters and see when the kids are born - and yes, I've looked at rosters based on date as I wasn't convinced, and it was pretty much on the money, with many rosters being higher than 80%. There are books that have been written on the RAE, across many sports, and the data is conclusive that kids born in the first half of the year make up 80% or more of the players. Conversely, the kids in the 20% achieve the highest level at a higher rate, something like 70% of them versus a smaller % of the "older" kids. Basically, that's because the younger kids had to be that much better to even get on the team.
Its not a US phenomenon only, btw, but recognized in other countries also, hence the bio banding initiative which obviously fell pretty flat here.
Its a pretty big deal though as the rosters are weighted to the Jan-Jun dates and now those kids would be competing with older kids for spots for the first time ... that will certainly put the cat among the pigeons. As soon as those parents realize, if this gets announced, they are going to lose their shit.
Fwiw, for the Aug-Dec kids, its a complete cluster for college recruitment. They play with Juniors who are being recruited in their Sophomore year - U17, and then in their most pivotal year, Junior, are competing with Seniors (Aug-Jul) for spots on their team, along with the regular Jan-Jul kids, as its now U19 (U18 vanished with the BY switch).