Verbatim US Soccer's RAE rationalization for birth year change in 2017:
The focus moves away from bigger, faster, stronger
-Changing to birth year registration doesn’t eliminate relative age effect (RAE) because whenever there is a defined age range, someone will be the oldest and someone will be the youngest
-However, this change does help better understand and account for RAE
-Parents and coaches should have an increased awareness of a player’s birth month relative to his or her peer group and level of performance
-This should help combat focusing on kids that appear to be better simply because 6 they are up to 364 days older than a teammate or opponent
Now if any of you parents that had kids playing in 2017, particularly youngers, and you want to torture yourself, you can read below all of the "Player Development Initiatives", like BY, buildout line, small-sides, etc and the claimed benefits (aka BS). You can thank me later.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://static.ussdcc.com/users/148963/897090_eng-october2017pdi.pdf
While done with good intentions, the initiatives have done nothing to improve player development and the landscape has only gotten worse in the last 7 years.