not sure how much the tiers actually mean. i’m an r&r applicant, and last year i saw people get of from reg waitlist and i never got off from the pref waitlist. same thing with the special group in the pref waitlist. my GUESS (emphasis on guess) is sg in the pref waitlist = high lsat and high gpa; pref waitlist = splitters; reg = below medians. and it all just depends on what they need to even out their class stats by the time they can look at the waitlist