what does this tier system mean? does it matter?

People arent "hell-bent" on it. It's literally only GDIs who care about ranking. Once you go through rush or recruitment and find your home, you will realize that literally NO ONE in the greek system cares about rankings. You will make friends in every chapter regardless of their ranking. It doesnt matter in uni or beyond. Go through recruitment with an open mind because "top house" means nothing.

For sororities, it just refers to which chapters have the best numbers during recruitment. There are a lot of things that go into recruitment numbers, such as international rules, how much training a sorority does that year, and superficial things like their recruitment video, room decor etc. Basically which chapter can make the most girls want to get invited back to their room during recruitment means they'll have higher numbers - it's pretty fake.

It's not an indication of your experience in that chapter the other 11 months of the year, nor is it the be-all, end-all. Chapters can be strong in recruitment and have a rocky sisterhood. That's why it's important to not think about tiers and go to the place you really connect with. Tiers are meaningless. No one in the Greek system actually cares about them with the exception of maybe first years.

It can also refer to how well a sorority does throughout the year too though. For example, do they have high attendance at other chapters' philanthropy events, do they have a lot of women involved in Panhel or outside of the Greek system in leadership roles, do they have good retention rates (i.e. do not a lot of girls drop out from the chapter), do frats want to have exchanges with them (which SEEMS really superficial and backwards, I know, but good frat relations = higher turnouts at your sorority's events and philanthropy and you also just get to make more friends).

TL;DR - It doesn't matter after graduation but being in a mid-top tier sorority can mean having a MARGINALLY better sorority experience. Sisterhood, memories, and a place to call home and make your best friend will happen no matter the chapter

it literally just means who has more attractive people / athletes that year, and how popular are their events.. ^^^ you can listen to that jazz all you want but this is the truth.