My niece and 4 other rec girls went through last year and the cuts were surprising with the new RFM system. Delta Beta Baby and many of the other ladies will have the correct answer for you, so I'm not going to even try to explain it as I will mess it up as I just learned about it last year. I went through rush - it wasn't called recruitment in the days I was there and cuts did not seem to be so severe in the beginning. But the cuts still came and later so this way does seem to make sense. I worry that the pnm's don't understand the volume of girls coming through the first parties. It's overwhelming on the other side as well...it really is. I would always suggest recs if you don't know any of the girls because that introduces you before the first day even starts. In my day it seems there were 20 girls named Debbie a day. My personal feeling was the first round of invites were more a matter of numbers...I know it doesn't feel that way, but there are over a 1,000 girls going through and possibly 60 or so (I have no idea what quota is) are going to receive a bid.
I was not invited/or cut from chapters after the first round and it felt terrible, happened 2nd round as well, but I wouldn't change a thing about my experience because my house was a perfect fit for me.
Edit - I just saw your RFM question was answered while I was typing this.
Perfect answer...I wish I knew as much, but this is the best place if you have any questions because the GC's on here really know their stuff backwards and forwards!
