pledge class size

It's not how many register, it's how many sign their cards after the pref parties that determines new member class sizes. There will be fewer at the end of rush than registered because a few girls get released from all houses but the vast majority of girls who don't go all the way to the end are voluntary drop outs because they don't like the houses they get back. Quota is based on the number of girls signing cards divided by the number of sororities, and then some houses take more than that due to the Quota Plus system. Quota Plus ensures that every pnm who ranks each house where she prefs will get a bid, even if it puts some houses over Quota.