odds of getting your preferred house

Good news is that Pref is the round where the PNM has the most say. Say you pref Zeta, if you are anywhere in the top (let’s say 70) PNM’s then you will get a bid there. There is no such thing as “this sorority put me higher on their bid list so I had to get a bid there” at UT. Basically if you are in the sororities top number of girls you get a bid to your #1 pick, but if you are not then you will get your second choice. (Essentially)

Your question is worded a little unclearly. If you mean that if you pref two houses, what are the odds of getting your number one - they are not much better than 50/50. It all depends on where you are on their bid list.

Pretty sure your odds are the same. You’re either high on their list or you’re not. You don’t increase your chance of getting them.

Do not suicide.

Suiciding never helps you get a bid to you number one house. Suiciding does not change your place on a house's bid list and your placement is what determines where you will get a bid. The sororities do not know how pnm's rank them so that is never considered. Here's how it works: Your houses rank each PNM who prefs with them, and you rank your pref houses. The algorithm will start at the top of the houses' bid lists to match their first choices with PNM's who have also put them first. If your first choice house has you high enough on their bid list to match with you before they reach Quota, then you will get a bid from that house. But, if your first choice reaches Quota before you are matched with them, then the algorithm will try to match you with your second choice house. If you are high enough on their bid list to match before they reach Quota then you will get a bid from that house. If you are not high enough to match with them either, then at that point you would get a bid as a Quota Addition and could be matched to either of your pref houses. The algorithm tries to give Quota Additions to their number one house where at all possible, but must also consider their place on the houses' bid lists, total chapter memberships, and other things. If you only rank one of your pref houses and you don't match with them, you are out of the running to be a Quota Addition and you will go without a bid at all.

Pref almost over so this might be too late. Don’t suicide.