how do sororities decide?

[swtlilsoni]

I went through formal recruitment, and ended up getting invited back to only my last choice for pref. I did feel like I connected well with some of the other chapters but I dont know what happened.

Anyway, my question is, how do sororities generally decide who to invite back? I know the exact formula is secret and varies from house to house but I just want a general example of what type of system is used (I know it may not be the system used in all sororities but even if it is used in a few the example would be helpful). Like, is it democratic style (voting)? If thats the case ... I dont really see how that can work because when we went to visit each house, we were paired up with a sister and would talk to them, and sometimes another sister would come join us .. and it wasn't up to us at all how many sisters joined us .. it was completely random. So at some houses I spoke to 4 or 5, but at others I only spoke to 2. So if voting is used, doesnt that highly depend on how many sisters happened to come join you? And isnt that completely arbitrary?