It’s not a ‘voting’ thing, it’s a numbers thing. They keep statistics on everything. They determine #1 (for Rush) by the number of matches, the houses that ‘take quota’ or now ‘quota plus’ (which is allowed by the algorithm), that had the most acceptances for parties.
After all the parties are completed, the house makes a list of who they are extending bids to and the order, and the PNM do the same and order them. The more #1 matches on both list, the better for both, so the more ‘points’ (they aren’t really points awarded) and the house with the most is #1. There is a neutral group doing the matching and they know which house had the most matches.
Some houses don’t take quota, some don’t match as many #1 choices from the PNM but match #2 or #3 picks.
Does it matter if a house is #1 or #4? Probably not. Some women don’t want to be in a really big house and concentrate on the smaller houses during Rush. The house I was in was much smaller and we never took quota, and in fact got about half of our members during ‘open’ rush or spring (organized) Rush. Houses that took quota in the fall didn’t even rush in the spring.
So by the numbers we weren’t as popular. WE thought we were terriffic.