How are y'all ranking pledge classes?

I've seen a lot of threads on here talking about how the rankings of sororities changes with the incoming pledge classes, but how do y'all make those judgements? The vast majority of these pledge classes are freshmen, so I wouldn't assume that many people know them already. I'm also confused about the whole AXiD situation since a lot of those girls didn't even go through recruitment so it's not like other sororities got to know them through that process. I generally think that pitting groups of women against each other in some kind of competition for respect is pretty anti-feminist and goes against the whole point of sororities, but if you are going to do it, how?