top nationally

There is no such thing as national rankings unless you rank on something objective. You can rank on total number of members, total number of chapters, total money raised for their foundation, etc. But you can't rank for popularity because people have different opinions about which house is the most preferable even at the same university. Even if you could somehow do that, it would be completely silly to pay attention to it because houses that are great one place are terrible at another. No one is going to join a house just because you put some (fake) rank saying that they're great nationally. For example, who at OU would think ATO and Beta were even. That's laughable. And we don't even have Theta Chi.