Haphazardly. I've actually been told otherwise but man sometimes it sure feels like a cluster... LOL
We have used everything from paper brackets, to brakelope, to pen and paper swiss, and custom software. It's just a real big crapshoot. I like offering varied formats, and there's really no one-size-fits-all solution. It seems like the most popular format is, sadly, Herb. It's not my favorite qualification type at all. I really prefer match play formats.