Wow, I could write a book on that. SHort version: Every crew that applies for the playoffs is assigned a score which is a combination of experience, test scores, meeting and clinic attendance, observer evaluations, and coaches' ratings. Crews are advanced through the playoffs according to those scores, adjusted for a "new blood" process which insures that there are a certain number of crews in the finals every year that have never worked the finals before. It's much more complicated that that, but those are the broad strokes.