In terms of player evaluation (which was a large part of my masters studies), Ultimate is very much in its infant stages. As the game develops, I am sure that this will improve. However, as it stands, the selection process of players for teams or countries is quite simplistic. Have some tryouts. Watch the match-ups. Trust your minds eye.
The problem with the mind's eye is that it lies. We all love the teammate who can lay out and make d's. When we win, he/she gets a lot of credit. But over the course of a game, a tournament, a season, that d means a lot less in determining the outcome of our team's finish than our mind believes. Inefficient players who make lots of d's but also make too many drops and throwaways might be overrated by the time tested scouting system. Sadly, they sometimes get the edge in team selection over a more efficient, less flashy player.
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Hey
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Teams are restricted by resources. It costs money and time to have games taped and analyzed. Player stats are not tracked even during tourney games for most competitive teams. Even worse, we sometimes hear the "stats are for nerds" line from the same people who say they'll seek any legal competitive edge to win. If you're too lazy to learn or stupid to fathom, just admit it and step aside. Insult gun back into its holster.
Improving player evaluation will take time. Someone will lead the charge and get an edge, and then others will try to copy the success. Look at baseball and Sabermetrics. Other pro leagues are trying to emulate baseball's "moneyball" ideas (Facing tougher challenges due to the organic nature of their sports).
How do we improve evaluation? Find someone/some way to track your teams stats. Develop working groups of ultimate players with the educational background to use the data.
I am more than willing to participate.