Guild Wars 2

I was wondering how the ranked system worken for solo/team arena.
The ranks on the leaderboards are kinda wierd because some people only have 5 wins and are in the top 20. While other people have lotsof wins and are -200.

Could anyone explain how it works please?

Basically if you win five times against the best players in the game, your rank will be high as opposed to winning 200 times against bad players.

http://en.wikipedia.org/wiki/Glicko_rating_system they use this basically.