Naughty Dog sheds light on "Skill levels and the Ranked playlist"

Justin of Naughty Dog says, "Reading over forums, blog comments and Tweets, we wanted to talk a bit about Skill level and the Ranked playlist.

Skill is only counted for games played in the specific Ranked playlist. Your performance in the other playlists has no effect whatsoever on your Skill level. Another thing to be aware of ..."