I love love football outsiders... they do great work on computing efficiency ratings; however, not all of their metrics are reliable indicators of the reality of football play... But as a statistician and a lover of traditional scouting analysis there are critical things that these limited statistics don't capture. It the same thing that frustrates me about PFF, and that is that we always have to remember that it is the context of the observed human behavior (e.g., football) that gives mean