How to mess up a good analysis

I guess I don't really know how good this analysis of QB rating differential in relation to winning, because I didn't read it. And I didn't read it because the author commits one of the worst sins of a good analysis...he doesn't bother explaining what it is he's analyzing right off the bat. He spends far too many paragraphs talking about how critical it is, without ever explaining it.

QB rating differential, in case you don't know, is your team's QB rating on offense minus the QB rating allowed by the defense. This is something that should never be explained after the second paragraph, nevermind the seventh.