Aint that an ESPN concoction?LOL
I've never put much stock into QBR.
For example, Cams 3rd down conversions on run plays or his TD runs don't factor into that...
It also doesn't take into account fumbles, sacks taken, etc.
I just think people like making up stats just to have something to talk about, it is a relatively new thing they cam up with just to come up with it. Has no value IMO, you can clearly see yards, TDs, ints, and comp%. Ya know...the stats that matter.