Like a sack goes against a QB. Everyone, even if its not his fault. The new QBR sucks..
Total QBR, ESPN's metric, is designed to prioritize certain plays above other. For example, a TD in garbage time doesn't equate the to same math as a TD in the final minute of a close game, or a TD that gives your team the lead in the 3rd quarter.
It also accounts for things like an INT thrown in the desperate moment of a final hail mary attempt, vs a TD thrown against a bad defense in the 1st quarter, and goes even so far as to account for the difference between a long INT vs. a short INT.
I tried to read through it all when they did their big "announcement" on it, but to be honest, I found the BCS standing calculations to be easier to understand... and I didn't understand those either.
I saw TQBR as an attempt to bring Sabermetrics to football, and if you are going to do that, just give us a park adjusted WAR for every player, and we will still be just as confused, but we will at least have one single number to argue over.
Sabermetrics thinking is never going to apply to football because the playcalling is the X factor the players don't control.
In baseball, each player is expected to reach a certain number of at-bats, and have a certain number of fielded balls for their position. It normalizes the metrics. In football carries don't get split evenly among runnings backs, some teams use a featured back, some by platoon, some use a two back system... and some teams run more and some pass more.
It skews the numbers when trying to make comparatives, and it's something the player on the field has no control over.