Mothman wrote:However, to me, this sort of game and the accompanying ratings point out how deceptive such ratings can be rather than underscoring how great a player was in a given game. Bridgewater was basically an effective game manager on Sunday and I'm not using that term in the negative sense it's often used. I'm just saying that Peterson's performance keyed the offense, the defense had a strong game and Bridgewater did a nice, solid job in his role. If his performance appears "magnificent" or "historically great" by ESPN's QBR standard I think it just shows that Total QBR isn't an effective stat from which to draw such conclusions.
I couldn't agree more. I have long been a critic of the QBR simply because I don't know the specific process by which it is determined.
Here is a link that describes in (very) general terms what factors are considered when calculating the QBR, but you'll note it was changed in 2012 and in 2013 (after first being used in 2011), So, basically, in its 4 years of existence, it's formula has been changed/modified twice already. I like using a passer rating for a better "feel" on how the quarterback is performing, not because it is "more accurate" but because it is more "transparent." I know how it is calculated, and therefore, know the weaknesses/biases in the calculation(s).
Here is a comment from the linked Wikipedia article:
Further controversy erupted when the Total QBR system gave the Denver Broncos' Tim Tebow a higher rating than the Green Bay Packers' Aaron Rodgers in their respective Week 5 contests in 2011. Noting that Rodgers completed 26 of 39 passes for 396 yards and two touchdowns in a win over the Atlanta Falcons, while Tebow completed four of 10 passes for 79 yards and a touchdown, and six rushes for 38 yards and a touchdown, in a loss to the San Diego Chargers, Mike Florio of Profootballtalk.com wrote that he'll "continue to ignore ESPN’s Total QBR stat."[12] Rodgers himself was surprised: "I saw the [QBR stats] and chuckled to myself. I played a full game, [Tebow] played the half. He completed four passes, I completed 26. I think it incorporates QB runs as well ... The weighting of it doesn't make a whole lot of sense"