Who's the best QB... really?

ESPN Stats & Information's new Total Quarterback Rating (QBR) will be worth following this season. It's probably the best statistical measure of a quarterback's effectiveness out there.

As previously noted, the Manning Award used the 2012 QBR to put together its preseason watch list, which includes four Pac-12 quarterbacks: Oregon's Marcus Mariota, Arizona State's Taylor Kelly, UCLA's Brett Hundley and Oregon State's Sean Mannion, who was just named the Beavers starter on Monday.

Total QBR measures a quarterback’s contributions to scoring on each play (passing, rushing, sacks, fumbles, and penalties) accounting for game context (down, distance, yard line, time remaining, and score) and adjusted for opponent strength. It is based on a 0-100 scale where 50 is average.

“Total QBR uses all of a quarterback’s plays and accounts for the context of the game and quality of the defenses faced,” ESPN Stats & Information Sr. Director Jeff Bennett said in a statement with the Manning Award news release. “We are excited to bring a more complete rating system to the fans to allow for fairer comparisons of quarterbacks who play in different types of systems and face various levels of competition."

The Pac-12 blog talked to Bennett and some Stats & Info folks during a recent trip to Bristol, and they explained some of the nuances of the QBR. For example, say a team faces third-and-6 and the QB completes a 5-yard pass. By most efficiency measures, a 5-yard completion would be a positive. But not for QBR, which takes into account down and distance.

As for the 2012 numbers, six Pac-12 QBs ranked among the top 50 in QBR, including four who return this fall. Those six are (with their national ranking):

2. Marcus Mariota, Oregon 87.8

11. Matt Scott, Arizona 79.1

23. Matt Barkley, USC 73.6

33. Brett Hundley, UCLA 68.3

37. Taylor Kelly, Arizona State 67.0

40. Sean Mannion, Oregon State 63.1

For the sake of comparison, here's how things with the NCAA's standard pass efficiency rating (Number is national ranking):

7. Marcus Mariota

9. Taylor Kelly

12. Matt Barkley

26. Brett Hundley

48. Sean Mannion

59. Matt Scott

So there was some difference.