Stat breakdown: How effectively does YPA reflect a quarterback's success?

Is yards per pass attempt an effective measurement of quarterback success? We dig into the stat.

Of the several rookie quarterbacks who were handed the starting reins last season, Derek Carr seemed to receive the most divisive reviews. Though Carr helped an Oakland team largely devoid of talent win three of its last six games, including a 26-24 win over Buffalo’s fearsome pass defense, there was a prevailing feeling that the rookie only stayed afloat due to the Raiders using one of the most safe, vanilla playbooks in recent memory.

There’s one statistic that perfectly illustrates the argument of Carr’s detractors—yards per attempt. Carr averaged just 5.5 yards per throw, one of the worst marks in NFL history among full-time starters.

Fewest YPA in NFL History (min. 3,000 yards) | PointAfter

But how effective of a barometer is it for quarterback performance? Is it a legitimate indicator, or just more noise?

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Pro Football Focus graded Carr as the second-worst starter in the NFL last year (premium required), ahead of only Blake Bortles. But a quarterback’s YPA doesn’t always correspond with his performance on the eye test. Ryan Fitzpatrick, the poster child of veteran game managers, had the fourth-highest YPA (8.0) last year among qualified starters, and Mark Sanchez (7.8) is sixth. And if we include non-qualified quarterbacks, Kirk Cousins, Colt McCoy, Robert Griffin III and Zach Mettenberger all appear in the top 10. There are dozens of stats and scouts out there who would dispute any of those players' place in the league’s elite.

The faults in YPA is obvious—it doesn’t take anything into account beyond the purely quantitative aspect of yards. YPA ignores touchdowns, interceptions and sacks. One could also argue it provides an advantage to quarterbacks in vertical offenses. 

There are several quality signal callers like Ryan Tannehill (6.9, 28th) and Tom Brady (7.1, 21st) whose talent isn’t reflected in the statistic.​ However, there’s also a fair amount of evidence to suggest that the best usually rise to the top of the YPAleaderboards.

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​Tony Romo led the league in YPA (8.5) and QB rating (113.2), a more comprehensive statistic that actually takes into account those aforementioned qualitative events. Aaron Rodgers (8.4), Ben Roethlisberger (8.2), Fitzpatrick (8.0) and Peyton Manning (7.9) rounded out the top five of last season’s YPA rankings. They all got there via different strategies (Romo’s efficiency alongside DeMarco Murray, Rodgers’s overall excellence, Roethlisberger’s deep bombs to Antonio Brown, Peyton’s pinpoint accuracy on short throws), but they were all recognized by YPA.

The below PointAfter graphic shows that there’s a fairly robust correlation between YPA and QB rating. For every one yard increase in YPA, the average quarterback sees his QB rating shoot up by nearly 12 points.

YPA vs. QB Rating in 2014 | PointAfter

Only two players (Brian Hoyer and Drew Stanton) with YPAs greater than 7.0 had a QB rating below 80. And the five worst qualified starters by YPA (Carr, Bortles, Josh McCown, Kyle Orton and Jay Cutler) were all there for obvious reasons.

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McCown was simply awful for Tampa Bay last year by any metric. And the people who say Carr wasn’t given much of a leash by his coaches are ultimately correct—Carr threw 118 passes behind the line of scrimmage, more than any quarterback except for Roethlisberger (124), Stafford (122) and Cutler (120). Roethlisberger and Stafford had more attempts than Carr, while Cutler was restricted by Chicago’s West Coast schemes, which focus on short passes and yards after the catch.

And that’s really what YPA comes down to. To maintain a high YPA, one has to have both the utmost confidence of their coaching staff and the skill to complete a high percentage of passes at every depth level. Last year, Carr, Bortles and Cutler had neither. Guys like Romo, Rodgers and Roethlisberger clearly did.

With Amari Cooper coming into the fold, Oakland should be willing to open up its playbook a little more this year. If not now, why would they have spent their top-five pick on him? If Carr once again finds himself at the very bottom of the YPA rankings by such a wide margin again in 2015, something will have gone horribly wrong in Oakland. At least the statistic can tell us that much.

More from Will Laws:

• The Three Best (and Worst) Teams at Developing Pro Bowlers

• Re-picking the 2005 NBA Draft

• Which NCAA conference is the best at producing Pro Bowlers?

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