Alternative Qb rating article.

huevonkiller · Aug 19, 2008

Yes this is one of those stat-fest posts, sorry about that people. This is just for reference in future discussions, etc. I like to have other alternatives to try to measure efficiency. Pro-football-reference also does a decent job at this.

I found an article that tries to weigh QB efficiency and also found a chart of the top Seasons/Careers in the modern era. Basically, "DVOA" is the standard to measure value per pass, and "DYAR" is a volume based statistic which favors more attempts.

I'll post two articles, one is the top seasons by way of DVOA/DYAR, and then the second article below is an explanation of how DVOA/DYAR was derived. I left the DYAR chart/explanation out of this post, so just click on the links to decipher that.

(modified slightly from article to make it easier to understand)
Top 8 QB Seasons by Passing DVOA, 1995-2007, 300+ Passes
Peyton Manning 2004 DVOA = 60.9%
Tom Brady 2007 DVOA = 56.9%
Peyton Manning 2006 DVOA = 51.0%
Randall Cunningham 1998 DVOA = 42.8%
Peyton Manning 2007 DVOA = 40.6%
Chad Pennington 2002 DVOA = 40.6%
Peyton Manning 2005 DVOA = 40.4%
Vinny Testaverde 1998 DVOA = 39.8%
David Garrard 2007 DVOA = 37.4%
John Elway 1998 DVOA = 37.3%

As you might imagine, one man dominates the list of the best seasons, and his name is not "Eli." Peyton Manning’s 2000 and 2003 seasons also rank in the DVOA top 20 (minimum 100 passes). In the endless, irrational arguments about Brady and Manning, one thing has always been clear: except in 2007, Manning always had the better statistics. If you want to argue about that further, make sure to use the Irrational Brady-Manning Thread and don’t bother the rest of us. (Scary thought: according to the new, improved opponent adjustments, both Brady and Manning faced an above-average set of pass defenses last year.)
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Source: Football Outsiders

METHODS TO OUR MADNESS

THE SHORT VERSION: DVOA is a method of evaluating teams, units, or players. It takes every single play during the NFL season and compares each one to a league-average baseline based on situation. DVOA measures not just yardage, but yardage towards a first down: five yards on 3rd-and-4 are worth more than five yards on 1st-and-10 and much more than five yards on 3rd-and-12. Red zone plays are worth more than other plays. Performance is also adjusted for the quality of the opponent. DVOA is a percentage, so a team with a DVOA of 10.0% is 10 percent better than the average team, and a quarterback with a DVOA of -20.0% is 20 percent worse than the average quarterback. Because DVOA measures scoring, defenses are better when they are negative. For more detail, read below.

Please feel free to contact us with questions and comments about our new statistics using the contact form.
DVOA EXPLAINED

The majority of the ratings featured on FootballOutsiders.com are based on DVOA, or Defense-adjusted Value Over Average. DVOA breaks down every single play of the NFL season to see how much success offensive players achieved in each specific situation compared to the league average in that situation, adjusted for the strength of the opponent.

The NFL determines the best players by adding up all their yards no matter what situations they came in or how many plays it took to get them. Now why would they do that? Football has one objective-to get to the end zone-and two ways to achieve that, by gaining yards and getting first downs. These two goals need to be balanced to determine a player's value or a team's performance. All the yards in the world aren't useful if they all come in eight-yard chunks on third-and-10.

The popularity of fantasy football only exaggerates the problem. Fans have gotten used to judging players based on how much they help fantasy teams win and lose, not how much they help real teams win and lose. But fantasy scoring skews things by counting the yard between the one and the goal line as 61 times more important than all the other yards on the field. Let's say Steve Smith catches a pass on third-and-15 and goes 50 yards but gets tackled two yards from the goal line, and then DeShaun Foster takes the ball on first-and-goal from the two-yard line and plunges in for the score. Or, let's say that the Falcons take a touchback on the opening kickoff, and the Carolina defense stuffs Warrick Dunn twice, and on third-and-10 Michael Vick throws the ball into the arms of Ken Lucas, who gets taken down by Alge Crumpler at the two-yard line. Then on the ensuing first-and-goal, Foster scores a touchdown.

Has Foster done something special? Not really. When an offense gets the ball on first-and-goal at the two-yard line, they are going to score a touchdown five out of six times. In the first situation, Foster is getting the credit that primarily belongs to the passing game. In the second situation, Foster is getting the credit that primarily belongs to the defense.

DVOA does a better job of distributing credit for scoring points and winning games. It uses a value based on both total yards and yards towards a first down, based on work done by Pete Palmer, Bob Carroll, and John Thorn in their seminal book, The Hidden Game of Football. On first down, a play is considered a success if it gains 45 percent of needed yards; on second down, a play needs to gain 60 percent of needed yards; on third or fourth down, only gaining a new first down is considered success.

We then expand upon that basic idea with a more complicated system of "success points." A successful play is worth one point, an unsuccessful play zero points. Extra points are awarded for big plays, gradually increasing to three points for 10 yards, four points for 20 yards, and five points for 40 yards or more. There are fractional points in between. (For example, eight yards on third-and-10 is worth 0.63 "success points.") Losing four yards is -1 point, losing 12 yards is -1.8 points, an interception is -6 points, and a fumble is worth anywhere from -1.70 to -3.98 points depending on how often a fumble in that situation is lost to the defense - no matter who actually recovers the fumble. Red zone plays are worth 20 percent more, and there is a bonus given for a touchdown.

(The system is a bit more complex than the one in Hidden Game thanks to a number of improvements since we launched the site in 2003.)

Every single play run in the NFL gets a "success value" based on this system, and then that number gets compared to the average success values of plays in similar situations for all players, adjusted for a number of variables. These include down and distance, field location, time remaining in game, and current scoring lead or deficit. Teams are always compared to one standard, as the team made its own choice whether to pass or rush. However, when it comes to individual players, rushing plays are compared to other rushing plays, passing plays to other passing plays, tight ends get compared to tight ends and wideouts to wideouts.

Imagine two running backs who each gain three yards. Player A gains three yards under a set of circumstances where the average NFL running back gains only two yards (for example, third-and-1), it can be argued that Player A has a certain amount of value above others at his position. Likewise, if Player B gains three yards on a play where, under similar circumstances, an average NFL back would be expected to gain five yards (for example, second-and-15), it can be argued that Player B has negative value relative to others at his position.

Once we have all our adjustments, we can find the difference between this player's success and the expected success of an average running back in the same situation (or between this defense and the average defense in the same situation, etc.). Add up every play by a certain team or player, divide by the total baseline for success in all those situations, and you get VOA, or Value Over Average.

Of course, the biggest variable in football is the fact that each team plays a different schedule. By adjusting each play based on the defense's average success in stopping that type of play over the course of a season, we get DVOA, or Defense-adjusted Value Over Average. Rushing and passing plays are adjusted based on down and location on the field; receiving plays are also adjusted based on how the defense performs against passes to running backs, tight ends, and wide receivers. Defenses are adjusted based on the average success of the offenses they are facing. (Yes, this is still called DVOA, for the sake of simplicity.)

The biggest advantage of DVOA is the ability to break teams and players down to find strengths and weaknesses in a variety of situations. In the aggregate, DVOA may not be quite as accurate as some of the other, similar "power ratings" formulas based on comparing drives rather than individual plays, but, unlike those other ratings, DVOA can be separated not only by player but also by down, or by week, or by distance needed for first down. This can give us a better idea of not just which team is better but why, and what a team has to do in order to improve itself in the future. You will find DVOA used by Football Outsiders in a lot of different ways. Because it takes every single play into account, it can be used to measure a player or a team's performance in any situation. All Minnesota third downs can be compared to how an average team does on third down. J.P. Losman and Kelly Holcomb can each be compared to how an average quarterback performs in the red zone, or with a lead, or in the second half of the game.

Since it compares each play only to plays with similar circumstances, it gives a more accurate picture of how much better a team really is compared to the league as a whole. The list of top DVOA offenses on third down, for example, is more accurate than the conventional NFL conversion statistic because it takes into account that converting third-and-long is more difficult than converting third-and-short, and that a turnover is worse than an incomplete pass because it doesn't provide the opportunity to move the other team back with a punt on fourth down.

One of the hardest parts of understanding a new statistic is grasping the idea of what numbers represent good performance or bad performance. We try to make that easy with DVOA, because it gets compared to average. Therefore, 0% always represents league-average. A positive DVOA represents that the offense is more likely to score, and a negative DVOA represents that the defense is more likely to stop them. This is why the best offenses have positive DVOA ratings (Indianapolis in 2005: +26.9%) and the best defenses have negative DVOA ratings (Chicago in 2005: -21.8%).

Ratings for teams and starting players generally follow that scale, with the best being around 30% and the worst being around -30% (opposite for defense). However, because the baseline represents four years of play (2002-2005) no year will average exactly 0%. Over the past four years, offensive levels have bounced back and forth, so in 2002 and 2004 the league average was positive, and in 2003 and 2005 it was negative.

Team DVOA totals combine offense and defense, and the team total is given by offense minus defense to take into account that better defenses are more negative. (Special teams performance is also added, as described below.)
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Source: Football Outsiders

tim · Aug 19, 2008

No Brett Favre on there. Something must be wrong!

Speaking of that, funny to see Pennington on there.

huevonkiller · Aug 19, 2008

tim said: ↑

No Brett Favre on there. Something must be wrong!

Speaking of that, funny to see Pennington on there.
Click to expand...

Yeah it is a pass per value table, that adjusts for the type of defense one faced.

Pro-football-reference has the best blogs for empirical discussions though, I visit them the most for that sort of thing. I'll dig up some of their own conclusions about winning correlation later. I personally think they're better than the source I provided. :]

I can't read through too much of this stat crap though, it is tedious. Haha.

Giantsfan1 · Aug 20, 2008

Chad Pennington does have the highest pass percentage in NFL history.

Basically, he can't throw past 20 yards, so he just does a whole bunch of dump offs which results in pretty stats and a mediocre actual game but he has no arm so he can't win his team a game, but vice versa

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Alternative Qb rating article.

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Alternative Qb rating article.

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