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Stat Your Face Off: DVOA Explained

As enigmatic as it is useful. Hate it. Love it. Simply don't understand it.

Join me after the jump where where I'll cure your post-one-and-done insomnia we'll break down DVOA.

Aaron Schatz created DVOA (acronym for Defense-Adjusted Value Over Average - a misnomer really since it's also used to evaluate defenses/defensive play) in 2003. His exact motives are unknown. I like to think a magical falcon flew down from the clouds, spewed fire from its diamond-encrusted beak, and commanded him to ... but that's just me.

DVOA is a fancy schmancy formula that takes the following into account:

(1) Score

(2) Time Remaining

(3) Distance

(4) Field Position

(5) Opponent's Ability

(6) Success Rate (explained here)

Number 5 means that DVOA gets more accurate (assessment-wise) as the season progresses.

Here is the "short version" offered by Football Outsiders:

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 third-and-4 are worth more than five yards on first-and-10 and much more than five yards on third-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.

So why use it?

In a given game, not all offensive/defensive contributions are created equal, even when it seems like they are.

Consider this VERY oversimplified example: Snelling and Turner both score 1 touchdown and manage 50 rushing yards each in a given game. We win. If I say, "they played an equal role in securing the win," more often than not I am wrong.

If Turner's TD and the majority of his yards came when we were already ahead/on first down, then his role in the win was relatively small. On the other hand, if Snelling's TD was the go-ahead TD and the majority of his yards came on third down, then he arguably player a larger role in securing the win.

So why not use it?

As I mentioned above, it's not super accurate early in the season. Also, if a player hasn't played much, one or two really craptastic plays can damage the heck out of his DVOA. Orang3b brought a perfect example of that phenomena to light last week during our discussion of James Harrison:

Me: While his YPC is impressive, it’s VERY inflated. Big runs for slop yards when it did not matter. His DVOA was -21.5 percent, which would have ranked 43/45 RBs (minimum 100 carries), had he actually logged 100 carries (he logged 71 carries).

Orang3b: I think a big part of that bad DVOA is the 2 fumbles (on 71 carries). And regarding the inflated YPC because of big runs: if you take out his 2 biggest runs (50, 36) while he was with the Eagles, he still had a 4.0 YPC there (he was at 2.9 with CLE).

Here is the Football Outsiders explanation of DVOA if you're interested. Discuss!