An introduction to advanced statistics in football and how it can help teams succeed

One of the most discussed revolutions in sports over the last fifteen years or so has been the introduction of sabermetrics, or so called ‘advanced stats’. The revolution started in baseball and was popularized by the Oakland A’s general manager Billy Bean, who was portrayed in the 2011 movie "Moneyball" starring Brad Pitt. Slowly, other team sports have developed their own metrics that have helped fill in the gaps in our knowledge. A lot of the findings go against popular coaching – and announcing - clichés, and may challenge the belief systems of even the most knowledgeable fan.

All the advanced stats really are is the probability of an outcome. If the chances of X happening are 99 times out of 100, pointing to the one time the outcome was wrong doesn’t necessarily disprove the stat. In a football example, this means that if the math shows it’s smarter for a team to go for it on fourth down over punting, and they don’t get a first down, that doesn’t mean that it was a bad call; it just means that they made the right decision but failed to execute. Stats may help inform decisions but they don’t always account for the human elements of games which should never be discounted completely.

Here’s a quick examination of some of the notable findings and a brief explanation to key stats in football as found on the indispensable www.footballoutsiders.com. Every stat and explanation can be found on their website unless otherwise noted and the writers there deserve the credit for the findings.

1. Establishing the Run is a Myth

Ask anyone over thirty what the phrase "Steeler football" means to them and they’ll tell you defense and running the football. Lots of Sunday morning pregame shows list getting running backs involved in games early as a key to victory. However, unless the team is playing a defense that really struggles against the run, or you have a running back that is averaging close to six yards per attempt, this is a bad strategy. There is no correlation between giving a running back a majority of carries early in the game and winning. Rather, teams that win with a high number of rushing attempts because they already have the lead and want to run out the clock, for which running is obviously very useful. Having balance on an offense is indeed key, but there’s no need for offensive coordinators to force the run when planning a game.

2. Running the Ball on third/Fourth and short situations is better than passing

One key where running the ball is a smart play is when an offense is one or two yards away from the goal line or first down. Every football fan can tell you that teams like to throw the ball now more than they ever have in NFL history, with mediocre quarterbacks routinely topping 3000 yards now. In general, pass plays pick up more yards than run plays but in specific situations it may be prudent to run the ball. Runs in situations where you’re one to two yards away from the goal line work 66% of the time while passes work 52% of the time. On fourth down, the stats are even more skewed to the run with 69% of runs working while 48% of passes work. However, teams pass 67% of the time on third and short and 77% of the time on fourth and short. Nowhere is this situation better illustrated than anytime you see a team facing a third and two, and then line the quarterback up in the shotgun an extra five yards away from the first down in an empty backfield. Unless the quarterback is Russell Wilson, or some other scrambling quarterback, not only have you increased the amount of yards the offense needs to cover, you’ve also telegraphed to the defense what your plan is. As we covered in the above point, offenses need balance so removing the threat of the run isn’t a great idea. While teams can’t run every time they face this situation, they can however pass a lot less than they do now to maintain some balance and increase their chances at converting.

3. DVOA and DYAR

Two of the most frequently cited advanced stats are DVOA and DYAR. Below is a brief summary of what each stat entails

DVOA stands for Defense-adjusted Value Over Average which is a fancy way of saying it measures how a player or team does if they were replaced with an average player on a given play. Consider this example in which two players both rush for three yards from Football Outsiders: "if Player A gains three yards under a set of circumstances in which the average NFL running back gains only one yard, then Player A has a certain amount of value above others at his position. Likewise, if Player B gains three yards on a play on which, under similar circumstances, an average NFL back gains four yards, then Player B has negative value relative to others at his position."

Here is a slightly longer explanation from Football Outsiders of what else is considered in the statistic: "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."

By using the averages of each position, DVOA helps compare players who may have faced different opponents in a season. This means a receiver that has more yards than others due to playing a bunch of bad defenses may have a lower DVOA than a receiver with less total yards but fared better than average against a bunch of good defenses. When looking at DVOA rankings keep in mind that 0% is average and the further you move from zero the better or worse a team or player is (obviously on offense it’s better to have a high DVOA while defenses want a low DVOA).  You can learn more about DVOA here.

DYAR stands for Defense-adjusted Yards Above Replacement, and it is more of a cumulative stat than DVOA which is a per-play stat. In a nutshell, DYAR tells you how valuable a player is over the course of a season while DVOA tells you how valuable they are per play. A player may have a high DYAR but an average DVOA because he’s used more consistently than a player who is a big play specialist. Antonio Brown led all receivers in DYAR in 2015 but was ninth in DVOA. Tyler Lockett on the Seahawks was 15th in DYAR but third in DVOA in the same time period. Antonio Brown was thrown at 193 times versus Lockett’s 69 times. Per play, Lockett did more than Brown, but over the course of a season it’s way better to have Brown on your team than Lockett. You can learn more about DYAR here if you scroll down.

4. Rankings based on DVOA vs. Traditional Rankings

Traditional rankings that you find in the newspapers, on espn.com, and talk shows primarily use total yards to determine rankings. Total yards don’t account for teams that are getting blown out and can rack up lots of passing yards in garbage time when the game has already been decided. Nor does it account for strength of schedule like DVOA does. As such according to ESPN here are the ten best offenses in 2015 based on total yards:

ESPN

1. Arizona

2. New Orleans

3. Pittsburgh

4. Seattle

5. Tampa

6. New England

7. Atlanta

8. New York Giants

9. San Diego

10. New York Jets

And here are the ten best offenses according to DVOA which takes the situations in which the yards were earned into account, as well as strength of schedule.

DVOA

1. Cincinnati

2. Seattle

3. Pittsburgh

4. Arizona

5. New England

6. Kansas City

7. New Orleans

8. Carolina

9. Buffalo

10. Chicago

What should jump out to you when you look at these rankings is that according to ESPN, six of the best offenses belong to teams that didn’t make the playoffs. But when you adjust them to account for the situations in which the yards were earned, it drops to only three of the best offenses were from teams that missed the playoffs.

Obviously there are things that stats can’t account for. It is still impossible to separate a wide receiver from a quarterback and a running back from an offensive line. It is also impossible to separate all those from the scheme the coordinator is running. All those factors combine to influence a player. However, stats in general can help tell a more complete story about a team and their successes or failures.