DVOA (Defense-adjusted Value Over Average) 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. Special teams are also accounted for with a positive percentage representing an above-average unit versus a negative percentage representing a below-average unit. This system was created by the Football Outsiders, a group which focuses on advanced statistical analysis in the NFL. For a more advanced explanation of DVOA click here
I will utilize the DVOA metric to evaluate both the Detroit Lions and their weekly opponent. This will be done in an effort to take all subjectivity out of predicting Sunday’s contest. Each phase of the game (Offense, Defense, and Special Teams) will be taken into account as well as a rating system that accounts for home-field advantage and injuries. A plus system will be utilized to evaluate each aspect of the game. For example, when a team’s DVOA is superior to another in one phase of the game they will receive a +1. (+1 will be awarded for variations within 10%) When the DVOA gives said team a pronounced advantage in that phase then they will receive a +2. (A pronounced variation is defined as a disparity greater than 20%). And when a team thoroughly outmatches another in a phase of the game they will receive a +3. (This would be defined as a variation greater than 30%). The health of the team will be accounted for with a positive rating assigned to the healthiest team. The team with home field advantage will be given a +1 in every game throughout the season. (Also note that a variation in DVOA of less than 2% will not be grounds for an advantage either way and will result in a push)
You may be asking yourself, “Why should I believe in the DVOA metric?” Because past results are a large indicator of future actions. We can examine what has happened in the past to create an accurate portrayal of future events. You also may be asking “Why is the DVOA metric superior to conventional football statistics, such as total team yardage? Conventional statistics are heavily dependent on the circumstance. Official NFL stats add together the entire yardage gained by a specific team or player without considering the impact of that particular yardage. Down and distance, field position, the current score, time left on the clock, the quality of the opponent – all of these elements matter, and effect how a team operates on each play. This is why DVOA is superior; it accounts for each unique circumstance and compares how well a team or player performs in these situations compared to the league average.
For example, the Arizona Cardinals are trailing the Green Bay Packers by 17 late in the 4th quarter. Green Bay has dropped into a prevent style defense as to not give up any big plays. Arizona recognizes this and acts by converting on 10 to 15 yard intermediate routes on their way down the field. Green Bay consents to these plays considering the juncture of the game. Conventional NFL statistics value plays based solely on net yardage. So, that 15 yard reception late in the 4th quarter is valued equally to a 15 yard reception on the opening drive. However, those receptions were clearly not created equally, given the very different circumstance of each reception. It is clear to me that players and teams need to be evaluated differently given the situation. DVOA has taken this very important factor into account by calculating each team’s success in comparison to the league average in a similar type situation. 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.
Special teams also play an important role in the outcome of football games. DVOA has factored this by creating a metric specifically for special teams. The special team’s metric includes five separate measurements: field goals and extra points, net punting, punt returns, net kickoffs, and kick returns. The special teams rating compares each kick or punt to league average based on the position of the kick, catch, and return. Much like with Offensive and Defensive DVOA measurements, not all special team circumstances are equal. Conventional NFL statistics measure a kicker’s field goal percentage. This is a bit silly as this statistic assumes that all field goals are of equal difficulty, when clearly they’re not. In the DVOA metric, all field goals are compared to league average of kicks in similar situations. This provides a more accurate depiction of the strength of a field goal kicker and thus a special team’s unit as a whole.
Using these DVOA metrics (Offensive, Defensive, and Special Teams) we can compute an objective review of both teams and players. This will be incredibly useful as it will allow us to compare past Detroit Lions metrics (those of the 2011 season and past weeks of the current season) with those of our 2012 opponents.
For our week 1 match-up with St. Louis we obviously don’t have any data to compute with the 2012 team (pre-season doesn’t count). Instead we’ll focus on what the 2011 metrics tell us for this week. For future weeks the focus will be on past weeks in the 2012 season (for week 2 we’ll examine week 1, for week 3 we’ll examine weeks 1 and 2, etc…) as well as past season’s performance. Our evaluation will be broken into Team Offense, Team Defense & Special Teams. Home-field advantage and injuries will also be taken into account.
By now you must be either in a very deep sleep or thinking that this article is longer than Tim Tebow’s throwing motion. Zing! Ok I’ll stop. Let’s get to it!
The 2011 season saw the Detroit Lions offense flourish with Matthew Stafford and Calvin Johnson each enjoying career-best seasons. A review of the 2011 metric shows Stafford as the fifth most valuable quarterback in the league and Calvin Johnson as the most valuable wide receiver in the league.
On the other end of the spectrum was Sam Bradford and the St. Louis offense. According to our metrics Bradford had a truly terrible season. His DVOA percentage ranks at -24.2%; this ranked behind the likes of Colt McCoy, Kevin Kolb, and even Vince Young. Not great company. Furthermore, we often hear about Bradford’s successful rookie campaign. However, the numbers tell us another story. In 2010 his DVOA ranked at -15.6%, again among the worst in the league. His trend of bad play has been a large contributor to the dismal St. Louis offense.
So then, maybe you’re thinking that Sam Bradford may not be any good, but they still can establish the run with Steven Jackson. The numbers don’t quantify this. In terms of fantasy football, Jackson had a nice season. He had 1,146 rushing yards and five touchdowns. However, in terms of his value to his team, his DVOA came in at the negatives, -2.3%. While he shouldered a large workload during the season his value in comparison to other running back’s in the league was on par with Ryan Grant and Michael Bush.
Detroit Team Offense DVOA: 7.1%
St. Louis Team Offense DVOA: -27.2%
Advantage: Lions +3
According to NFL statistics the Lions ranked 23rd in both points and yards allowed. As an understanding of DVOA will tell us, this is largely incomplete and misleading. In terms of DVOA the Lions boasted a top-ten defense, thanks mainly to the fact that they had the league’s best defensive DVOA on third and fourth downs. Their defense was subject to giving up yards, but they were able to get stops when they needed them better than any defensive unit in the league.
The St. Louis pass rush features the emerging star Chris Long who is ranked fourth in total hurries over the past two seasons (75.5), and his 30.5 sacks through four years exactly matches the beginning of his Hall of Fame father’s career (weird)! Robert Quinn, the 2011 first-round pick will start at the other end and James Laurinaitis will return to man the middle-linebacker position. Outside of these players the Rams have completely overhauled their defense. This isn’t necessarily a bad thing as the Rams defense was among the worst in the league last year. New acquisitions include Cortland Finnegan through free agency as well as Michael Brockers and Janoris Jenkins via the draft.
Detroit Team Defense DVOA: -8.1%
St. Louis Team Defense DVOA: 3.4%
Advantage: Lions +2
The Lions were consistently below-average on special teams in 2011. Other than Jason Hanson (I’ll never speak ill-will of the Hanson legend), the Detroit punting unit, consisting of Ben Graham and Ryan Donahue, combined for one of the worst units in the league. Kick and punt returns also suffered as Stefan Logan failed to provide the special team’s boost he did during the 2010 season.
The Rams also fielded a below-average special teams unit in 2011. In the off-season they drafted kicker, Greg Zuerlin (Missouri Western), and cut the struggling incumbent, Josh Brown, the same day. They’ve also made a change at punter, preferring to go with J. Hekker over incumbent Donnie Jones, whose performance was one of the league’s worst in 2011. The team will turn to rookie draft pick Isaiah Pead (Cincinnati) for kick and punt return duties. Pead only returned eight punts in his entire college career, but almost anything would be better than the performance the team got from Quinn Porter and Jerious Norwood on returns last year.
Detroit Special Teams DVOA: -5.1%
St. Louis Special Teams DVOA: -4.8%
The official injury report contains only a total of five players between the Rams and the Lions. The two players for the Lions happen to be key contributors in Chris Houston (ankle) and Louis Delmas (knee). It’s unclear if either will play in the opener. The running back issue in Detroit has also been well chronicled. The Rams are particularly thin at defensive tackle with Michael Brockers (ankle), Matthew Conrath (knee), and Darrell Scott (knee) all missing practice time and uncertain to play.
The Lions will rely on rookie Bill Bentley, special-teamer John Wendling and newly acquired Drayton Florence to fill in for the injured starters. Meanwhile, the Rams are left with starter Kendall Langford, newly acquired Kellen Heard and Jermelle Cudjo at defensive tackle. Depending on the status of the injured defensive tackles on the roster, the Rams could have just three tackles available for Sunday.
The Rams receive a slight advantage given the injury status of the Lions most established defensive backs and the condition of the running back core.
Advantage: Rams +1
Advantage: Lions +1
Our metric comes out to a +5 advantage for the Lions, making them a heavy favorite to open the season with a win. They’ll win this game with relative ease and cover the spread for all you gamblers.
Detroit Lions: 31
St. Louis Rams: 17