Only The Truth

QBR Team Efficiency Under Review

07/22/2013 13:28

Almost every stat or rating has a limited effectiveness in some way. This site has never been about using one stat to describe everything that occurs in a game or over the course of an entire season. It has rather been about using a collection of highly accurate stats with a significant correlation to winning football games to serve as a guide when conducting any kind of analysis.

 

Here are some of the best efficiency ratings and their flaws:

 

  • Teams with the better Plays/TD score won 90.6% of the games in 2012. However, this stat doesn't answer the question "Why?." Why was one team able to play at such an efficient rate while the other team did not? What factors were involved? Fans will have to look at the box score to find reasons. All this stat says is one team averaged about 18 plays per touchdown while the other team averaged about 23 plays per touchdown. It is great for ranking teams in order of efficiency, but it fails to explain what went on during the game that led to this rating.
  • Teams with the better Yards/TD score won 83.9% of the games in 2012. This stat has the same flaw that the Plays/TD stat has. It is limited in how much it explains why one team was better than the other.
  • Teams with the better QBR won 82.0% of the games in 2012. However, many teams in 2012 had excellent running games and poor QBs. This meant much of the success for many teams was a result of a good running game, which will never be included in a QBR unless it is done by the quarterback. Obviously, the QBR has a very high success rate, but it still fails to cover every aspect of both offenses in a game. It is very descriptive, unlike the Plays/TD stat, but it doesn't include everything.
  • The QueueStats general Team Efficiency Rating is a relative stat that takes the NFL rankings in Plays/TD, Net QBR, Net Points and Net Misc and gives a weighted value. This is great, but it is a rating that is dependent on other ratings, making it more abstract. It also fails to give a score that carries over from season to season. If two teams during separate seasons ranked 1st in each category, they would have the same score, but there is no chacne they are equal in efficiency. It is a great stat that is simply relative to one single season.
  • The Points/Possession stat is also very useful in generating a stat that measures how often a team scores, since teams play at different paces. This is essentially accomplishing the same thing as the Offensive and Defensive Efficiency Ratings used by the NBA, which helps deal with that issue of pace. However, this stat again fails to answer any questions about why or how a team was able to succeed or why it struggled.

 

All of these stats are the best in football and can be used to accurately measure efficiency. However, it has always been a balancing act between using an abstract stat that spits out a score with a high correlation to success and a descriptive stat that maintains that correlation.

 

While there is no such thing as a perfect stat or rating, there is one that is very close. The QBR Team Efficiency stat takes the concept of the QBR stat measuring only QBs and applies it to the entire offense. Since the QBR is very descriptive, this rating can give fans a very good idea as to why a team is having success.

 

Here are the elements measured in the stat and what is included in each element:

  1. Net Points - includes the points scored by the offense minus the points scored by the opposing defense. This means the points scored by the defense don't count in this figure, but they do take away from the opponent's offensive total. The points total is then converted into touchdowns and calculated as a percentage based off of the number of plays the team ran, with a weighted to value. Both rushing and passing touchdowns are included.
  2. Turnovers - all team turnovers (offensive and special teams) are calculated the same way as the points total and with the same weighted value.
  3. Third Down Conversions - Since there is no completion percentage for the entire offense, 3rd/4th downs are used as a percentage with a weighted value.
  4. Yards per play - This measures a team's ability to move the ball. Even if it doesn't always result in points, it is still better to be able to gain yards than go 3-and-out most of the time.
  5. Sacks, tackles For loss (TFL) and QB hurries - this measures the offensive line's ability to protect the QB from penetrating defenders as well as tackling the RB in the backfield. 
  6. Special Teams scores - many teams score on special teams as well. This stat includes a fixed value for a touchdown and awards the team that score for each special teams score.

 

Here is what it would look like with data from a box score:

 

Game 1 of the 2012 Regular Season between Pittsburgh and Denver. Denver won the game with a final score of 31-19.

Team Plays Net Pts Yards TOs NP 3DC ST Tm Eff
PIT 71 12 284 1 30.28 57.89 0.0 48.31
DEN 55 24 334 1 12.73 55.56 0.0 95.38

 

Breaking Down the Game

  1. The first part of this is to remember everything is going to be calculated as a percentage based off of the number of plays ran by the offense.
  2. Both teams had 7 less points than the final game score because Denver's offense did not score that touchdown by Tracy Porter. The defense did. However, Pittsburgh is also penalized for "helping" the Broncos score. This means both teams lose 7 points from the final score.
  3. There were no special teams scores, so no further points were subtracted from the Net Points total. Also, no team was awarded 15 special teams points, the approximate value of a touchdown, since there weren't any.
  4. Denver has a great net points total with fewer plays, which gives them a huge advantage in the rating since they were more "efficient".
  5. Denver also had more yards on fewer plays, meaning the offense was much more explosive.
  6. Both teams had 1 turnover, but since it is as a percentage, Denver actually lost more points since the offense ran fewer plays.
  7. Denver also had a much lower Negative Plays (NP) rating, which means Denver put a lot more pressure on the QB than Pittsburgh did.
  8. Both teams converted their third and fourth downs about evenly at 55-57 %.
  9. The rating then weighs the values and spits out a score based on the raw data above.

 

Denver was nearly twice as efficient as Pittsburgh with a score of 95.38 - 48.31. Denver also won the game with a significant margin. 31-19. Yes the game was close for most of the game, but so were the teams, efficiency-wise, until the 4th quarter, where Denver outscored Pittsburgh 17-7. 

 

This is just one of many examples where the stat allows fans to see why teams have better ratings than the others. Points, turnovers, yards, QB pressures and third downs are all important elements to a game and are included here in detail. It will be very clear in this formula as to why a team won or lost a game.

 

Conclusion

No stat here is used often without doing research on its validity. Over the past two years, this stat has posted an incredibly high correlation to success. From 2011-2012, the team with the better score in this rating has gone 466-45 (91.2%). In 2011, the team with the better record in this stat won the game 92.6% of the time. With the numerous upsets and bizarre performances in 2012, the percentage dropped a little.

 

Still, this rating is the only rating to combine detailed stats encompassing the entire offense with an incredibly high correlation to winning games. The NFL has always been about efficiency over volume, and perhaps no stat accomplishes this better. Teams don't win because of just one area of success, usually, but rather a collection of performances in different areas of the game.

 

The NFL is a team game, and no stat in football illustrates this better.

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Luke Clementson