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Defending Reality

A deeper look at fantasy scoring for team defenses.  

 

Nearly every Fantasy League has different rules for how to score Team Defense. Many use the tried and true method of 1 point for a sack and 2 for a turnover. To add a little variety, many also add 6 points for the rare touchdown and yet another two for the rarest of scores - a safety. Other leagues try to tweak this scoring method by incorporating points against, yards against, or both.

Fantasy Football Scoring - A History Lesson

The basis for fantasy scoring comes from an attempt to quantify an individual player's performance numerically and assign that a value proportional to his team's performance. Touchdowns and yardage usually translate to team success, and the offensive player is rewarded for such productivity.

The second iteration of fantasy scoring came about as an attempt to normalize different positions to a similar scoring system. Quarterbacks produce more touchdowns and yardage than running backs, who produce even more than wide receivers. The result for many leagues was to reduce the points for passing touchdowns and also passing yardage so as to make running backs more valuable. Other leagues go one step further by awarding an extra point per catch to each player to increase wide receiver and tight end values closer to running backs.

What does any of this have to do with Team Defense? I am glad that you asked that question. This article is an attempt to determine how to quantify Team Defense scoring in a manner that reflects the impact a defense has on the outcome of a game, and also to provide a normalized score for a Team Defense that puts the value of a Defense at or near par for other fantasy football positions.

Baseline Defense

First, we have to determine what constitutes a good Team Defense. Is it one that gives up the fewest yards, or the fewest points? An argument can be made for either being the case, so let's take a look at the rankings from last year to see which method more accurately reflects a successful season. The results for the 2012 Season are in Table 1:

Team

YdsVs Rk

PtsVs Rk

Avg Rk

Seattle Seahawks

4

1

2.5

San Francisco 49ers

3

2

2.5

Chicago Bears

5

3

4.0

Denver Broncos

2

4

3.0

Atlanta Falcons

24

5

14.5

Pittsburgh Steelers

1

6

3.5

Miami Dolphins

21

7

14.0

Cincinnati Bengals

6

8

7.0

Houston Texans

8

9.5

8.8

New England Patriots

25

9.5

17.3

Green Bay Packers

11

11

11.0

Baltimore Ravens

17

12.5

14.8

New York Giants

31

12.5

21.8

St. Louis Rams

14

14.5

14.3

Minnesota Vikings

16

14.5

15.3

San Diego Chargers

9

16

12.5

Arizona Cardinals

12

17

14.5

Carolina Panthers

10

18

14.0

Cleveland Browns

23

19

21.0

New York Jets

7

20

13.5

Indianapolis Colts

26

21

23.5

Washington Redskins

28

22

25.0

Tampa Bay Buccaneers

30

23

26.5

Dallas Cowboys

19

24

21.5

Kansas City Chiefs

20

25

22.5

Buffalo Bills

22

26

24.0

Detroit Lions

13

27

20.0

Oakland Raiders

18

28

23.0

Philadelphia Eagles

15

29.5

22.3

Jacksonville Jaguars

29

29.5

29.3

New Orleans Saints

32

31

31.5

Tennessee Titans

27

32

29.5

Table 1: Baseline Defense Rankings

Upon further review of Table 1, for of the Top 5 teams in Points Against were in the 2012 playoffs. Even both Super Bowl teams (Baltimore, San Francisco) and the rest of the Final Four teams (New England, Atlanta) were better in points against than in yardage.  The Ravens, Patriots and Falcons were in the Top 12 in points against but at or below average in yardage as well.  Just like in the past, it appears that Points Against is a better indicator of a good defensive team than just looking at the yardage. We shall adopt Points Against as the baseline for Team Defense.

Sack the Sack

The most common scoring system for Team Defense awards a point for every sack. This seems like a good idea, since it is an accomplishment by the defense to stop the offense from moving downfield, and it is an easy statistic to track. However, how realistic is this as a measure of Team Defense? Do sacks truly translate to team victories?

We obviously need some way to test this idea. Turning to statistics, we find that correlation is a measure of how two groups of statistics relate to one another. The formula used for correlation gives an answer between 0 and 1, with 1 representing a perfect match - 100% correlation. We can use this to see if sacks line up with our baseline, the Baseline Ranking (Points Against) from Table 1.

Table 2 lists the Team Defense rankings for sacks and the Baseline Ranking from Table 1. The correlation factor is given at the bottom of the table.

Team

PtsVs Rk

Sacks

Sacks Rk

Pittsburgh Steelers

6

52

1

Green Bay Packers

11

51

2.5

St. Louis Rams

14.5

51

2.5

Miami Dolphins

7

47

4

Atlanta Falcons

5

44

5.5

San Diego Chargers

16

44

5.5

Denver Broncos

4

41

7.5

Houston Texans

9.5

41

7.5

New England Patriots

9.5

39

9.5

New Orleans Saints

31

39

9.5

San Francisco 49ers

2

38

12.5

Baltimore Ravens

12.5

38

12.5

Minnesota Vikings

14.5

38

12.5

Detroit Lions

27

38

12.5

Seattle Seahawks

1

37

16.5

Cincinnati Bengals

8

37

16.5

Carolina Panthers

18

37

16.5

Indianapolis Colts

21

37

16.5

New York Jets

20

36

19

Kansas City Chiefs

25

35

20

Arizona Cardinals

17

33

21

New York Giants

12.5

32

23

Dallas Cowboys

24

32

23

Buffalo Bills

26

32

23

Cleveland Browns

19

30

25.5

Tennessee Titans

32

30

25.5

Chicago Bears

3

29

27

Jacksonville Jaguars

29.5

28

28.5

Philadelphia Eagles

29.5

28

28.5

Oakland Raiders

28

27

30

Washington Redskins

22

25

31

Tampa Bay Buccaneers

23

20

32

Table 2: Sacks vs. Baseline Defense Rankings

Correlation: 0.542

Based upon the results, it would appear that we are on the right track with some good correlation, right? Well, looking back over the years we have for data, the numbers are really all over the place. Table 3 shows the results going back to 2004:

Year

Sack Rk to PtsVs Rk Correlation

2004

0.509

2005

0.393

2006

0.626

2007

0.444

2008

0.435

2009

0.380

2010

0.545

2011

0.177

2012

0.542

Table 3: Sacks vs. Baseline Defense Rankings 2004-2012

This translates to a wide range of answers, anywhere from a weak correlation (17.7%) between Sacks and Baseline Defensive Ranking to a strong correlation (62.6%). Why would that be the case? The quick answer is that the sack numbers are tightly grouped together. The range of sacks for 25 of the 32 teams is just 28 to 44 sacks, or just one per game. Results this close together will lead to correlations to other data that are unpredictable and all over the map.

So what is wrong with using sacks anyway? The common misconception is that a sack translates readily to the defense getting the ball back for the offense. The reality is that not all sacks are created equal. While a 15-yard sack on 3rd-and-10 would likely result in a Team Defense getting the ball for the offense, a 1-yard sack on first down is not nearly as valuable. However, in the 1 point for a sack scoring system, there is no differentiation between the two different sacks. It would appear that the sack statistic is misleading, and should be replaced by another one.

Turning Over Turnovers

Perhaps we should look harder at the other common statistic used in Team Defense scoring, the turnover. Surely one cannot dispute that turnovers relate strongly to team victories. That has to correlate well with Team Defense rankings, right?

Team

Takeaways

TA Rk

PtsVs Rk

Denver Broncos

44

1

3

New York Jets

41

2

9.5

Arizona Cardinals

35

3

12.5

Minnesota Vikings

33

4

17

Seattle Seahawks

31

7

1

Chicago Bears

31

7

5

New York Giants

31

7

22

Green Bay Packers

30

8

8

San Diego Chargers

29

9.5

9.5

Detroit Lions

29

9.5

19

Baltimore Ravens

28

11

16

Philadelphia Eagles

26

12.5

23

Jacksonville Jaguars

26

12.5

31

San Francisco 49ers

25

14.5

2

Carolina Panthers

25

14.5

12.5

Pittsburgh Steelers

24

16.5

4

New Orleans Saints

24

16.5

32

Miami Dolphins

23

19.5

11

New England Patriots

23

19.5

18

Cleveland Browns

23

19.5

20

Tampa Bay Buccaneers

23

19.5

29.5

Atlanta Falcons

22

22

14.5

St. Louis Rams

21

23.5

14.5

Indianapolis Colts

21

23.5

26

Cincinnati Bengals

20

25

6

Washington Redskins

19

26

28

Buffalo Bills

17

27

27

Houston Texans

16

28.5

7

Kansas City Chiefs

16

28.5

24

Dallas Cowboys

15

30

21

Oakland Raiders

13

31.5

25

Tennessee Titans

13

31.5

29.5

Table 4: Turnovers vs. Baseline Defense Rankings

                                                                                       Correlation: 0.442

OK, that got worse than the previous method (sacks vs. points against).   How can turnovers not significantly contribute to or improve the correlation for a good defensive ranking?

The answer really comes from the mathematics - correlation does not work well with numbers that are close together. From Table 4, you can see most Team Defenses (25 of 32) have from 16 and 31 turnovers, so such a tight grouping will compromise the calculations.

A sanity check is in order - we need to use the common scoring method in its entirety (1 point per sack + 2 points for a turnover) and correlate that result against Average Points (See Table 5):

Team

TAs x 2 + Sks

TAs x 2 + Sks Rk

PtsVs Rk

Denver Broncos

129

1

4

New York Jets

118

2

20

Green Bay Packers

111

3

11

Minnesota Vikings

104

4

14.5

Arizona Cardinals

103

5

17

San Diego Chargers

102

6

16

Pittsburgh Steelers

100

7

6

Seattle Seahawks

99

8

1

Detroit Lions

96

9

27

Baltimore Ravens

94

10.5

12.5

New York Giants

94

10.5

12.5

Miami Dolphins

93

12.5

7

St. Louis Rams

93

12.5

14.5

Chicago Bears

91

14

3

Atlanta Falcons

88

15.5

5

San Francisco 49ers

88

15.5

2

Carolina Panthers

87

17.5

18

New Orleans Saints

87

17.5

31

New England Patriots

85

19

9.5

Jacksonville Jaguars

80

20.5

29.5

Philadelphia Eagles

80

20.5

29.5

Indianapolis Colts

79

22

21

Cincinnati Bengals

77

23

8

Cleveland Browns

76

24

19

Houston Texans

73

25

9.5

Kansas City Chiefs

67

26

25

Buffalo Bills

66

27.5

26

Tampa Bay Buccaneers

66

27.5

23

Washington Redskins

63

29

22

Dallas Cowboys

62

30

24

Tennessee Titans

56

31

32

Oakland Raiders

53

32

28

Table 5: Turnovers and Sacks vs. Baseline Defense Rankings

Correlation: 0.517

Now we're seeing some improvement. The correlation between the basic scoring system and Points Against is certainly better than the turnover ranking correlation alone and is closer to the first score with sacks. The combination of both statistics helped in achieving point separation (ranging from 53 to 129 points) and agreement with the baseline, but there is definitely room for improvement.

The basic argument against using the sack as a standard measure remains - there is little direct correlation between the sack and elite defenses. Another measure of defense should be considered in place of sacks. However, if sacks are going to be eliminated from the Team Defense scoring system, what will be inserted in its place?

Give Me The $#@!! Ball

Let us reconsider the basic premise of Team Defense. Defenses have two main objectives - keeping the opposition from scoring, and getting the ball back for their offense. We have already seen that the first objective is the baseline measure of Team Defense, so we need to quantify the second criteria to the best of our ability to see if this should be the new fantasy football measure of the performance of a Team Defense.

There are two defensive categories of getting the ball back for the offense that are overlooked in the "turnover" category. Defenses succeed in stopping the opponent by forcing the traditional turnover (fumbles and interceptions) and also by forcing punts and stopping the opponent on fourth down. Our new formula for Team Defense needs to have basis in reality to weigh the value of forced punts and turnovers on downs.

Punts happen numerous times during the game, but they rarely result in the defense giving the offense a short field (under 50 yards from a touchdown). As such, forcing a punt has to be viewed as less opportunistic and less valuable than a fumble or interception, which results in a short field about half of the time. Therefore, our formula begins to look like this:

New Team Defense Score = Turnovers (INTs and Fumbles) x 2 + Forced Punts

Now for the second portion of the new formula - incorporation of turnovers on downs. While this can happen anywhere on the field, it is more likely to occur at both a crucial point in the game and also in a position where the opposing team is in scoring territory. While the resulting field position may not be as good as with a traditional turnover, the impact of both getting the ball for the offense and the likelihood that the 4th down turnover kept the opposition off the scoreboard gives this type of turnover approximately equal value to a fumble or interception. Therefore, we modify the formula to be:

New Team Defense Score = Turnovers (INTs + Fumbles + 4th Down Stops) x 2 + Forced Punts

We label this new equation the "Realistic Team Defense" scoring system. Now all that is left is to test our new formula.

Is the Fantasy a Reality

Let us revisit the 2012 season for data once again. Obtaining the two new statistics (4th down turnovers and forced punts), we get the following results:

Team

TOs x 2 + Punts

Reality Def Rk

PtsVs Rk

Denver Broncos

245

1

4

Green Bay Packers

214

2

11

New York Jets

213

3

20

Arizona Cardinals

206

4

17

Minnesota Vikings

198

5

14.5

Baltimore Ravens

195

6

12.5

Pittsburgh Steelers

194

7.5

6

San Diego Chargers

194

7.5

16

Chicago Bears

192

9

3

Seattle Seahawks

191

10

1

Miami Dolphins

189

11.5

7

San Francisco 49ers

189

11.5

2

Houston Texans

187

13

9.5

St. Louis Rams

186

14

14.5

New England Patriots

180

15

9.5

Cincinnati Bengals

177

16.5

8

Detroit Lions

177

16.5

27

Philadelphia Eagles

174

18

29.5

Carolina Panthers

172

19.5

18

Cleveland Browns

172

19.5

19

New York Giants

170

21

12.5

New Orleans Saints

168

22

31

Atlanta Falcons

166

23

5

Tampa Bay Buccaneers

161

24

23

Indianapolis Colts

158

25.5

21

Jacksonville Jaguars

158

25.5

29.5

Buffalo Bills

150

27

26

Dallas Cowboys

146

28

24

Kansas City Chiefs

143

29

25

Tennessee Titans

142

30

32

Washington Redskins

140

31

22

Oakland Raiders

134

32

28

Table 6: All Turnovers and Forced Punts vs. Baseline Defense Rankings

Correlation: 0.635

Definite progress. The correlation between the new and improved scoring system and Points Against is over 63% (63.5%), a sign of a strong correlation and the best correlation so far. This also begins to align well with prior years as shown in Table 7:

Year

Reality Defense Rk to PtsVs Rk Correlation

2004

0.624

2005

0.666

2006

0.688

2007

0.669

2008

0.617

2009

0.649

2010

0.651

2011

0.454

2012

0.635

Table 7: Reality Defense vs. Baseline Defense Rankings 2004-2012

The addition of all turnovers and punts forced has increased the point separation once again, ranging now from 134 to 245 points (a range of 111 points instead of 76 as before in Table 5). For the past nine seasons, only one season was below 60% correlation – 2011.  The smaller correlation in 2011 than in previous years is a reflection of a smaller range from the top to the bottom teams that year. In 2010, the range in Reality Defense was 137 to 226 points, a difference of 89 points.  In 2012, the range is also big – 134 to 245 – comparable to the 2010 numbers.   It appears that there were fewer turnovers in general in 2011, which compresses the range – yet Reality Defense correlation is the best of all the measures of defense year after year.

There are additional benefits to this new equation. First, the scores are higher (average score of 11.1 / game) than under the original system (5.4 / game), which goes more towards a better normalization of the Team Defense position on the fantasy roster. By increasing the average score, the net effect is that a Team Defense is now representative of another normalized position player. Table 8 represents the 2012 average score by position of the Top 12 players based upon the default Footballguys.com scoring system.

Pos

Non-PPR Pts

PPR Pts

QB

30.4

30.4

RB

19.1

22.3

WR

16.1

24.3

TE

9.9

15.8

PK

11.2

11.2

Def*

12.6

12.6

*Based upon the new Realistic Team Defense formula.

Table 8: Average 2012 Fantasy Points / Game for Top 12 Players by Position

Now the Team Defense is comparable to the value of close to a tight end or kicker and just below a Top 12 wide receiver, Top 12 RB or QB. With PPR, the Team Defense declines to a good RB2 or WR2 or an above-average TE2 in value. That would seem to be an appropriate position of value for a strong Team Defense, below a top skill position (QB, RB, WR, TE) but above the lesser valued RB2, WR2, TE2 or kicker position.

One last additional benefit (and variance to the Realistic Team Defense formula) is that the addition of scoring points for a Team Defense scoring play (Touchdown or Safety) allows for the added point value, and also reduces the impact of that event to a lower percentage of the total Team Defense score. Previously, under the original scoring method, teams scored between 53 and 129 points for the season without defensive or special teams touchdowns added (see Table 5). Adding a single touchdown (6 points) varied the overall season score by 5-10%, a large impact. Now with the Realistic Team Defense formula, the range is much larger (134 to 245, see Table 6) so adding a touchdown reduces the impact to 3-5%. This smaller valuation relative to the seasonal performance does seem to be more appropriate.

Conclusion

Adoption of the Realistic Team Defense formula for defensive scoring for fantasy leagues going forward would result in a more accurate representation of the value of a Team Defense and better reflect how the actual defensive unit for each team performs in that particular season. The formula incorporates the significant statistics to quantify how well an actual defense performs, and results in a normalized score relative to the skill position players. The variation of adding back in the relatively rare event of a defensive score reduces the impact of the additional points to less of an overall change to the season Team Defense total, and increases the relative value of a Team Defense closer to that of an upper echelon wide receiver.

One last comment – I get asked this question often over the years.  There are several league hosting sites that can support this scoring format, and I suggest that you ask each site whether they can implement these statistics (forced punts, 4th down stops).  I am positive that MyFantasyLeague.com can score defenses this way, for example, but I do not want to steer anyone towards any particular hosting site.

As always, questions, suggestions and comments are always welcome to pasquino@footballguys.com.

Data Sources

www.nfl.com

www.footballguys.com

 


More from Jeff Pasquino:

I Will Survive: Managing Survivor Leagues - August 25
WR3 By Committee - PPR: Update - August 22
WR3 By Committee: Update - August 22
Perfect Draft: 10 Teams - August 20
Perfect Draft: 12 Teams - August 20
Perfect Draft: 14 Teams - August 20
Perfect FPC Draft - August 20
Average Auction Values - August 19
RB2 By Committee - PPR: Update - August 18
RB2 By Committee: Update - August 18