Defending Reality: Team Defense Scoring - Footballguys

A deeper look at fantasy scoring for team defenses.

Nearly every Fantasy League has different rules for how to score a Team Defense. Many use the tried and true method of one point for a sack and two for a turnover. To add a little variety, many also add six 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 last season are in Table 1:

Team
Yards-Against Rank
Points-Against Rank
Average Rank
Minnesota Vikings
1
1
1
Jacksonville Jaguars
2
2
2
Los Angeles Chargers
15
3
9
Philadelphia Eagles
4
4
4
New England Patriots
29
5
17
Baltimore Ravens
12
6
9
Pittsburgh Steelers
5
7
6
Atlanta Falcons
9
8
8.5
Chicago Bears
10
9
9.5
New Orleans Saints
17
10
13.5
Carolina Panthers
7
11
9
Los Angeles Rams
19
12
15.5
Seattle Seahawks
11
13.5
12.25
Dallas Cowboys
8
13.5
10.75
Kansas City Chiefs
28
15
21.5
Cincinnati Bengals
18
16
17
Tennessee Titans
13
17
15
Buffalo Bills
26
18
22
Arizona Cardinals
6
19
12.5
Oakland Raiders
23
20
21.5
Detroit Lions
27
21
24
New York Jets
25
22.5
23.75
Tampa Bay Buccaneers
32
22.5
27.25
Denver Broncos
3
24
13.5
San Francisco 49ers
24
25
24.5
Green Bay Packers
22
26
24
Washington Redskins
21
27.5
24.25
New York Giants
31
27.5
29.25
Miami Dolphins
16
29
22.5
Indianapolis Colts
30
30
30
Cleveland Browns
14
31
22.5
Houston Texans
20
32
26

Table 1: Baseline Defense Rankings

Upon further review of Table 1, four of the Top 5, five of the Top 7 and nine of the Top 12 teams in Points Against were in the 2017 playoffs - and the other three playoff teams (Kansas City, Tennessee, and Buffalo) just barely missed the mark (all finished in the Top 18). 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
Points-Against Rank
Sacks
Sacks Rank
Pittsburgh Steelers
7
56
1
Jacksonville Jaguars
2
55
2
Carolina Panthers
11
50
3
Los Angeles Rams
12
48
4
Los Angeles Chargers
3
43
5.5
Tennessee Titans
17
43
5.5
New England Patriots
5
42
8.5
Chicago Bears
9
42
8.5
New Orleans Saints
10
42
8.5
Washington Redskins
27.5
42
8.5
Baltimore Ravens
6
41
11.5
Cincinnati Bengals
16
41
11.5
Atlanta Falcons
8
39
13.5
Seattle Seahawks
13.5
39
13.5
Philadelphia Eagles
4
38
15.5
Dallas Cowboys
13.5
38
15.5
Minnesota Vikings
1
37
18
Arizona Cardinals
19
37
18
Green Bay Packers
26
37
18
Detroit Lions
21
35
20
Cleveland Browns
31
34
21
Denver Broncos
24
33
22
Houston Texans
32
32
23
Kansas City Chiefs
15
31
24.5
Oakland Raiders
20
31
24.5
San Francisco 49ers
25
30
26.5
Miami Dolphins
29
30
26.5
New York Jets
22.5
28
28
Buffalo Bills
18
27
29.5
New York Giants
27.5
27
29.5
Indianapolis Colts
30
25
31
Tampa Bay Buccaneers
22.5
22
32

Table 2: Sacks vs. Baseline Defense Rankings

Correlation: 0.667

Based on the results, the correlation looks high - but is that consistent? 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 Rank to Points-Against Rank Correlation
Year
Sack Rank to Points-Against Rank Correlation
2004
0.509
2011
0.177
2005
0.393
2012
0.542
2006
0.626
2013
0.543
2007
0.444
2014
0.061
2008
0.435
2015
0.546
2009
0.38
2016
0.288
2010
0.545
2017
0.667

Table 3: Sacks vs. Baseline Defense Rankings 2004-2017

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 26 of the 32 teams is just 27 to 43 sacks or less than one per game. Results this close together will lead to correlations with 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
Points-Against Rank
Takeaways
Takeaway Rank
Baltimore Ravens
6
34
1
Jacksonville Jaguars
2
33
2
Detroit Lions
21
32
3
Philadelphia Eagles
4
30
4
Los Angeles Rams
12
28
5
Los Angeles Chargers
3
27
6
Kansas City Chiefs
15
26
7.5
New York Jets
22.5
20
7.5
New Orleans Saints
10
25
9.5
Buffalo Bills
18
25
9.5
Seattle Seahawks
13.5
23
11.5
Washington Redskins
27.5
23
11.5
Pittsburgh Steelers
7
22
13.5
Chicago Bears
9
22
13.5
Carolina Panthers
11
21
16.5
Tennessee Titans
17
21
16.5
Arizona Cardinals
19
21
16.5
Green Bay Packers
26
21
16.5
Dallas Cowboys
13.5
20
20.5
Tampa Bay Buccaneers
22.5
26
20.5
San Francisco 49ers
25
20
20.5
Indianapolis Colts
30
20
20.5
Minnesota Vikings
1
19
23.5
New York Giants
27.5
19
23.5
New England Patriots
5
17
25.5
Denver Broncos
24
17
25.5
Atlanta Falcons
8
16
27.5
Houston Texans
32
16
27.5
Miami Dolphins
29
15
29
Oakland Raiders
20
14
30
Cincinnati Bengals
16
13
31.5
Cleveland Browns
31
13
31.5

Table 4: Turnovers vs. Baseline Defense Rankings

Correlation: 0.438

Okay, that is 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 (23 of 32) have from 17 and 30 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
Points-Against Rank
TAs x 2 + Sacks
TAs x 2 + Sacks Rank
Jacksonville Jaguars
2
121
1
Baltimore Ravens
6
109
2
Los Angeles Rams
12
104
3
Pittsburgh Steelers
7
100
4
Detroit Lions
21
99
5
Philadelphia Eagles
4
98
6
Los Angeles Chargers
3
97
7
New Orleans Saints
10
92
8.5
Carolina Panthers
11
92
8.5
Washington Redskins
27.5
88
10
Chicago Bears
9
86
11
Seattle Seahawks
13.5
85
12.5
Tennessee Titans
17
85
12.5
Kansas City Chiefs
15
83
14
Arizona Cardinals
19
79
15.5
Green Bay Packers
26
79
15.5
Dallas Cowboys
13.5
78
17
Buffalo Bills
18
77
18
New England Patriots
5
76
19
Minnesota Vikings
1
75
20
Tampa Bay Buccaneers
22.5
74
21
Atlanta Falcons
8
71
22
San Francisco 49ers
25
70
23
New York Jets
22.5
68
24
Cincinnati Bengals
16
67
25.5
Denver Broncos
24
67
25.5
New York Giants
27.5
65
27.5
Indianapolis Colts
30
65
27.5
Houston Texans
32
64
29
Miami Dolphins
29
60
30.5
Cleveland Browns
31
60
30.5
Oakland Raiders
20
59
32

Table 5: Turnovers and Sacks vs. Baseline Defense Rankings

Correlation: 0.656

This correlation is starting to head back in the right direction. 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 59 to 121 points), 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 a 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 data from last season once again. Obtaining the two new statistics (4th down turnovers and forced punts), we get the following results:

Team
Points-Against Rank
Takeaways
4th-Down Stops
Forces Punts
TOs x 2 + Punts
Reality Defense Rank
Jacksonville Jaguars
2
33
7
100
180
1
Philadelphia Eagles
4
30
14
83
171
2
Baltimore Ravens
6
34
10
77
165
3
Los Angeles Chargers
3
27
14
79
161
4
Arizona Cardinals
19
21
9
95
155
5
Minnesota Vikings
1
19
14
86
152
6
Denver Broncos
24
17
14
88
150
7
Detroit Lions
21
32
7
71
149
8
Los Angeles Rams
12
28
6
80
148
9
Pittsburgh Steelers
7
22
13
77
147
10.5
Seattle Seahawks
13.5
23
8
85
147
10.5
Kansas City Chiefs
15
26
8
72
140
12
New York Jets
22.5
20
6
87
139
13
Washington Redskins
27.5
23
6
80
138
14
New Orleans Saints
10
25
8
71
137
15.5
Carolina Panthers
11
21
13
69
137
15.5
New York Giants
27.5
19
12
74
136
17
Buffalo Bills
18
25
9
62
130
18
Tennessee Titans
17
21
6
75
129
19
Chicago Bears
9
22
5
74
128
21
Dallas Cowboys
13.5
20
9
70
128
21
Cincinnati Bengals
16
13
10
82
128
21
New England Patriots
5
17
13
67
127
23
Tampa Bay Buccaneers
22.5
26
7
59
125
24
Cleveland Browns
31
13
5
83
119
25.5
Houston Texans
32
16
3
81
119
25.5
San Francisco 49ers
25
20
2
74
118
28
Miami Dolphins
29
15
6
76
118
28
Indianapolis Colts
30
20
7
64
118
28
Green Bay Packers
26
21
2
67
113
30
Atlanta Falcons
8
16
6
66
110
31
Oakland Raiders
20
14
3
70
104
32

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

Correlation: 0.542

The results fall somewhere between sacks (0.667) and takeaways (0.438). Table 7 puts this result in historical context, comparing 2017's Reality Defense correlation to numbers dating back all the way to the 2004 NFL season:

Year
Reality Defense Rank to Points-Against Rank Correlation
Year
Reality Defense Rank to Points-Against Rank Correlation
2004
0.624
2011
0.454
2005
0.666
2012
0.635
2006
0.688
2013
0.649
2007
0.669
2014
0.599
2008
0.617
2015
0.706
2009
0.649
2016
0.633
2010
0.651
2017
0.542

Table 7: Reality Defense vs. Baseline Defense Rankings 2004-2017

Historically, this has been the best correlation between Points Against Rank and defenses, as shown in Table 7 for the past 14 NFL seasons, but it fell a little short this year. This appears to be most attributable to the struggles of Arizona and Denver on offense last season. Both the Cardinals and the Broncos had strong defenses, but the lack of output from both teams on offense likely kept the defenses on the field far too long, which led to more points for the opposition. Had Arizona and Denver finished even 50% closer to their Reality Defense marks, the correlation would be in the 60% range (and the numbers get even better if Detroit had as well). I am not just making excuses here - once in a while, overall team performances do not match their numbers for a span of 16 games. Again, this is why we use historical context, and most of the time Reality Defense is a far superior metric.

Here are the reasons why I believe that Reality Defense is superior when it comes to scoring team defenses for fantasy production. The addition of all turnovers and punts forced has increased the point separation, as it did last season (the range in Table 6 spans from 180 to 104 points), a much bigger span than in Table 5 (59 to 121 points). Since 2004, 12 of the 14 NFL regular seasons had 60% or better correlation using Reality Defense scoring. Last year appears to be closer to an aberration at 54.2% since only one other year (2011, 45.4%) resulted in a correlation under 60% for the past 14 years. Reality Defense proves itself as the best fantasy metric to use. The Reality Defense formula emphasizes getting the ball back to the offense by awarding points for not only turnovers but also forced punts and fourth down stops. These tweaks to the scoring system increase the point range for defenses, allowing the best ones to rise to the top.

So looking at the big picture, 12 of the 13 seasons analyzed had a strong correlation - over 60% - to Points Against, one of the best metrics for defense.

There are additional benefits to this new equation. First, the scores are higher (average score of 8.5 / game) than under the original system (4.9 / 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 2017 average score - by position - of the Top 12 players based upon two common scoring systems:

Position
Non-PPR Points
PPR Points
QB
20.9
20.9
RB1
13.4
17.2
RB2
9.3
11.3
WR1
10.4
16.2
WR2
8.5
12.7
TE
6.8
10.8
PK
8.7
8.7
Def*
8.0
9.7*

*Based upon the new Realistic Team Defense formula.

Table 8: Average 2017 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 24 wide receiver or Top 24 RB (and well below a Top 12 QB). With PPR, the Team Defense declines to a good flex option (RB3, WR3) 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 RB3, WR3, 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 59 and 121 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 (104 to 180, see Table 6) so adding a touchdown reduces the impact to 3-6%. 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