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Defense Analyzer - Week 4

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Defense Analyzer - Week 4

Postby prince_45243 » Tue Sep 27, 2011 10:07 am

Prince's Defense Analyzer - How it's calculated:

Hello all, reviving this column after a year off. Several years ago, I figured out that a defense that allows fewer points is great in real life but really a terrible predictor of how good they are fantasy wise. Same thing goes with being good as a rushing or passing defense. Great at stopping opponents, but not necessarily predictive of fantasy production. The analysis I did was in 2007-2009 and I stopped doing them after that because the results were always the same. The figures are summarized below.

The figure below shows the Points Against (y-axis) versus the average fantasy points produced by the team (average is right around 6.5 points per game). The 'correlation' is only 0.25 (1 is perfect correlation and 0 is absolutely no correlation).
Image

The figure below shows a combination of turnovers and sacks (y-axis) compared to the average fantasy production of the team (x-axis). As you can see, there may be an outlier or two but basically, calculating the turnover and sacks that the team produces highly correlates with the DST fantasy output of the team in question. The r-squared is 0.73 which statistically is excellent!

Image

For the record, turnovers alone had a correlation of 0.59 and sacks had a correlation of 0.30.
I analyzed all different combinations of data including touchdowns, safeties, etcetera and could not improve upon the correlation of 0.73 and all other additional information only reduced the predictive power of the analysis.

So basically, a team that is good at creating turnovers and sacks are more likely to have touchdowns and other things happen and their score is more likely to be better. A team that gives up tons of turnovers and sacks will also be a nice matchup for the defense.

The defense analyzer then looks at each week's matchup, uses updated NFL.com statistics to determine the average weighted value of turnovers and sacks for the defense and their match-up offense and then I sort to provide the list.

In the future, I'll just link to this post rather than continuously posting how the analyzer works.

Thanks,
Prince
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Re: Defense Analyzer - Week 4

Postby prince_45243 » Tue Sep 27, 2011 10:17 am

The following shows the rank, the defending team, their matchup for the week, their average points per week from turnovers and sacks, the matchups average points given up per week for turnovers and sacks and then the sum of those to values in the last column. As described previously, any team may look great if they have a defense or special teams TD but the only predictor of those are increased turnovers and sacks and are otherwise very hard to predict.

Team TO/S Total
1 SDF PHI 7.67 8.33 16.00
2 BAL NYJ 7.67 6.33 14.00
3 ATL SEA 6.33 6.67 13.00
4 CAR CHI 5.67 7.33 13.00
5 DAL DET 7.00 5.67 12.67
6 DET DAL 6.00 6.67 12.67
7 GB DEN 7.33 5.33 12.67
8 NO JAX 4.00 8.67 12.67
9 NYG ARI 7.33 5.33 12.67
10 PHI SDF 6.00 6.33 12.33
11 HOU PIT 5.67 6.33 12.00
12 WAS STL 5.33 6.67 12.00
13 SD MIA 3.00 8.33 11.33
14 SEA ATL 3.67 7.67 11.33
15 CHI CAR 6.00 5.33 11.33
16 MIN KC 5.00 5.67 10.67
17 ARI NYG 5.67 4.67 10.33
18 IND TB 5.67 4.67 10.33
19 NYJ BAL 5.67 4.67 10.33
20 OAK NE 6.00 4.33 10.33
21 BUF CIN 6.00 3.67 9.67
22 TEN CLE 6.00 3.67 9.67
23 MIA SD 2.67 6.67 9.33
24 TB IND 6.00 3.33 9.33
25 CIN BUF 5.00 4.00 9.00
26 CLE TEN 6.33 2.67 9.00
27 KC MIN 5.00 4.00 9.00
28 NE OAK 6.67 2.00 8.67
29 STL WAS 4.00 4.67 8.67
30 JAX NO 3.00 4.00 7.00
31 PIT HOU 2.33 4.67 7.00
32 DEN GB 1.67 3.00 4.67

(SDF = San Francisco)
SF is getting close to 8 points per game from turnovers and sacks and Phillie is giving up 8 points per game in turnovers and sacks. This is a nice matchup for SF. Pittsburgh, unfortunately, has gained only 2 points per game in turnovers and sacks and Houston has been giving up only 4.7 points per game in turnovers and sacks. Slight caveat on NO as a defense, while they have a nice matchup, they haven't so far actually produced that many turnovers and sacks. Another caveat for Dallas who has the vast majority of their points in sacks of which Detroit yields very little.

This data contains only 3 weeks of data and the analyzer works better as the season goes on. I highly recommend not quibbling over a point or two here or there but look at major differences only.

Good luck and hope this helps.
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Re: Defense Analyzer - Week 4

Postby prince_45243 » Tue Sep 27, 2011 10:29 am

The NFL ranks rushing and passing defense based on yards per game. However, from a fantasy perspective, TDs and turnovers are weighted much more than yards are. Thus I created this 'fantasy' defense outlook.

The following is based on 1 point per 25 yards passing, 6 per TD, -2 per turnover. It is listed as fantasy rank, team, NFL rank, score and tough. Score is the average number of points the team is giving up to opposing passers. Tough is how tough a schedule they've had so far this year (what their opponents passing strength is). For example, the NYJ are my top passing defense. Opposing qbs have averaged only 8.2 points per game against them and they have faced the 12th toughest schedule. The NFL ranks the jets as 6th in passing defense based on yards per game only.

Detroit is ranked second on my list and opposing qbs are only averaging 8.9 ppg against them, but they've had the easiest schedule so far this year from passing output (TB, KC and MIN). Washington is truly a great passing defense but are only ranked 15th according to the NFL. But having faced the 6th toughest schedule so far, they have only allowed an average of 11.6 ppg.
PASSING:
TeamRank Scoretough
1 NYJ 6 8.2 12
2 DET 4 8.9 32
3 TEN 2 10.2 13
4 SDF 10 11.4 24
5 WAS 15 11.6 6
6 BAL 17 12.5 11
7 PIT 1 12.6 27
8 IND 18 14.1 23
9 CLE 3 14.2 2
10 NYG 20 14.2 8
11 CIN 5 14.9 26
12 ATL 22 15.8 17
13 JAX 7 15.9 20
14 ARI 25 16.3 7
15 SEA 16 16.4 15
16 HOU 11 17.1 4
17 DAL 12 17.1 18
18 TB 23 17.5 31
19 SD 9 18.8 29
20 CAR 14 18.9 21
21 DEN 13 19.4 10
22 MIN 29 20.0 25
23 BUF 24 20.9 3
24 OAK 28 21.6 16
25 CHI 26 21.8 9
26 PHI 8 22.6 5
27 GB 31 23.0 14
28 STL 19 23.4 22
29 KC 21 23.7 1
30 NE 32 23.7 30
31 NO 27 24.6 19
32 MIA 30 27.1 28

The idea here is if you're between two QBs of relatively equal skill but one is facing an opponent the WAS (15th by NFL, 5th by mine) and the other is facing CAR (14th by NFL but 20th by mine), I would take the one facing CAR. I would typically caution everyone that conventional wisdom says to play the player first, matchup second, all other factors third.

RUSHING
Based on 1 point per 10 yards, 6 per TD, -2 per fumble. SDF=San Francisco. SF has been the toughest team to rush against all year but they've also had the easiest schedule so far facing only SEA, DAL and CIN. Although my highest rank by performance, I would say they are suspect so far. Most of the top 10 teams have had relatively light schedules. The Jets are surprisingly at the bottom of this list and I think undeservedly so. One 70 yd TD run from DMC can really mess with a 3 game statistical curve.

TeamRank Scoretough
1 SDF 13 4.3 32
2 GB 1 6.8 30
3 DAL 2 7.5 23
4 CHI 18 8.9 17
5 BAL 6 9.1 31
6 TEN 8 9.6 24
7 JAX 5 10.4 29
8 CIN 7 11.5 28
9 NYG 15 11.7 8
10 DEN 14 12.0 3
11 CAR 25 12.4 13
12 MIA 16 12.5 11
13 DET 21 12.6 6
14 MIN 4 12.7 15
15 TB 23 12.7 14
16 NO 9 13.1 18
17 SD 19 13.1 7
18 HOU 17 13.2 21
19 CLE 29 13.5 25
20 NE 10 13.8 4
21 PIT 12 13.9 27
22 WAS 11 15.1 20
23 ATL 20 15.2 12
24 SEA 3 15.3 22
25 BUF 24 16.2 1
26 ARI 27 16.3 26
27 PHI 30 16.5 19
28 IND 22 17.3 16
29 OAK 26 17.4 9
30 STL 32 20.8 5
31 KC 28 21.0 10
32 NYJ 31 23.7 2

Please remember that this is total points given to opposing rushers which may be split among several rushers (including the QB).
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Re: Defense Analyzer - Week 4

Postby prince_45243 » Tue Sep 27, 2011 11:32 am

Sorry for the bunching up of numbers, will try to clean that up for future posts.
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Re: Defense Analyzer - Week 4

Postby FU - Football Univ. » Wed Sep 28, 2011 9:00 am

Wow - what an awesome amount of relevant & useful data! Thanks for your work on this! ;-D
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Re: Defense Analyzer - Week 4

Postby rasmusDoh » Wed Sep 28, 2011 10:21 am

Awesome!!
2013 roster (10-man PPR league)

QBs: R. Wilson, Romo
RBs: D. Martin, Sproles, L. Miller, G. Bernard
WRs: R. White, Amendola, Josh Gordon, Edelman, James Jones, Keenan Allen
TEs: Graham
K: Weekly
DEF: Weekly
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Re: Defense Analyzer - Week 4

Postby latraffic » Wed Sep 28, 2011 7:05 pm

Thanks for getting this going again this season. It is a great way to plug in my defense from week-to-week. ;-D
Thank God for Football Season.
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Re: Defense Analyzer - Week 4

Postby Bigins » Thu Sep 29, 2011 3:19 am

Impressive. I have the Jets who play the Ravens. They are #1 in receiving, but #32 in rushing. What a joke. It sounds like Ray Rice is going to eat them alive.

Would you guys look for another defense this week? The problem is if I drop the Jets I risk losing them. They had 24-25 points total the first 2 weeks before last week's 1 point.
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Re: Defense Analyzer - Week 4

Postby prince_45243 » Thu Sep 29, 2011 1:15 pm

Thanks for the feedback. Please don't take this as gospel, it takes a bunch of weeks for the good, the bad and the ugly to get accounted for in the data.

Bigins, Do NOT drop the JETS! That's just crazy talk.

Do Start rushers against the Jets until the numbers start to clearly say otherwise:
The Jets have given up 5 rushing TDs in 3 games. Only the KC Chiefs are as bad as they are in this respect. The Jets are also yielding an average of 137 yards per game on the ground and only St. Louis is worse at 174 ypg. However, there was that ridiculous 70yd TD run by McFadden which skews some of the averages. So yes, so far, opposing rushers have done extremely well against them and honestly, Ray Rice should be started no matter the matchup.

However, those are really statistics geared towards which RB (or passer/WR) to start but are not geared towards predicting how a defense will do in general. Look at the second to top post on defenses and their matchups. The Jets have a solidly in the middle of the pack matchup vs. Baltimore ranked 19th on my list and you'll notice that within 2 points either way goes up to 11th and down to 29th. That list is really if you have more than one defense (which if you have the jets, why would you?) or are floating through the WW for a better matchup than say, NE vs. OAK. The Jets have 7 sacks 7 turnovers and a defensive TD on the year even though they've given up a monster 61 points in the three games. They are second to highest on my fantasy league in performance. Also I did this last week and predicted the jets would struggle vs. Oakland who is just no fun for a defense to play against right now.

Not that I want to denigrate my own post, just saying that even I, the stats guy, play the player first, the matchup second. I just wanted more clarity on matchups than I could tell from points against which is what most of us were using.

Thanks,
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Re: Defense Analyzer - Week 4

Postby audioOtis » Thu Sep 29, 2011 2:00 pm

How accurate have these predictions been the past 3 weeks? I have the pats right now in a 10 league team, but SDF is avail and I am thinking of dropping the pats D and picking them up, based on this. Any advice?
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