NFL playoff races and other musings

Here they are.

Once the playoff teams are finalized, I’ll do a year in reveiw post and a preview of improvements on slate for next season.

Percent probability of team finishing in each place within the division

AFC EAST

AFC NORTH

AFC SOUTH

AFC WEST

NFC EAST

NFC NORTH

NFC SOUTH

NFC WEST

Generated: Tue Dec 26 00:38:01 EST 2006

AFC Percent Probability Playoff Seeding

NFC Percent Probability Playoff Seeding

Generated: Tue Dec 26 00:38:01 EST 2006

The end is near, the end is near!

 I’ll post the DVOA comparison graph tomorrow. Should be interesting.

Percent probability of team finishing in each place within the division

AFC EAST

AFC NORTH

AFC SOUTH

AFC WEST

NFC EAST

NFC NORTH

NFC SOUTH

NFC WEST

Generated: Tue Dec 19 00:30:23 EST 2006

AFC Percent Probability Playoff Seeding

NFC Percent Probability Playoff Seeding

Generated: Tue Dec 19 00:30:23 EST 2006

Here are this week’s forecasts.

Percent probability of team finishing in each place within the division

AFC EAST

AFC NORTH

AFC SOUTH

AFC WEST

NFC EAST

NFC NORTH

NFC SOUTH

NFC WEST

Generated: Tue Dec 12 00:17:35 EST 2006

AFC Percent Probability Playoff Seeding

NFC Percent Probability Playoff Seeding

Generated: Tue Dec 12 00:17:35 EST 2006

I’ve prepared the comparison between playoff predictions based on DVOA power ratings and NFL-Forecast playoff predictions in graphical time-series form , from week 9 through week 13. The filled circles represent DVOA predictions while the open circles represent my predictions. Hopefully the team-based color coding that I used is self explanatory. I’ll include the Week 13 DVOA ratings as soon as Mike Harris posts them.

The first set of graphs shows the division races (I’ve shown only teams that have had a significant chance since week 9). All 8 division races appear to be converging to selecting a champion, using both the DVOA and NFL-Forecast projections. DVOA ratings did significantly better in predicting the AFC West race, recognizing the superiority of the Chargers compared to the Broncos. In the NFC East race, my software had greater misplaced confidence in the Giants than DVOA, but transferred this misplaced confidence to the Eagles. Neither system really picked out the Cowboys as the division winner significantly better that the other. In the rest of the races, the predictions were comparable, with DVOA converging to apparent division winners slightly faster than NFL-forecast, with the exception of the NFC West race. My system still holds a bit of hope for the Jets, to eek out the AFC East title, while the DVOA has declared the race all but over. In contrast, the Wild Card races are not converging, with only 4 weeks remaining in the season.

The Wild Card race this year appears to be a white noise process, with team’s fortunes rising and falling on a weekly basis. The early front runners as predicted by both systems, the Broncos and Giants, have lost much of their lead. It will be interesting to see if either system outperforms the other in the WC race, but the lack of convergence would seem to indicate that any better performance of one system over the other would be attributable to luck rather than reproducible predictive ability. Nevertheless, forecasts like these during dynamic non-converging playoff races do help quantify the race if it is understood to be a snapshot in time.

Only preliminary conclusions can be made, since the playoff races are not over yet, and even when they are, a single season is still a pretty small data set. But this playoff forecasting exercise appears to be pointing to a small but significant advantage of DVOA compared to win-only systems in predicting future results.

Here are this week’s playoff predictions. If you’re a fan of one of the five 7-5 AFC teams or one of the four 6-6 NFC teams, you’ll want to try out the software this week if you haven’t already done so. There are lots and lots of scenarios to analyze and my software automatically analyzes all the tiebreakers for you. It’s playoff madness!

Tomorrow, I’ll post a graphical week-by-week comparison of my forecasts and the DVOA forecasts, starting from week 9 until now.

Percent probability of team finishing in each place within the division

AFC EAST

AFC NORTH

AFC SOUTH

AFC WEST

NFC EAST

NFC NORTH

NFC SOUTH

NFC WEST

Generated: Tue Dec 05 00:20:05 EST 2006

AFC Percent Probability Playoff Seeding

NFC Percent Probability Playoff Seeding

Generated: Tue Dec 05 00:20:05 EST 2006

Here is this week’s comparison Mike Harris’ playoff predictions  based on DVOA power ratings and my playoff forecasts. The two forecasts are really starting to converge.

 Edited to correct data entry error.

                      Division Championship   Playoff Odds
Team              DVOA       NFL-F           DVOA       NFL-F
NewEngland    98.70%     88.64        99.30%     94.46
NYJets            1.00%       11.04       12.60%     35.8
Miami              0.10%       0.14          0.90%       2.74
Buffalo            0.00%       0.18          0.60%       4.82
                                                                         
                      Division Championship   Playoff Odds
Team              DVOA       NFL-F           DVOA       NFL-F
Indianapolis     99.80%     99.94        99.9%     99.98
Jacksonville     0.10%       0.06         26.60%    14.84
Houston           0.00%       0             0.00%     0.02
Tennessee       0.00%       0              0.00%      0.1
                                                                         
                      Division Championship   Playoff Odds
Team              DVOA       NFL-F           DVOA       NFL-F
Baltimore         99.30%     95.08       99.90%     98.1
Cincinnati        0.60%       4.9          27.20%     33.12
Pittsburgh        0.00%       0.02        0.10%       0.22
Cleveland        0.00%       0             0.00%       0
                                                                         
                      Division Championship   Playoff Odds
Team              DVOA       NFL-F           DVOA       NFL-F
SanDiego        92.90%     80.76        99.70%     98.32
Denver            4.40%       11.44       74.20%     70.56
KansasCity      2.60%       7.8           55.70%     46.92
Oakland           0.00%       0               0.00%       0
                                                                         
                      Division Championship   Playoff Odds
Team              DVOA       NFL-F           DVOA       NFL-F
NYGiants         19.80%     24.22       75.60%     64.38
Philadelphia     4.50%       3.24         40.70%     17.26
Dallas              75.60%     72.06       97.80%     91.4
Washington     0.00%       0.48           1.70%       5.48
                                                                         
                      Division Championship   Playoff Odds
Team              DVOA       NFL-F           DVOA       NFL-F
Chicago          100.00%   99.94        100.00%   99.98
GreenBay        0.00%       0                2.80%     1.18
Minnesota        0.00%       0.06          11.60%   18.04
Detroit             0.00%       0               0.00%       0
                                                                         
                      Division Championship               Playoff Odds    
Team              DVOA       NFL-F           DVOA       NFL-F
NewOrleans     75.10%     67.62       92.00%     89.06
Carolina          24.50%     30.66       57.90%     61.6
Atlanta             30.00%     1.72        2.30%     10.48 
TampaBay       0.00%       0              0.00%       0.04
                                                                         
                      Division Championship               Playoff Odds    
Team              DVOA       NFL-F           DVOA       NFL-F
Seattle             83.70%     79.98      88.00%     89.34.96
SanFrancisco  4.10%       14.72          6.00%     25.44
StLouis            12.10%     5.3          22.90%     26.32
Arizona           0.00%       0               0.00%       0.08

Things crystalized quite a bit in week 12. We now have a very good idea of 5 of the playoff teams in each conference, although Denver and the Giants are still a little squishy, both in their computer generated playoff odds and in their on the field play. So in each conference we have one, maybe two, playoff spots up from grabs. Those last slots probably won’t be firmed up until the last week of the season. Plus the teams that are likely playoff qualifiers are still slugging it out for seeding positions that yield home field advantage and first round byes.

Edited to correct data entry error 

Percent probability of team finishing in each place within the division

AFC EAST

AFC NORTH

AFC SOUTH

AFC WEST

NFC EAST

NFC NORTH

NFC SOUTH

NFC WEST

Generated: Mon Dec 04 21:24:30 EST 2006

AFC Percent Probability Playoff Seeding

NFC Percent Probability Playoff Seeding

Generated: Mon Dec 04 21:24:29 EST 2006

I’m going to do these comparisons between Mike Harris’ playoff predictions  based on DVOA power ratings and my playoff forecasts for the remainder of the season. I think they will provide a basis for determining the predictive value of the DVOA based power ratings in comparison to power ratings based on wins and losses only.

 I’ve decided to use the playoff predictions based on the standard DVOA, rather than the Donovan McNabb adjusted version. Every team suffers injuries, and I don’t think you can consider an injury to one player in the whole league on an ad hoc basis. I also discovered that in week 10 I had mistakenly entered a Viking win over Green Bay, that was making my projections for the Vikings overly optimistic and to a lesser extent, penalizing the chances of the Packers. I fixed that in this weeks projections, but I haven’t gone back and fixed week 10 projections.

                         Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
NewEngland      97.80%      89.76           98.40%      94.18
NYJets              1.90%       10                8.40%       28.48
Miami               0.10%       0.14             0.40%       1.32
Buffalo              0.00%       0.1               0.30%       2.36
                                                                             
                        Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
Indianapolis       95.70%      99.34           99.50%      99.94
Jacksonville       4.20%       0.66             59.20%      32.16
Houston            0.00%       0                  0.00%       0.14
Tennessee        0.00%       0                  0.00%       0.02
                                                                             
                        Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
Baltimore          98.50%      96.64           99.10%      98
Cincinnati         1.10%       2.62             10.20%      18.94
Pittsburgh         0.30%       0.74             1.80%       1.76
Cleveland          0.00%       0                  0.00%       0.24
                                                                             
                        Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
SanDiego          87.00%      62.6             99.60%      96.82
Denver              11.80%      31.96           88.60%      90.72
KansasCity       1.10%       5.44             33.70%      34.92
Oakland            0.00%       0                  0.00%       0
                                                                             
                        Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
NYGiants          43.20%      62.2             89.40%      82.2
Philadelphia      8.00%       29.46           54.90%      27.92
Dallas               48.60%      8.34             93.60%      61.42
Washington       0.00%       0                  0.50%       0.54
                                                                             
                        Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
Chicago            100.00%    99.94           100.00%    99.98
GreenBay         0.00%       0.04             7.50%       2.72
Minnesota         0.00%       0.02             4.60%       14.9
Detroit              0.00%       0                  0.00%       0.02
                                                                             
                        Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
NewOrleans       51.50%      43.04           70.20%      75.84
Carolina            44.60%      43.84           62.50%      70.46
Atlanta              3.80%       13.12           7.60%       29.66
TampaBay        0.00%       0                  0.00%       0.42
                                                                             
                        Division Championship   Playoff Odds
Team                DVOA       NFL-F          DVOA       NFL-F
Seattle              69.60%      72.32           72.50%      82.16
SanFrancisco    11.00%      21.64           12.60%      33.42
StLouis             19.20%      6.04             23.40%      18.34
Arizona             0.00%       0                  0.00%       0

 Edited to fix a week 10 data entry error.

 Not much changed this week in the AFC.

 In the NFC, everything has opened up quite a bit. Tiebreakers will play a huge role in the NFC race. If you are a fan of one of these teams, I encourage you to use the software on my main site to do scenario analysis.

If there is a particular analysis you’d like to see leave a comment and I’ll see what I can do.

Percent probability of team finishing in each place within the division

AFC EAST

AFC NORTH

AFC SOUTH

AFC WEST

NFC EAST

NFC NORTH

NFC SOUTH

NFC WEST

Generated: Tue Nov 21 18:36:34 EST 2006

AFC Percent Probability Playoff Seeding

NFC Percent Probability Playoff Seeding

Generated: Tue Nov 21 18:36:33 EST 2006

Football Outsiders (or more precisely, FO reader Mike Harris) has started doing playoff prediction simulations similar to those I have been doing here, except based on the DVOA power ratings.  Football Outsiders uses extensive play-by-play data for their power ratings. I use just the opposite approach, using only the out come of each game (won-loss, not score) and where the game was played as the basis of my power ratings. I am a frequent reader of Football Outsiders and have a lot of respect for their work. I’ve considered adding DVOA power ratings as an alternate power ranking scheme to my software, and building a win prediction model from the DVOA ratings, but the job thing has kept me pretty busy this fall. So I’m glad Mr. Harris has taken that off my to do list.

I thought it would be worthwhile to publish a side by side comparion. It is very interesting how closely the predictions based on the two power ranking methods compare, although there are some very significant differences. The difference in prediction for the Denver-SD division race is particularly interesting. SD is clearly better based on DVOA; watching the two teams play it is easy to see why. Denver seldom gets any style points for the games they have won this season. Yet my power rating system is more impressed by Denver because they have beaten three team with winning records (New England, Baltimore, Kansas City) while San Diego hasn’t beaten any. And that is the thing about Denver, they consistently find a way to win. San Diego on the other hand found a way to lose to the Ravens, a game they probably should have won. To some extent, I think that wins and losses captures some of the intangibles that DVOA or other statistical measures aren’t able to quantify. I’m not arguing that W-L is a better predictor of future wins than DVOA; rather, I think the two approaches are complementary. Furthermore, I feel a little more comfortable with some of the DVOA-based NFC predictions. In particular, Minnesota is looking very shaky after their fast start and San Francisco’s high power rating this week is an anomaly due to the large variances in my power ratings. The SF bug is something that I know how to fix, but don’t have time to code this season. On the other hand, it will be interesting to see if Dallas and Philadelphia do as well in the playoff race as projected by DVOA.

Very cool, Mike Harris and Football Outsiders, and welcome to the playoff forecasting business.