I’ll continue posting my odds, though this has not been the best season for them. Jacksonville continued to be best modeled by their median point spread, as opposed to their playoff formula. Philadelphia outperformed any reasonable prediction of their play once Wentz went down.

My system gives an edge to New England. Philadelphia played a tougher schedule but lacks playoff experience by my system. There is no home field in the Superbowl.

Super Bowl Playoff Odds
Home Team Visiting Team Score Diff Win Prob Est. Point Spread
New England Patriots Philadelphia Eagles 0.586 0.642 4.3

Outside of the New England game, all the games were good and exciting, from the final goal line stand by the Eagles, to the win with ten seconds left by the Vikings. The Jacksonville Jaguars are just not well managed by this system. It was easy to see that through the year that they were a boom or bust team. They could win big or lose big, and in the game with the Steelers, they were enough in “win big” mode that the Steelers could not keep up.

Philadelphia won because of their stout defense, a Nick Foles that gave them a AYA of 8.2 for the game, much akin to Carson Wentz’s average.

To remind people, the 2017 worksheet is here, and the methodology is here. The odds for the next round are below.

Conference (NFC/AFC) Playoff Odds
Home Team Visiting Team Score Diff Win Prob Est. Point Spread
Philadelphia Eagles Minnesota Vikings -0.604 0.353 -4.5
New England Patriots Jacksonville Jaguars 1.872 0.867 13.9

The first round is over and in terms of predicting winners, not my best (by my count, 1-2-1, as we had Jax and Bills in a de facto tie). I was pleased that the model got Rams and Atlanta correct, and the Sunday games all came down to the wire. One or two plays and my formal results would have been impressive. Still, back to the predictions for this week.

To add some spice, we will predict results for New Orleans normally, and also as if Drew Brees is elite. Values in parentheses are the elite numbers. With elite status or no, Minnesota is still favored in this data set.

The only home team not favored is Philadelphia. We discussed this in part in this article.

Second Round Playoff Odds
Home Team Visiting Team Score Diff Win Prob Est. Point Spread
Philadelphia Eagles Atlanta Falcons -0.878 0.294 -6.5
Minnesota Vikings New Orleans Saints 1.231 (0.484) 0.774 (0.619) 9.1 (3.6)
New England Patriots Tennessee Titans 1.674 0.842 12.4
Pittsburgh Steelers Jacksonville Jaguars 1.915 0.872 14

Summary: Replacing Wentz with Foles removes about 6.5 points of offense from the Philadelphia Eagles, turning a high flying offense into something very average.

Last night the Atlanta Falcons defeated the LA Rams. Now we’re faced with the prospect of the Falcons playing the Eagles. I have an idiosyncratic playoff model, one I treat as a hobby. It is based on static factors, the three being home field advantage, strength of schedule, and previous playoff experience. And since it values the Eagles as 0.444 and the Falcons as 1.322, the difference is -0.878 (win probability in logits). The inverse logit of -0.878 is 0.294, which is the probability of the Eagles winning, and an estimated point spread would be a 6.5 point advantage for the Falcons.

Another question that a Falcons or Eagles fan might have is how much is Carson Wentz worth as a QB, in points scored? We can use the adjusted yards per attempt stat of Pro Football Reference to estimate this, and also to estimate how much Carson Wentz is better than Foles. We have made these kinds of analyses before for Matt Ryan and Peyton Manning.

Pro Football Reference says that Carson Wentz has a AYA of 8.3 yards per attempt. Nick Foles has a AYA of 5.4. Now lets calculate the overall AYA for every pass thrown in the NFL. Stats are from Pro Football Reference.

(114870 yards + 20*741 TDs – 45*430 Ints) / 17488 Attempts
(114870 yards + 14820 TD “yards” – 19350 Int “yards”) / 117488 Attempts
110340 net yards / 17488 yards
6.31 yards per attempt to three significant digits

So about 6.3 yards per attempt. Carson Wentz is 2 yards per attempt better than the average. Nick Foles is 0.9 yards less than the average. The magic number is 2.25 which converts yards per attempt to points scored per thirty passes. So Carson, compared to Foles, is worth 2.9 * 2.25 = 6.5 points per game more than Foles, and 4.5 points more than the average NFL quarterback.

This doesn’t completely encompass Carson Wentz’s value, as according to ESPN
‘s QBR stat
, he account for 10 expected points on the ground in 13 games, so he nets about 0.8 points a game on the ground as well.

Now, back to some traditional stats. The offensive SRS assigned to Philadelphia by PFR is 7.0 with a defensive SRS of 2.5. If Carson Wentz is worth between 6.5 and 7.3 points per game, then it reduces Philadelphia’s offense to something very average, about 0.5 to -0.3. That high flying offense is almost completely transformed by the loss of their quarterback into an average offense.

Note: logits are to probabilities as logarithms are to multiplication. Rather than multiplying probabilities and using transitive rules, you just add the logits and convert back. Logarithms allow you to add logarithms of numbers rather than multiplying them.

The teams in the 2016 Championship are Atlanta and New England, and my system this year slightly favors Atlanta, given the same assumptions that we used initially. Atlanta is selected as the “home team”, though no home team is used in any of the final calculations.

Odds are presented from the home team’s point of view:

NFL Championship Round Playoff Odds
Home Team Visiting Team Score Diff Win Prob Est. Point Spread
Atlanta Falcons New England Patriots 0.092 0.523 0.6

We present a series of alternate calculations below. They are based on — what if Atlanta should be treated as a team with playoff experience, then median point spread, then Pythagoreans, and then the Simple Ranking system.

ATL – NE Alternate Calculations
Odds Method Score Diff Win Prob Est. Point Spread
ATL has playoff experience 0.839 0.698 6.2
Median Point Spread -0.68 0.34 -5.0
Pythagoreans -0.92 0.29 -6.8
Simple Ranking -0.11 0.47 -0.8

There is nothing consistent in any of the ratings methods. Median point spreads, when pumped into a logistic regression, have less correlation than Pythagorean, though in both cases, the confidence intervals are on the order of 0.15, as opposed to less than 0.05. Medians and Pythagoreans suggest New England has a large advantage, Simple Rankings say the game will be close, too close to bet. So two claim close games, toss ups more or less, one suggests an easy Atlanta victory, and the others suggest a substantial Patriots margin.

Last week was not the best for the “system”. That said, a system that wins all the time probably isn’t a system at all, but merely wishful thinking.

For the third week of the 2016 playoffs, odds are presented from the home team’s point of view:

Conference Round Playoff Odds
Home Team Visiting Team Score Diff Win Prob Est. Point Spread
Atlenta Falcons Green Bay Packers -0.079 0.480 -0.6
New England Patriots Pittsburgh Steelers -0.219 0.445 -1.6

The odds in Atlanta -GB are too close to call. My system would not suggest betting that game. My system favors Pittsburgh. As stated previously, New England played a weak schedule and that’s a major factor in our rankings. Both games are seen as close.

My system scored 4-0 in terms of predicting wins, but at this point the teams are better and the games are closer. Detroit, I believe, would have been a closer game had Matthew Stafford not been injured. His receiver dropped balls and Seattle was the beneficiary of some incredible pass receptions. That said, we’re into the second round and so will present the second round odds, as determined by the 2 year PPX formula. Odds are presented from the home team’s point of view:

Second Round Playoff Odds
Home Team Visiting Team Score Diff Win Prob Est. Point Spread
Dallas Cowboys Green Bay Packers 0.569 0.639 4.2
Atlanta Falcons Seattle Seahawks 0.475 0.617 3.5
New England Patriots Houston Texans -0.247 0.439 -1.8
Kansas City Chiefs Pittsburgh Steelers 0.806 0.691 6.0

I will note that this system does not favor the New England Patriots, because their -2.65 point Strength of Schedule weighs against them. Both Kansas City or Pittsburgh would be favored in the next round, should New England win. But it’s not a large difference, and Tom Brady is having a magical season. We’ll see.

It is certainly reasonable to argue that Dallas only has playoff experience to 2014 and Green Bay has 2015 experience, and thus the 1 Year PPX formula should be used. We did calculate those odds, as well as odds generated by a median point spread and also Pythagorean expectations and the Simple Ranking System. In all three cases we used the stock 3 point home field advantage.

Dallas Green Bay Alternate Calculations
Odds Method Score Diff Win Prob Est. Point Spread
New 1 Year PPX Formula -0.113 0.47 -0.8
Median Point Spread 0.47 0.62 3.5
Pythagoreans 1.1 0.75 8.1
Simple Ranking 0.96 0.72 7.1

Using a 1 year formula, Dallas-GB would be too close to call. All other formulas favor Dallas. Medians would have given essentially the same odds as the two year PPX, had we chosen to honor a 3.8 point HFA, as is calculated for playoff teams. Both Pythagoreans and SRS give Dallas about a touchdown advantage.