Ahoy folks, Tom here with the “Bonfire of the Vanities” edition of this feature. Lots of new stuff to mull over this week, given the changes to the tiebreaker system.
As you might expect, the rankings have undergone a significant shuffle this week. Three matchups looked like pretty significant upsets:
- Philadelphia’s loss to Oakland;
- Cincinnati’s loss to Houston; and,
- NY Jets’ loss to Buffalo.
The overall effect on the system of team rankings was substantial. For the last two weeks, we’ve only had two teams move 10+ spots. This week we had four: Houston, Cincinnati, San Diego, and Green Bay. All four of those big shifts, as Kenneth explained, were based on the results of the Houston-Cincinnati game.
The two graphs below show the raw number of rank changes between Week 5 and Week 6 (“Stability”), and the statistical measure of the dispersion of rank changes (“Variance”). Both show a big spike this week.
Pick Confidence for Week 7
Looking at pick confidence last week didn’t go very well. Usually, the low confidence picks have about twice the incorrect results than the high confidence picks. But last week, the outcome was reversed, with Philadelphia, Cincinnati, and the NY Jets all falling to their low-ranked opponents. Certainly some or all of these can be explained away as ‘flukes,’ but a dismissive approach to problems with one’s own model doesn’t lead to a better model.
Fortunately, over the past few weeks TT has been discussing and now implementing a new tiebreaker model. Part of the implementation has been to get rid of the old BeatPower numbers and replace them with a new set of numbers—EdgePower. TT has backtested this scheme as a tiebreaking method and found that it is more accurate when applied to the last few seasons worth of data. Hopefully, using the EdgePower numbers will give us slightly more sensitive comparisons between teams when trying to determine the confidence that the Beatpaths system has in a given matchup’s outcome.
So without further ado, here are this week’s confidence rankings of the Week 7 picks:
(out of 100)
(predicted winner – predicted loser)
|New England-Tampa Bay||63.52||75.68-12.16||✓|
|San Diego-Kansas City||20.95||56.76-35.81||✓|
One aspect of the new system that is immediately apparent is the much larger number of low confidence games. The contrast between team strengths, using EdgePower numbers, is much less stark. My intuition is that over the course of the season, as the graph gets more and more connected, the EdgePower of the teams at the top and bottom will begin to diverge more clearly from the middling or inconsistent teams.
Only two games are given a high confidence pick by the system: New England over Tampa, and Indianapolis over St. Louis. The two bottom games stand out to me as well. Just like last week, we have a zero-confidence game between Buffalo and Carolina. And the very close call the system is making between the NY Jets and Oakland is a bit shocking at first, but I suppose since Russell had a not-terrible day against the Eagles D, whereas Sanchez did his best Delhomme imitation last Sunday, I can see how such a close pick can be rationalized.
I like having a new and updated EdgePower system, but I am sensitive to the fact that it’s much less ‘confident’ about making picks now. Making more qualified predictions is not necessarily making better predictions. However, we’ll see how it goes over the course of the season, and get a sense for what exactly constitutes a high confidence score using the new numbers. And, after all, BeatPaths was not built to be predictive so much as it was built to be descriptive. So confidence rankings for picks remains, as always, just a fun side-project.
I’ll be back on game-day to fill in the correct and incorrect results of the picks.
Who’s Flukey Now?
Last week I was able to start looking at the retroactive records of several teams, once we got our first beatloop. Because Beatpaths simply removed any games involved in a beatloop from the system, it introduces some ambiguity into the rankings. So the idea here is to look and see which past games don’t make sense given each team’s current ranking. Maybe this will give us some insight into inconsistent teams or fluke games.
Here are the teams involved in beatloops this week. The record beside each team is not its win-loss record, but the Beatpaths record at ‘picking’ each team’s past matchups, and the results that are inconsistent with their current rank.
- Cincinnati (3-3): wins over Green Bay, Baltimore, and Pittsburgh.
- NY Jets (3-3): wins over Houston, New England; loss to Miami.
- San Diego (3-2): losses to Baltimore, and Pittsburgh.
- Green Bay (3-2): win over Chicago, loss to Cincinnati.
- Houston (4-2): losses to NY Jets, and Jacksonville.
- Baltimore (4-2): win over San Diego; loss to Cincinnati.
- Pittsburgh (4-2): win over San Diego; loss to Cincinnati.
- Jacksonville (4-2): win over Houston, loss to Seattle.
- Chicago (4-1): loss to Green Bay.
- New England (5-1): loss to NY Jets.
- Miami (5-1): win over the NY Jets.
- Seattle (5-1): win over Jacksonville
- Buffalo (5-1): win over NY Jets
For all the other teams not listed here, Beatpaths has a perfect 6-0 or 5-0 record in ‘predicting’ their past record, given their current rank.
As you can see, the two most difficult teams to place are Cincinnati and the NY Jets. You can get an intuitive sense for their inconsistency by looking back at the Week 6 rankings, and seeing the range of possible ranks Cincinnati and the NY Jets could have and remain consistent with the graph. They could be top teams, they could be terrible teams, or they could be both and we might just never know which will show up on game day.