Roundup 11/23/2013

Using the logit equation on SRS to estimate game winner probabilities.

Bricklayers vs. Gladiators in baseball.

Chase ranks teams according to how many teams have had their best game against them.

Is Peyton on pace to break the TD record? (O.P.) Is Eli on pace to break the interception record?

How big have college players grown?

Do teams need a Stat-Whisperer?(gated) Tango's discussion.

Which teams have started the most QBs since '99?

Repeatability and survivorship bias in the NHL. Applies to all sports. Helmet-knock Tango.

Brady vs. Manning: Who Really Has the Upper Hand?

There are lots of different ways to measure who truly has "the upper hand" in the Tom Brady-Peyton Manning rivalry.  Brady supporters will cite his teams' 9-4 head-to-head record as the decisive edge, while the Manning camp may point out that their quarterback has the better stats over the 13 meetings.  These arguments dovetail with each quarterback's general reputation—Brady as the winner, Manning as the stat-sheet stuffer.

Of course, neither Brady nor Manning play defense, so a "head-to-head" comparison is a bit short-sighted to begin with.  Jake Plummer was 2-0 against Brady, and Jay Fiedler put up better numbers in his four head-to-head matchups against Manning.  Somehow, I doubt a "Fiedler vs. Manning" post would generate much debate.

So how do we begin to truly evaluate which quarterback has performed better in 13 Manning vs. Brady games?  Well, let's start by looking at their WPA, EPA and passing success rate (SR) during each of their games:

Playoff Projections - Week 11

All of the numbers below come from Chris Cox at NFL-forecast.com. His app uses the win probabilities from the ANS team efficiency model to run a Monte Carlo simulation of the remaining NFL games thousands of times. Based on current records, our estimates of team strength, and knowledge of the NFL's tie breaking procedures we can come up with some pretty interesting predictions of how each team will fare come the end of the season. If you want to use a different model or just fiddle with the numbers by hand, go ahead and download the app yourself.

San Francisco and Green Bay fall

After week 8, we gave the 49ers a 94% chance of making the playoffs. Two losses have contributed to their current odds of 44%, but they are also being squeezed out of wild card contention by the success of their peers. The simultaneous win streaks by the Panthers and Cardinals led to jumps in playoff probability of 41% and 26%, respectively, in that 3 week span. At this point, their best hope is sneaking in to that 6th NFC slot.

Green Bay's third straight loss has put them in a similar situation. What was an 83% chance 3 weeks ago is now just 33%. They have a relatively easy game against the Vikings this week before the crucial Thanksgiving match up versus the Lions.

Game Probabilities - Week 12

Game probabilities for week 12 are available at the New York Times. This week I look at the Jets' strange Pythagorean record.

...This season the Jets are doing their best to defy James, Pythagoras and their formulas. They have scored 183 points and allowed 268 on their way to a 5-5 record. That’s a net point difference of -85, which is second worst in the league, topping only the Jaguars. According to the Pythagorean expectation, the Jets should have about a .265 winning percentage, good for a 3-7 record or perhaps 2-8...

Podcast Episode 9 - Brian Burke

Brian Burke is back to discuss momentum, clock management and topics from his weekly roundups. In his recent post on momentum, Brian used three different methods to investigate whether momentum is a measurable phenomenon in NFL games. Dave and Brian discuss why momentum is such a popular concept and hypothesize why coaches and analysts seem to rely so heavily on the idea. They also discuss Brian’s article on clock management, and why it’s unlikely that truly non-zero sum scenarios exist in a football game. They finish up the show with a "rapid fire roundup" of some interesting articles and analysis from around the web.

Subscribe on iTunes and Stitcher

Momentum Part 2: The Effect of Momentum-Swinging Events on Game Outcomes

Recently I tried to detect the existence of momentum within an NFL game. I examined drive success based on how 'momentous' the manner in which the offense gained possession. Admittedly, that analysis only measures one aspect of momentum. In this post, I'll take the analysis a step further and look at how a team's chances of winning are affected following several momentum-swinging types of events. This approach examines the potential effect of momentum on the entire remaining part of a game, not just on the subsequent drive.

Like the previous analysis, I relied on how possession was obtained as an indication of a momentum-swing. For all drives from 1999-2013 ( through week 8), I compared a team's expected chances of winning (based on time, score, field position, down and distance) with how often that team actually won. I divided the data among three categories: possession obtained following a momentous play, possession obtained following a turnover on downs, and possession obtained following a non-momentous play.

Momentous obtainment includes fumble recoveries, interceptions, muffed punts, blocked kicks, and blocked field goals. I excluded missed field goals from the analysis because it was unclear to me how momentous they are. They are often thought of as big momentum changing events in close games but are too common (almost 20% of all kicks) to truly be momentous.

Team Efficiency Rankings: Week 11 [Corrected]

[Edit: My personal apologies for a bug since 2 weeks ago that penalized teams who had already had their byes. (I believe) it's been fixed, and I've made the corrections to the rankings below. -B.B.]

Strength of schedule is a fickle variable, one that should tell us more about a particular opponent but really does not.  Though this formula does account for S.O.S, that's not always the best indicator of whether or not a team has faced "legitimate" competition.

Despite what Bill Parcells may have you believe, a team is not always what their record says they are.  They are often a flawed representation of late-game variance and fluky injuries, especially when you're splitting hairs among closely contested teams.  That's how you end up with Tampa Bay being the 20th-ranked team in Football Outsiders' DVOA despite entering the week a single win.

Still, there are instances where a team shows some pretty alarming splits among the haves and have-nots.  In the case of one likely playoff team, that makes for some troubling signs going forward.

Newton's Football

Forbes writer Allen St.John and materials scientist Ainissa Ramirez recently wrote a book titled Newton's Football on various intersections between science and our favorite sport. It's right up ANS' alley. Allen has an article at Forbes with an excerpt from the book:

"The theory that coaches were purely motivated by job security and didn’t want to go against the conventional wisdom, that didn’t quite satisfy me," says Brian Burke of Advanced NFL Stats. Week in and week out, Burke analyzed games and saw evidence that NFL coaches were costing their teams yardage, 1st downs, and, ultimately, games because of the questionable decisions they were making. He further noticed that those coaches almost invariably erred on the side of caution. But why?...

"In terms of team building, risk taking is good," Burke argues. He notes that in any given year the average NFL team enters a season with a Bayesian prior expectation of winning a Super Bowl that’s 1 in 32. "You’re a 31–1 underdog. You want to take chances," Burke explains. "It’s okay to miss the playoffs and win five games instead of seven. It doesn’t hurt you that much. But teams are very conservative. They'd rather win a few more games and avoid having a terrible record."