Play-by-Play Data Update

The NFL play-by-play data set has been updated through week 12 of the 2013 season. It's available here, or via the main drop-down menu under the About tab. Nearly every NFL play since 2002 is included for your research purposes. Happy crunching.

The 2013 Eagles and the Criteria of a Super Bowl Contender

It's no secret that scoring has risen in the NFL.  2013 is on pace to be the highest-scoring season in league history, as teams are averaging 23.3 points per game.  After sticking around the 18-20 point range from 1990 to the early 2000s, point increases have experienced an accelerated growth as a consequence of the league's emphasis to liberate offenses.

And yet, there remains a perception that flashy high-scoring teams are only capable of regular-season success, possessing some ambiguous inherent flaw that makes them go kaput in January.  Recent examples include the 2010 Falcons, 2010 Patriots, 2011 Packers and 2012 Broncos.  All these squads represent high-flying number one seeds whose pass-happy offenses flamed out in stunning fashion during a Divisional Round upset.

Playoff Projections - Week 12

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.

Week 12's biggest movers

Capitalizing on Washington's anemic passing performance, San Francisco ended its losing streak. Because Seattle has the West essentially wrapped up, the Cardinals and the loser of the South divisional race are San Francisco's primary rivals at this point. Until recently they also had to worry about the second place team in the north, but the top 3 teams in the division all going winless last week effectively ended that concern. Based on all this, the 49ers jumped 23% to a 67% playoff probability.

Win Probability Calculator Upgrade - New OT Rules

After the MIN-GB overtime game Sunday, you may have stopped by the Win Probability Calculator tool to see what GB should have done on 4th down on the goal line on their first possession. As luck would have it, I rolled out a big upgrade to the calculator just the night before that incorporates the three various game states in overtime.

Under the 'Period' input, there are the 4 quarters, plus 3 overtime states, corresponding to:

-'First possession', in which a team can score a TD to win or a FG to begin...
-'Down by three', in which a team has all 4 downs to move down the field to win with a TD or match the FG to begin...
-'Sudden death', which begins upon any change of possession with a tie score.

The previous version of the calculator still relied on the old pure-sudden-death overtime format. With so few examples to test against, I'm sure there are a few bugs or discontinuities waiting to surprise us, so please note any discrepancies in the comments here. But remember that not all unexpected results are errors--The new format does have its quirks.

The new overtime model has already been working for the WP graphs and team/player stats. Soon I'll roll it out for the 4th Down Calculator too. And more big upgrades to the WP calculator tool are on their way.

Game Probabilities - Week 13

Game probabilities for week 13 are available at the New York Times. This week I look at Aaron Rodgers's value to the Packers.

...The model used here to produce the game probabilities is a “parametric” model, meaning its inputs are parameters that can be varied easily. That’s obviously a good thing, as team statistics certainly vary from week to week. It’s also handy because those parameters can be manually adjusted to account for injuries and just to play what-if...

By replacing Rodgers’s numbers with Flynn’s, and holding all other factors as is, we can get a rough idea of how the game probability should change. Unsurprisingly, the numbers would now heavily favor Detroit...

Team Efficiency Rankings: Week 12

The old adage that a championship team must "run the ball and stop the run" is out of date, as this site has expounded in great detail.  If it's true that today's NFL is a passing league (spoiler: it is), then the exact opposite of the original saying must be true, right?  It seems logical to assume that in order to win the Super Bowl, a team must be able to pass and stop the pass.

While the first part of that formula is likely true, the second part is a bit more ambiguous.  Super Bowl XLVI pitted two below-average pass defenses in the Giants and Patriots, but the year before, the Packers and Steelers met for the title with two of the three best pass defenses in the league.

Those are only two examples, but there's nothing that tells us that a super pass defense is absolutely essential to a Super Bowl champion or contender.  Of course, there's no denying that it helps—last year, only the Patriots, Redskins and Colts made the postseason with a negative pass D EPA.

Therefore, if we consider good pass defense an important but not indispensable quality, that bodes well for a contender who, despite this past weekend's results, is showing quiet improvement in that area.

Was Belichick Right to Take the Wind in OT?

I was surprised when Bill Belichick chose to take the second possession (and risk no possessions) in OT against Peyton Manning and a team that had scored 31 points in four quarters. Although the new OT format mitigates the advantage of the team with first possession, it's still there to the tune of about 56% to 44%.

The advantage of wind must have felt fairly strong to Belichick. His team captains thought he was crazy. At the time, it was impossible to tell from the comfort of my sofa how bad the wind was, but I was curious if we could see the effect statistically.

Podcast Episode 10 - David Romer

David Romer, professor of economics at UC Berkeley, is on the podcast this week to discuss why coaches should be more aggressive on fourth down. David is the author of "Do Firms Maximize? Evidence From Professional Football" and in this interview, he explains his novel approach to analyzing fourth down decision-making. He outlines reasons why coaches are incentivized to make sub-optimal choices and how they can improve their team’s chances of winning by following his advice.

Professor Romer explains why "critical probabilities" are important, and why the "dead zone" on the field presents unique choices for an offense stalled on fourth down. He also tells the story of how after hearing Bill Belichick's critique that his paper didn’t account for the existence of momentum, he amended the writing to include an examination of why momentum in the NFL does not have a measurable effect on game results. For more on the professor's paper, check out the following links:

- Brian Burke’s review. In his response, Brian explains why the professor’s research may actually underestimate the effects of his proposed offensive strategy. [Edit: Prof. Romer set me straight a few yrs back. I overlooked that the paper makes the same point I made. -Brian]

- New York Times coverage

- ESPN the Magazine essay by Michael Lewis

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