Big Changes Coming

I'm preparing to move the site to a new platform. Within a day or so the site will be hosted on a new content management system, which will allow us much more flexibility with all the new tools and content coming this season. I'm not sure how smooth the transition will be, so please stay tuned via Twitter in case things get broken over the next couple days.

With the url  (web address) change earlier this year and now this change, I've completely destroyed the site's search rankings (which were really good), links, and 7 years of goodwill. I apologize.

To fix things, I'll need your help. Please update your links to the site's url and, more importantly, spread the word. Hopefully you've enjoyed reading the posts or using the other features at AFA over the past several years. I haven't asked much in return, so please give the site a shout out on Twitter, your own site, or whatever platform you have.

Just to be perfectly clear, here are how things are changing:

1. The new site will offer all the same content you've come to expect, including analysis, tools, live WP graphs, advanced stats, the podcast, advanced boxscores, and visualizations. In addition, it will have a separate section for team clients and media outlets who use AFA services.

2. The web address will continue to be

3. The twitter handle will remain @Adv_NFL_Stats.

4. The site's feed will change to  (or ...&type=atom, depending on your preference.)

5. The podcast feed will continue to be

6. For now, older content will continue to be hosted at

For the month of October I'll be celebrating the re-launch of the site with a feature of the day, highlighting many of the most popular things the site has to offer.

Biggest Plays of the Week

In case you miss the links I send out on Twitter, Deadspin's sub-site Regressing is running a series on the biggest plays of the week. I created a tool for them them lists the biggest plays in terms of Win Probability Added (WPA).

Reading the comments, people seem to take delight in the negative plays for whatever reason. Cutler's interceptions appear to invite a lot of anti-fans. There's also loyal fans who like to pile on the misfortunes of their own team out of frustration. I can see that this week with E.J. Manuel's bad day yesterday.

But keep in mind a "negative" play is all in the perspective. A bad play to an offense is a great play to a defense. Statistically, there is no good and bad. Manuel's interception to Watt was both a poor by play by a quarterback and an alert and athletic play by a defensive lineman.

If and when Regressing gets tired of posting these, I'll make the tool public so you can look up the most agonizing moments in your hometown team's season anytime you want.

Sunday's Numbers Have Been Crunched

Sunday's numbers are now available, including advanced stat box scores, top players of the week, team stats, and season leader boards.

Team Advanced Stats Viz
Position Leaders Viz
Advanced stat box scores
Top QBs of the week
Top RBs of the week
Top WRs of the week
Top TEs of the week
Top Defenders of the week
Advanced team stats
Offensive player season leaders
Defender season leaders
QB Viz
RB Viz

Chip's Challenging Decisions

The Eagles lost to the 49ers on Sunday 26-21 in what essentially came down to two plays by the Eagles on 3rd and 4th-and-Goal from just outside the 1-yard line. There is no denying it was a close game - even though the Eagles offense was unable to move the ball all day. The Eagles made a few interesting decisions - or lack of decisions - in the second half including not challenging a 3rd-down conversion reception and accepting a penalty on 3rd-and-3 after an incompletion. Let's examine each and see how they could have affected the Eagles' win probability, keeping in mind that in close games, every percentage point counts.

Throw The Red Flag

With 2:09 left in the 3rd quarter, winning 23-21, San Francisco faced a 3rd-and-9 from their own 27. Colin Kaepernick dropped back and hooked up with Anquan Boldin for a 12-yard completion. It appeared Boldin bobbled the ball and potentially trapped it on the completion. In today's game where most of the biggest plays are automatically reviewed (scoring plays and turnovers), a long 3rd-down conversion in a close game is one of the higher leverage challenge situations.

One Thing I Learned from the WOPR

How can TB upset PIT? How does MIN overwhelm ATL with a rookie QB? How did the NYG offense suddenly break out with 45 points? How does DAL embarrass NO on both sides of the ball?

The WOPR is my game simulation engine. I've had a ton of fun experimenting with different things, finding out when teams should make various tactical decisions that might be uncommon or hard to isolate empirically (directly from the data). But one of the more profound things I learned from the WOPR relates to game outcomes between completely even teams.

Weekly Game Probabilities - Week 4

Weekly game probabilities for week 4 are now up at Sports on Earth. Probabilities are a blend of the pre-season team strength estimates with a strong dose of stats from weeks 1, 2 and 3.

Please remember that the projected scores are not to be taken terribly seriously. Do not bet the mortgage on them as they are not intended to graded against the spread. They are simply a "maximum-plausibility" estimate given respective team scoring tendencies.

Team Efficiency Rankings: Week 3

The return of the team efficiency rankings comes with some important changes for 2014.  As most of you know, Brian revamped the win probability model for this year to provide more precise estimates in a greater variety of contexts.

This obviously holds big implications for the rankings, which are based on the generic win probability (GWP) of a particular team against an average team.  But more importantly, both are predictive models which emphasize factors that best suggest how likely a team is to fare in the future.  When one improves, the other should theoretically improve alongside it.

We'll keep an eye on that hypothesis as the season moves along.  Perhaps I'll write something at the end of the season comparing the accuracy of this year's model to 2013's.  For now, let's take a look at some of the most notable trends from the first rankings of 2014 (click here for a full explanation of the rankings methodology).

Leaving Free WP All Over the Field

If you were a coach, would you voluntarily give up a down at some point in the game, just to be sporting? Ehh, let's just make it 3rd and 5 instead of 2nd and 5. Of course not. For a random play in the 2nd quarter, that would cost you about 0.02 WP (2% chance of winning) for no reason.

So why do NFL coaches voluntarily leave WP out on the field?

Take yesterday's DEN-SEA game as an example. SEA was ahead 17-12 in the 4th quarter, and had the ball deep in their own territory with about 9 minutes to play. With the game clock running, they snapped the ball with: 8, 5, 5, 8, and 10 seconds left on the play clock. That's a total of 36 seconds. Plus, there was a play in which the receiver could have just as easily remained in bounds. Because there was more than 5 minutes left in the game and the clock restarts after the ball is set, that may have only cost 10-15 seconds of play clock rather than up to 40 seconds. To be fair let's say there was a total of 46 seconds SEA could have burned off the clock during their second to last drive with almost no effort or risk.