What Is Football Analytics?

Analytics in football is one of the hot topics in recent years. What began as a hobby for guys like me has turned into a serious and growing field. It's been gaining attention in the media, and now teams themselves have begun to pay attention, many of which have hired analysts to help provide insight to decision makers.

"Analytics" has unfortunately become a trendy buzzword in sports. I've found that many people who are only vaguely familiar with analytics, including some team executives, media members, and fans, have the wrong idea about what analytics is. Some think it's a panacea that can optimize the solution to any problem. Some think it's just statistical trivia or scientific minutia, like ESPN's Sports Science series (Dwight Howard's arm-span is as big as a 2-car garage!). Others think it's just Moneyball, a one-time talent arbitrage applicable to only one sport. So I thought I'd put my own thoughts down on what analytics is, at least as it applies to football.

I'm not the gatekeeper on what qualifies as analytics, and I'm not going to say what counts and what doesn't. But I think analytics comprises all or parts of four general processes:

Thoughts on the Extra Point

Roger Goodell is considering elimination of the extra point. I've been whining for 5 years now, advocating some kind of change to the XP. I just hope the league doesn't mess it up, like they did with overtime.

I realize quoting myself is not in good taste, but then again I've never been accused of good taste. Here are some of my thoughts.

Kicking field goals is such a peculiar and specialized thing. It has almost nothing to do with the rest of the sport but can be so decisive. It would be like getting extra runs in baseball by lacing up some skates and slapping a shoot-out shot after every home run.

Here's an excerpt from a diatribe in my old Washington Post column.

The extra point is something left over from gridiron football’s evolution from rugby. Originally, the ‘touchdown’ in rugby was less important than the ensuing free kick, and the points given for the touchdown and the ‘point after try’ varied during football’s early history. Today’s extra point is a vestige of football’s rugby roots. It’s football’s appendix–inconsequential, its original purpose uncertain...and safe to remove.

It's easy to see that XPs are pretty pointless, but it's harder to come up with some good ways to fix them or replace them. Here are some of my favorite ideas (and plenty more in the comments):

Worst Article about Football Analytics of 2013

I came across this article from a website called Trending Buffalo just yesterday. It's from September, but unfortunately it's one of the top 10 results if you google football analytics. Although the author is misinformed or uninformed or both, I sense that his feelings are shared by a large number of fans and traditional analysts in the media. So I thought I'd respond point by point.

From 'Trending Buffalo' Sep 13, 2013
http://www.trendingbuffalo.com/sports/buffalo-bills/5-reasons-football-analytics-arent-as-great-as-you-think-they-are/

1. YOU DON’T KNOW WHAT YOU DON’T KNOW
Precise breakdowns of every player on every play of every game can be found on countless websites [countless?] but “Player X failed to execute his route” and “Player Y is responsible for the B gap” ring pretty hollow when you don’t know what the players were supposed to do. [The author doesn't understand what analytics is. It's not amateur scouting.] Remember when Doug Flutie discredited analysts because “You watch the game. We watch the film”? He should’ve added “and we know the play calls.” Without that crucial information, your analysis is a really, really in-depth GUESS. [Football analytics is a lot of different things, combining tools from several disciplines, but it's not about guessing assignments on plays. I suppose the author doesn't care for Pro Football Focus, which isn't strictly 'analytics' on its own. But I'd submit that even though PFF doesn't know 100% of the assignments, most can be easily inferred. It's far from perfect, but it's a big step forward for public player evaluation and a giant leap beyond traditional punditry.]

The New Overtime Format Is a Complicated Mess--Here's How to Fix It

Dear Competition Committee:

The ostensible purpose of NFL overtime is, first and foremost, to declare a winner and avoid a tie, and second, to do so quickly. If ties were acceptable, I assume the league would not bother to even have overtime.

In recent years, as offenses gradually gained an ever stronger upper hand over defenses, it became clear that the former sudden death format gave too much advantage to the winner of a trivial coin flip. We saw time and time again as a team won the coin toss, got a decent return, earned a couple first downs, and kicked a long field goal without even a whimper from the unlucky loser of the coin flipping contest. Something needed to be done.

And, unfortunately, "something" was done. The current format is a mess because its effects are contrary to both stated purposes of overtime. It increases the chances of a tie while a prolonging the overtime period.

The new rules are complex and non-traditional. In the event the team with first possession scores a field goal, the opponent now has a drive opportunity with all four downs and no pressure of time to respond. And the rules still favor the team that wins the coin toss.

Here is what I think is a much better and far more elegant solution, which is fair, traditional, avoids ties, and leads to much quicker resolutions:

Is Sabermetrics Helping to Ruin Baseball?

Caution: A lot of opinion to follow. And please understand I love baseball and I obviously am a believer in analytics.

Imagine a world in which baseball teams had no idea how good or bad a player could be expected to perform from year to year. All players would be total blank-slate mysteries. In this world, it wouldn't matter at all how high or low a team’s payroll is. A team that spends $1M on payroll would be just as likely to win a championship as a team that spent $200M. The correlation between payroll and wins would be zero.

Now imagine the opposite scenario in which teams had perfect crystal-ball foresight about exactly how well a player could be expected to perform. Now the team with the highest payroll would always have the most wins because there would be a 1:1 direct linkage between performance and pay. This would make the correlation between payroll and wins a perfect 1. We wouldn't even need to play out the season. Just mail the trophy to the team with the highest payroll and save everyone the trouble.

In reality we’re about halfway between the first case and the second case. We neither have no idea about expected performance, nor do we have perfect predictive knowledge.  MLB's correlation between team payroll and wins has been trending at about r = 0.4. It varies from season to season, but its recent central tendency appears to be right round 0.4.

The problem that analytics causes is this: The better the sabermetrics (or the more uniformly adopted it becomes), the better the crystal ball becomes and the closer we move toward a correlation of 1...which, by the way, is a bad thing. Of course, we'd never see a correlation of 1 because of injuries and simple randomness, but it could get much higher as it did in earlier eras. The correlation has been higher and lower in years past, varying for reasons that have nothing to do with analytics. But the point is that sabermetrics, to the degree it is effective, makes the correlation higher than it otherwise would be, and this gives an ever greater advantage to big-payroll teams.

On the Effect of Coaching

There are exceptions, like that guy on the left, but my hunch is that NFL coaches are mostly interchangeable.

I think at the NFL level, all coaches employ the same best practices. There is no secret sauce that one coach has over another in terms of instruction, motivation, strategy, etc. This is because of the highly mobile, fluid market for coaches and the large size of their staffs. There are very strong constraints on deviation from league norms in any dimension.

Also, from statistical analysis, we can measure the variance in team performance attributable to randomness (sample error due to a short 16-game season) and player impacts (the addition or subtraction of a player's impact on team production, player interaction effects). There is very little variance left that can be attributed to other causes, including coaching. In other words NFL outcomes are overwhelmingly driven by player talent and luck, and there's not much room left for coaching to make a big impact.

We can observe this intuitively, as the very same coaches can have wildly different records from year to year. How much effect can they really have?

Attention All Offensive Coordinators

Fourth down and short in the middle of the field does not mean you need to run a goal line play with the jumbo package. The average play in the NFL gets 5 yards. What's the completion percentage for short passes in this league, like 75%?

Line up and just run a standard play. Use play action. Throw an intermediate or deep pattern once or twice a season to keep defenses honest. How about a bubble screen if the corners don't press. And if they do, let them get burned.

Do not telegraph your intent to plunge for the line of gain. That only makes the defense's job easy. Spread out and force the defense to defend the entire field and your success rates will improve. Punish the defense for crowding the line of scrimmage. Think of fourth and short as an opportunity to know exactly what the defense is going to do and take advantage of it.

On the goal line, it's different. There is very little of the field to defend, and yards gained beyond the goal line are irrelevant. Jumbo packages and plunges make a lot more sense.

Analytics and the Ludic Fallacy

Analytics have become a major part of political campaigns. Candidates now employ a large number of analysts who find every point of leverage possible. They target potential voters in ever narrowing slices, matching messages containing certain styles and emphasis with particular demographic audiences.

One of the most visible applications of analytics in this year’s election is the FiveThirtyEight blog, created by Nate Silver. For those who may not be familiar with Nate, he is a noted baseball sabermetrician best known for creating the PECOTA prediction model. His election forecast has favored Obama more heavily than most others throughout the election season, and he has been the target of criticism recently.

In defending his approach, Nate and others have explained his probabilistic reasoning with examples from football. The 90% or so chance Nate gives Obama to win the Electoral College is, for some reason, put in football terms…Romney is down by 3 with 2 minutes to play…or Romney is down 7 with 5 minutes to play…or something along those lines. (I think that's ironic given that even football experts don't seem have a good grasp of situational probabilities.)

I disagree with those analogies, but not because I have any better reason to think that either candidate will win. I think the situation is more like this: Romney is down by a very small number of points with 1 minute to play, and we don’t know who has the ball or where the line of scrimmage is. Or maybe it’s more like this: Romney is down by a point or two and has just snapped a long field goal attempt, and no one has a very good idea which way the wind is blowing. If it was blowing just like it was last game, the kick will almost certainly come up short. But if the wind is blowing more like it did two games ago, he’ll probably make the kick and win.

The Extra Point Must Go

This week's article at the Post asks What's the point of the extra point?

 The extra point is something left over from gridiron football’s evolution from rugby. Originally, the ‘touchdown’ in rugby was less important than the ensuing free kick, and the points given for the touchdown and the ‘point after try’ varied during football’s early history. Today’s extra point is a vestige of football’s rugby roots. It’s football’s appendix–inconsequential, its original purpose uncertain...and safe to remove.

Will the New Kickoff Rules Really Reduce Injuries?

The NFL play-by-play reports when players are injured on each play, or at least when the injury stops play so trainers can attend to the injured player. These are far from 100% all injuries suffered in the course of play, but they are the ones that tend to be significant or severe--ACLs, broken bones, separated shoulders, concussions--the kind of things that really worry players, teams, and the league.

With that information in hand, we can see the injury rates for each type of play, including kickoffs.

Unplug

“News is to the mind what sugar is to the body.”—Rolf Dobelli

You may have noticed there has been a labor action here at Advanced NFL Stats. I’m on a work slow-down, taking a vacation from all the lockout noise. Apparently there’s an NFL lockout going on, and there may or may not be full, normal NFL season this fall. That’s all we know, and that’s all we need to know as fans. That’s the signal, and everything else is noise.

Weeks ago I unsubscribed from rumor mills like Pro Football Talk on my RSS reader. I avoid articles in the sports pages about the lockout and change the station when the local sports talk veers into lockout soap opera. Too much of it is gossip, rumor and speculation, and it’s a giant waste of time.