Philly's Inferno

A sports fan’s opinion through the lens of Philadelphia’s seventh circle of hell.

Month: July, 2013

Explaining the Eagles’ High Performance Mindset

“What the hell is that?” This was my reaction when I saw the photos of the Eagles video schedule from Jimmy Kempski and Sheil Kapadia.  On the screen in green, after “Lunch” and before “Special Teams Meeting”, was listed “High Performance Mindset Meeting.”  It sounds bad ass, and it turns out it was.  Chip Kelly (and I’m thinking Sports Science Coordinator Shaun Huls had a hand in this too) brought in a guest speaker, Navy SEAL officer Coleman Ruiz, to talk about his mindset when on the battlefield and how it could apply to the football field.  But what exactly could Ruiz have talked about.  Well, I’d like to venture a guess…

First, let’s get back to Shaun Huls.  If you have not read Jenny Vrentas’ profile on Huls, please do. It’s required reading.  According to Vrentas, Huls spent five years training Navy SEALs in a military base in Virginia Beach and was the first strength coach hired to work in a human performance program at Special Warfare Group 2.  Not only did Huls train and coach, but he participated in typical SEAL exercises in order to fully understand the strains on the human body, both mental and physical.  I think it may have been here where Huls was introduced to something called “Comprehensive Soldier Fitness”.

Much as it is with any kind of technology, the military is often where new science is first applied.  Ever since Martin Seligman’s inception of positive psychology, there has been a revolution in studying how to enhance the function of our brain and our behaviors in order to maximize well-being and performance.  Books have been written (The Oxford Handbook of Happiness) and business and self-help courses have been created (Michael Bernard’s “High Performance Mindset”) in order to capitalize on this new field of research.  But the military is where the benefits, or at least the early returns, can be seen.  (Note: Seligman’s Positive Psychology Center has a webpage devoted to this, what he labels as Army Resilience Training.)

The military’s Comprehensive Soldier Fitness (CSF) program has a Performance Enhancement track, which is “based on four decades of scientific research and recognized best practices in the field of sport and performance psychology. The tenets underlying excellence in human performance are applicable to all professional occupations. The mental and emotional skills required to excel on the athletic field are similar to the skills underlying excellence on the battlefield, in the classroom, in the workplace, and at home. Given this understanding of human performance, [CSF] tailors the delivery of the program to meet the needs of a wide spectrum of Army organizations and populations.”

Here is what CSF looks like:


Mental Skills Foundation
Identify the mental skills that underlie performance and understand the psychology of performance excellence.

Building Confidence
Develop effective thinking skills to create energy, optimism, and enthusiasm and help manage internal obstacles that hinder performance excellence

Attention Control
Employ methods to take control of your attention, improve your ability to attend fully and concentrate amidst distractions.

Energy Management
Use self-regulation skills to effectively modulate and restore energy in order to thrive under pressure.

Goal Setting
Develop a concrete, step-by-step plan for achieving a personally meaningful goal and maintaining the motivation necessary to be successful.

Integrating Imagery
Mentally rehearse successful performances to program the mind and body to perform automatically and without hesitation.

Looking at this program through the lens of the NFL, we can get a clearer picture of what Chip Kelly and Shaun Huls want this football team to look like: a Philadelphia Eagles team that can be mentally tougher and more fundamentally sound than any Eagles team in a long time.  To this end, I don’t expect Tuesday’s “High Performance Mindset Meeting” to be limited to just one session.  I expect it to be an attitude and practice that pervades training camp, the season, and hopefully, the organization as a whole.


An Argument against Fumble Recoveries and Luck

Throughout time immemorial humanity has attributed unexplainable phenomena to magic, God, superstition, or luck. Applications to the insanities that occur in football are no different.  Footballs veer ever so slightly left of the upright. There are obstructed views. Blown calls. All of these things and more we commonly attribute to the quirks of fate, or, luck. That is, until we fully understand what’s actually going on.

I think we do this when trying to understand fumble recoveries.  Check out this series of articles by Brent over at

What’s the Deal with Fumbles? (Should we worry about Bryce Brown?)

Fumble Luck… Again

Forced Fumbles Skill and Give/Take Recovery Rates

He has expertly provided a strong case (which supports the work of several others) that fumble recoveries are a function of chance.  Despite his evidence, and despite my own research, I still find it hard to believe.  I’ve performed dozens of regressions (at least 60, both linear and logistic) comparing this statistic to that, from this year to that, hoping to find some relationship that explains the seemingly random nature of fumble recoveries.  Do they correlate to yards?  No.  Do they correlate to wins?  No.  The overall strength of a defense?  Sacks?  All no. I am usually the first to say, “Well if the numbers say it, then it must be true.”  And these numbers indeed suggest fumble recoveries are a function of luck.  So what’s my beef?

Maybe it’s philosophical.  Primarily, I’m a believer that there is no such thing as luck or chance.  I believe we make our own luck, be it good or bad.  And fumbles, be they accidental or forced, and recoveries, by the offense or defense, must be a product of concentration and skill rather than the whims of chance.  But, for the life of me, I just can’t accept the latter.

I think fumble recoveries are the product of the type of fumble.  Fumbled snaps (lack of concentration on the part of the center or quarterback) are more likely to be recovered by the quarterback, right? At that point there are fewer defenders around the ball.  Fumbles by running backs (lack of concentration and technique on the part of the quarterback or running back) are likely to be recovered by the offense if it occurred on the offense’s side of the line of scrimmage, and likely to be recovered by the defense if the fumble (forced or not) occurred on the defense’s side of the line of scrimmage.  I would think that’s what the odds would say. Right?

As it turns out, I think they do.  Luckily for me, Chase Stuart over at categorized the types of fumbles and the types of recoveries for the 2000-2011 seasons.  Here is his chart:

Fumble Recovery Rates - FootballPerspective

His chart tells us how each type of fumble was either recovered by the defense (DEF), offense (OFF), the fumbler (RBF), or whether the ball went out of bounds (OOB).  At first glance, note the prevalence of the red (DEF) color.  For the first four bars, all quarterback related, fumbles are most likely recovered by the offense.  This makes sense, since the fumble most likely occurred on the offense’s side of the line of scrimmage and should most likely be recovered by an offensive player.  The exception is sacks, which also seems to make sense (to me anyway).

The last two bars illustrate events that most likely occur on the defense’s side of the line of scrimmage. During these fumbles, the number of defensive players surrounding the ball in the defensive zone (swarming?) probably outnumbers the number of offensive players.  Again, this seems to make sense.  (Note: this is my interpretation of the data, not necessarily Stuart’s.)

So what can this tell us about luck?  My hard stance: when a football veers just left of the upright, it’s because of a poor snap, hold, or kick; when there is an obstructed view, someone is out of position; a blown call is a result of poor judgment.  Lastly, a fumble recovery is a product of the type of fumble, the location of which is a function of some player’s concentration and skill (or in some cases, lack thereof). Is all of this definitive proof that fumble recoveries are not a product of chance?  Probably not, but it’s still a valid argument.  Measured in the aggregate, fumbles and fumble recoveries appear to be random products of luck.  But when broken down and dissected, when we calibrate the microscope a bit deeper, we can see things a little differently, and perhaps clearly.

Dictating the Pace – Illustrating How Playing Fast Offers an Advantage in the NFL

I previously examined how Chip Kelly’s desire to play fast can be advantageous for the Philadelphia Eagles. Here is an interactive Viz to further illustrate.  Click on the image to interact.

Dictating the Pace Viz

Dictating the Pace – Examining How Playing Fast Offers the Philadelphia Eagles an Advantage

Update: Click here for the interactive graphic (Viz) illustrating the advantages of playing fast in the NFL.


There once was a man from Nantucket
When young he held a football and chucked it.
When older, Football had him
So one day he chose, on a whim
To tell Football Convention to suck it.


By now, we know the story.  When Chip Kelly presided over the University of New Hampshire football program (he’s not from Nantucket, but close enough), he struck a friendship with Bill O’Brien, who coached at Brown.  The two men have shared meals, drinks, laughs, and maybe a secret handshake or two, but more importantly, they talked a lot about football.  It was this connection that brought Kelly, the Oregon coach, to Foxboro to see O’Brien, the New England Offensive Coordinator, who then introduced Kelly to Patriots head coach Bill Belichick.

Fast forward to the 2012 NFL season, Week 5, in a game littered with Chip Kelly’s fingerprints.  A blistering-quick no huddle offense paced the New England Patriots to a 31-21 victory over the visiting Denver Broncos.  The Patriots ran 89 offensive plays, second most in franchise history, and set a franchise mark in first downs with 35. According to Boston Globe writer Greg Bedard, this one game serves as a fine example of the impact Kelly has had on Belichick and the Patriots’ offense.  It also serves as a good case study for what the Philadelphia Eagles expect to become.  In that regard, much has been written about how Chip Kelly, either through his offense or coaching technique or whatever, will change the NFL and revolutionize the game of football.  Revolutionize, he won’t.  However, more simply and rather elegantly, Kelly will be executing a strategy.  But is it a strategy that will work?

There are some who claim that a byproduct of running a faster paced offense is a defensive unit that will spend more time on the football field.  By this logic, a team that wishes to play fast offensively will also need to employ a defensive unit that is deeper and/or better conditioned than the average NFL defense.  However, while still a nice luxury, this may not be the case.  During the New England Patriots win over the Denver Broncos last season, the Patriots’ 89 offensive plays encompassed 36 minutes of time, leaving the Patriots defense on the field for 24 minutes (against Peyton Manning). Granted, all games are not equal, and it would be unfair to transpose this one game onto what the Eagles hope to accomplish over time.  Yet, if we compare the number of offensive plays to defensive plays in games during the 2009-2011 seasons, we see a mild and statistically significant relationship.  As the number of offensive plays increases, the number of defensive plays decreases.  This could indicate that poorer defenses facilitate more offensive plays.  Or it could not (a poorer defense could allow an offense to score using less plays, who knows).  At any rate, it appears, at least historically, that the Eagles’ defense may benefit from a faster paced offense that runs more plays than average.  (Obviously, this point becomes moot if their defense routinely executes “three-and-outs”.)


When using total offensive plays to measure the speed of an offense (that is, how fast the offense operates and executes), we can glean how successful the “play fast” strategy has been.  From 2009 to 2011, teams that run more offensive plays than their opponents win 58% of the time.  Over a sixteen game season, this translates to a 9-7 record; not exactly indicative of a full-proof strategy (again, it could also illustrate that all defenses are not created equal).  But this is a case where a descriptive statistic does not tell the whole the story.

In order to really maximize the effect a high number of offensive plays has on the outcome of a game, let’s assume (based on above) that Chip Kelly just isn’t just interested in executing a shitload of offensive plays; he’s equally interested in executing a shitload more than his opponent.  Unfortunately, according to linear regression, this strategy does not necessarily equate to scoring more points than an opponent.  From 2009 to 2011, there is only a slight positive relationship (if any at all) between team offensive play differential and point differential per game.


Logistic regression, on the other hand, tells us something else.  Using this model, we can determine historically to what degree running more offensive plays than an opponent has helped win games, and project the impact going forward.  And, as it turns out, different degrees of offensive play differential has indeed had an impact on game outcomes.  From 2009 to 2011, teams had a 50% chance of winning when their offensive plays are equal (actually, this behavior favors the home team… more proof of Home field Advantage?).  For each additional offensive play above 50%, a team gives itself a 2.65% better chance of winning.  For every ten plays above 50%, a team gives itself a 35.1% better chance of winning; every twenty plays, a 49% chance of winning.


We can retroactively apply these models to the New England/Denver game, where the Patriots ran 23 more plays than the Broncos (89-66).  According to the 2009 to 2011 linear and logistic models, this translated to the Pats having a 65% chance of winning the game (70% at home) by 8.2 points (they won by ten, 31-21).

Moving into the future and shifting back to the Philadelphia Eagles, let’s assume that Chip Kelly would like to average 20 more offensive plays than his opponents.  This would translate to a 63% chance of winning (68% at home, 57% away), by an average of six points (seven at home, five away).  Applying this strategy (if executed) over a 16 game season, the result could be a 10-6 record.  However, I think it might be safer to conclude that a team which averages ten more offensive plays than its opponents can attain one more win than if offensive plays were equal; a team that averages twenty more offensive plays can attain two more wins, and so on.  Despite their 89 play effort against Denver, the 2012 New England Patriots averaged nine more offensive plays than their opponents, so one of their twelve wins can be attributed to this differential.

Based on these results, it does not appear to me that a revolution is on the horizon. However, Chip Kelly will be implementing a strategy, and a sound one at that.  History tells us if Kelly’s offense averages eighty plays per game (twenty more than his opponents) his defense will be on the field for six plays less per game than the league’s season average and his team will have a 49% better chance of winning each game.  In this regard, playing fast does seem to offer an advantage. Yes, intentionally increasing offensive plays has not been the typical NFL convention.  But in the end, Chipper doesn’t really care about that, does he.

Philadelphia Eagles Must Re-Establish Home Field Advantage

Originally published June 4, 2013 on

Really, this headline could apply to any team in Philadelphia.  Hell, any team in the country.  But if Doug Collins, the recently re-allocated former 76ers head coach, did one thing right, it was to instill his desire to establish a presence on home court.  “We don’t lose two in a row at home,” he said.  While this mantra focused a bit on the negative (why not simply say, “We will win at home”), the message was received.  The 76ers were not a team that played well anywhere, but improvement needed to start at the Wells Fargo Center, and it did.  Chip Kelly inherits a Philadelphia Eagles team in a similar situation.  His Eagles have not played well, and in order to turn things around, Kelly needs to re-establish a strong home presence.

I recently examined the factors that contribute to home field advantage (HFA) in the NFL and found that HFA is impacted by team success, offensive efficiency (which includes penalties), and turnovers.  These factors can affect the home crowd, and the home crowd, in turn, can have an effect on these factors. (Note: this is a recommended read if you want more detail about the results discussed here.)  Read more…

What Contributes to Home Field Advantage in the NFL?

Philly's Inferno

Note: If you would like to jump to the interactive NFL Home Field Advantage infographic, click here.

I will never forget “Fourth and 26”. It was early in the morning when we arrived. The parking lots at Lincoln Financial Field were already filling up and it was brutally cold. My friends and I dressed for it – I wore twelve layers – and we brought plenty of food to grill and plenty of beer to drink. The beer we had to drink quickly, because at eight degrees a layer of ice formed on the surface. More than once I tilted a half- full can to take a sip and nothing followed. It was a cruel joke. Regardless, the twelve layers and amount of beer I drank made taking a leak a torturous endeavor. But in reality, there was no better place I would rather have been than that frozen…

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The Science Behind Chip Kelly’s Use of Music

Originally published May 16, 2013 on

I was one of many Eagles’ fans following the Twitter updates during the team’s OTA Monday.  And I was probably one of the many getting annoyed by the flood of tweets regarding Chip Kelly’s music playlist (more football please!).  But as seems to be the case more often than not with Coach Kelly, there is a reason for everything.   Afterwards, Kelly was asked about including various rock and pop anthems on the practice field.  He answered, “There’s some science behind it…” He didn’t have the time to elaborate, but there are indeed football and non-football reasons for it, and I think they go hand-in-hand.

First, let me preface this by saying that my undergraduate degree is in Psychology, so this kind of stuff – understanding how and why we do what we do, think how we think – fascinates me.  I was able to dig around and found an article by Associate Professor of Education Mary Ann Davies (Northern Arizona University) titled “Learning… The Beat Goes On”, in which Davies summarizes research on how, and how well, music aids our learning and retention of knowledge.  The article was from the journal Childhood Education (Spring, 2000) but was written to encompass education in general.  Reading it within the context of football is really interesting.  Read more…

Hey Jeffrey Lurie, Bring in Brian Dawkins

Originally published May 10, 2013 on

When Chip Kelly provided the names of his coaching staff, I was one of many Eagles’ fans hoping Brian Dawkins would be one of them. At one point it even seemed likely, especially after Kelly paid Dawkins a visit at an event Dawkins hosted at Chickie & Pete’s in late January. Alas, it was not so, and I now think Dawkins, while perhaps open to coaching in the NFL one day, is more devoted to his family and would not necessarily want to spend the amount of time away from his wife and children that coaching requires. However, I have a proposal…

Jeffrey Lurie has demonstrated an ability to think outside the box. He also seems to have surrounded himself with like-minded individuals, especially recently. In the spirit of Chip Kelly’s hiring of Shaun Huls as Sports Science Coordinator, I propose Lurie create a new front office position for Dawkins: Director of Leadership and Impact. Here’s why: Read more…

Improvement Ahead – Philadelphia Eagles 2013 Win Probabilities

Originally published May 3, 2013 on

The NFL Draft is over, and while we wait for the OTA’s and mini camps, it’s time to focus on the Philadelphia Eagles’ 2013 schedule.  For a Chip Kelly squad that will want to play fast, the NFL *cough* graciously accommodated.  The Eagles open the season with three games in 11 days, and two of those games are during prime time, so we may know pretty quickly how Kelly’s team responds to high speed and short rest.  Hopefully smoothies help.  But in actuality, how might the team perform next season?

Before the draft, I took a cue from Bill James and used Pythagorean expectation to project the Eagles will win five games in 2013.  However, that did not take into account their opponents, who were unknown at the time.  Now that we know who the opponents are, I applied the same Pythagorean expectation formula to them, and used those results as the basis for simulating the Philadelphia Eagles 2013 season.

The model takes the Pythagorean wins for the Eagles and their opponent each week, randomizes those values within the standard error value (2.6 wins), and applies a random “external factor” value to each team.  I included the external factor value to randomly, and cumulatively, account for things like luck, home vs. away games, day vs. night games, win/loss streaks, weather, game planning, the impact of a certain new head coach, etc.  I ran the simulation 1,000 times, so the external factor value changes for each team in each simulated game.  For each game, the products of the modified Pythagorean wins (based on standard error) and external factor values for each team are compared, and the team with the higher product is awarded a win.  Read more…

Hello Matt Barkley, Goodbye Michael Vick

Originally published April 27, 2013 on

If I am Michael Vick, I am not happy.  If I am Vick, I know I am a veteran, injury-prone quarterback with turnover issues and I know I have to compete for a roster spot.  Not a starting spot, but a roster spot.  I know I have to outperform a younger mini-me who has a head start understanding head coach Chip Kelly’s offense (Dennis Dixon).  I know I have to outperform a young competitor who outplayed me behind the same terrible offensive line (Nick Foles).  And I now know I have to outperform Matt Barkley, a hungry fourth round draft pick from USC with something to prove, who is apparently… ahem… leadership-prone.

Barkley is a surprising pick in more ways than one.  First, he was initially projected to be a first round talent.  Second, he was generally and universally believed to not fit the Eagles offense, whatever that offense may look like.  Third, the Eagles traded up a few spots to get him. Exactly what Howie Roseman and Kelly got was a player high on intangibles and low on risk.  Read more…