Proof of Exponent's Incompetence

[tom.kordis]

[Part 1]
I just sent this letter to Roger Goddell. I'm pessimistic about any effect it might have, but I thought I'd post it here.

In short, Exponent's model for their "Patriots' Wet Football" was fatally flawed by virtue of being massively "under-wet".
Their model gave them their "Warming Time Constant" and "Equilibrium Pressure" for their "undeflated Patriots football".

Since the Patriots' footballs did not match their model, they concluded that "someone delated the balls".
Exponent's assumptions are wrong, their model is wrong, and their conclusions are wrong.

Here's absolute proof of that assertion.
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[Letter to Roger Goodell & Troy Vincent]

Sirs,

By way of introduction, I have been a mechanical engineer for the past 41 years. I have a vast background in designing, executing and writing Engineering Test Reports for a wide range of engineering firms & agencies, including NASA, Boeing, the FDA & many others.

In short, I know what I am talking about. This is my profession.
You really should listen very carefully to what I am about to tell you:

You are on a course to give yourselves a reputation as the most profoundly incompetent buffoons in Sports History.

Nobody deflated any footballs during the Patriots/Colts game in January, 2015.
The simple fact that you were not capable of determining this self evident fact in about 4 minutes with a pen, a scrap of paper & a calculator simply proves your ignorance of the technical issues.

Please don’t be insulted by my statement above. The physics of gasses is not your field.
Nonetheless, as uncomfortable as it may make you feel, my statement is completely accurate.

There are approximately 2 million competent mechanical & chemical engineers in the US alone, and every single one of us who have looked into this issue (except one willfully incompetent, hired-gun engineering firm, paid to come to a biased conclusion) has come away with exactly the same conclusions:

1) The NFL is utterly incompetent regarding the technical issues of pressure vs. temperature vs. moisture content in footballs.
2) The NFL is utterly incompetent regarding the technical issue of “taking any sort of measurement”. (See ISO standards, in last paragraph below.)
3) The NFL regulations regarding the pressure & weight of footballs is incompetent & unenforceable.
4) Nobody let any air out of any footballs prior to, or during, the Patriots/Colts game on Jan 18, 2015.

The US’s engineering establishment is, frankly, startled & bemused at the level of incompetence of the NFL, regarding an issue as trivial as this one. The simple fact that you seem to find this simple issue to be complicated or difficult to understand underscores the woeful state of affairs.

And yet, have you made the slightest effort to reach out to engineers for some assistance?
No, you have not.

You’ve reached out to a wretchedly biased law firm, who hired an engineering-firm-for-hire, whose sole purpose is to provide lawyers with “legal technobabble that supports whatever answer they want”.

And you have accepted their junk engineering report.
That was a very bad move that will come back to haunt you and your reputations, in about 6 months from now.

[End Part 1]

 

[tom.kordis]

[Part 2]

You seem to think that you are locked in a fight with Tom Brady & the New England Patriots over the issue of the deflation of footballs.
You seem to think that this issue can be decided by lawyers (Mr. Wells, Karp & Reisner), a biased and, by all evidence, a willfully incompetent engineering report (Exponent’s report) and/or by business executives (such as yourself).

You could not possibly be more wrong about all of the above.

You are locked in a fight with Mother Nature.
And she is going to stomp you.

She is unforgiving.
You cannot bargain with her.
You cannot influence her.
You cannot negate her with an executive decision.

Come next November, December & January, once the weather turns cold, and every single teams’ footballs “deflate” exactly the same way that the Patriots balls did, what are you going to say to Tom Brady, Robert Kraft, the New England Patriots, the other NFL teams, the NFL fans?

What are you going to say to a unforgiving & predatory News Media, which will then smells your blood in the water, instead of Tom Brady’s?

Trust me, sirs.
This is not a “what happens IF everyone’s footballs deflate?” situation.
This is a “what happens WHEN everyone’s footballs deflate?” situation.
You really should think about what you will say, come that inevitable event.

Trust me on one other issue: You cannot further impugn the reputation of Mr. Brady. As I’ve explained, come this winter, Mother Nature will deliver her verdict: Mr. Brady has been innocent, and telling the truth, all along & those that convicted him based on ignorance & junk engineering are technically incompetent and (to a high probability) willfully biased.
__

I am happy to inform you that the following graphs prove that the report that you received from Exponent Laboratories via the Wells Report is fatally flawed.

Others have addressed the weaknesses of Exponent’s junk statistics & lawyer-determined assumptions.

I will take a different tack: I’ll point out for your their engineering errors.

The principle error is the gross lack of water applied to the footballs for their “Wet Football Model”.
Note that this is far from their only engineering error.
__


[End Part 2]

 

[tom.kordis]

[Part 3]

Background on the effect of moisture content in the leather of the football:

Every experimental investigator (including Exponent and me) has shown that the Ideal Gas Law accurately predicts the pressure drop due to changes in temperature for dry footballs.

At the same time, every experimental investigator (including Exponent and me) has shown that the Ideal Gas Law does not accurately predicts the pressure drop due to changes in temperature for wet footballs. Every experiment has shown that there is an additional pressure drop due to the moisture content of the footballs.

While noting that Water Exposure is one of the only factors which effects the equilibrium pressure & Warming Time Constant (see fig. 21, page 42 of their Appendix 1 to the Wells Report), Exponent’s incompetent error was to NOT parameterize the magnitude of this effect.

In essence, for any competent test protocol, one
identifies each pertinent factor (in this case, “water exposure”),
estimates the actual magnitude of the effect, (i.e., “to how much water were the Patriots & Colts balls exposed?”)
subjects their test articles (their footballs) to a range of effects that is guaranteed to bracket the actual exposure
repeats step 3 with a number of test articles, in order to test repeatability of results
determines from the above steps the sensitivity of their results to variations in the pertinent factor.

Exponent correctly performed step 1, and then incompetently ignored steps 2 through 5. They simply guessed at the exposure.
And they guessed wrong.

They guessed:
the exposure of the Patriots balls & the Colts balls was equivalent.
each Patriots ball was exposed to the rain only while it was “in play”.
spraying the Patriots’ balls with a spray bottle & then wiping it off with a towel (per note footnote 36 on page 42 of the Exponent Lab report (see below) provided sufficient moisture to model the actual water exposure.
That the temperature of the rain water was the same as the “dry bulb air temperature”.

Footnote 36. "For these and subsequent experiments a “wet” football was one in which a hand held spray bottle was used to spray a football with water every 15 minutes during the period simulating the first half of game play. The spray bottle with its contents was kept at the same environmental conditions as the footballs undergoing spraying. Each time the footballs were sprayed they were toweled off."

Each of these guesses was wrong.
As determined by interviews with each teams’ ball boys, while not “in play”, the Colts kept their footballs in plastic trash bags. The Patriots’ ball boys did not follow this practice. (See http://wellsreportcontext.com/) As a result, each Colts’ football was exposed to an average of (12:30 sec, game time, first half) * (3 minutes real time/minute game time) / 9 balls used = 4.3 minutes of rain exposure per ball. Each Patriots’ football accumulated moisture throughout the first half, resulting in 90 minutes of rain exposure per ball.
As described above, in the absence of the use of plastic trash bags while not in use, each Patriots’ ball was exposed to approximately 90 minutes of rain water.
Exponent’s spraying of their model for the Patriots’ wet balls once every 15 minutes & then toweling off (see the vague procedure description, above) grossly underestimated the actual water exposure of the Patriots’ footballs.
The rain water formed at altitude (likely 1,000 to 3,000 feet). The Temperature Lapse Rate for humid conditions is 3°F/1000 foot elevation. The rainwater was likely 3 to 10°F colder than the air temperature (50°F, then dropping to 48°F). The water that Exponent used to spray their footballs was set to the air temperature, not the rainwater temperature. This produced false results.

__

[End Part 3]

 

[tom.kordis]

[Part 4]

Proof that Exponent grossly under-wet their model of the Patriots’ Wet Football

The following graphs prove that Exponent’s “Patriots’ Wet Football Model” was flawed by its gross “under-wetting” of the football:

The following graph shows what the raw data of the Patriots’ football pressure should have been IF Exponent’s “wet football model’ had accurately reflected the Thermal Warming Time of the actual balls used by the Patriots in the AFC Championship game.

Note that, in this graph, the SLOPE of the Patriots pressure data vs. time accurately mimics the slope of Exponent’s “Patriots Wet Football Model”. Both slopes show a warming time constant of 0.101 psi/minute.

The pertinent question is “Did the Patriots footballs actually show this warming time constant?
The answer is “No, not even close.”

Here is the raw data:

Note that footballs 1, 6 & 7 (orange squares & orange dashed line) are the Patriots “Spare Balls”. Being unused in the game, they are significantly drier than the game balls. Note that their warming time constants are as expected, about 0.102 psi/minute.

Note also that (at 0.007 psi/minute) the slope of the Patriots Game balls (blue diamonds & blue dashed line) is far less than (about 15x less than) the slope of Exponent’s model for these balls.

These graphs do not “suggest” that Exponent under-wet the Patriots footballs in their modeling & testing.
These graphs prove that Exponent under-wet the Patriots footballs in their modeling & testing.

As proven by every experimenters’ testing (including Exponent’s), the fact that the Patriots’ footballs were “under-wet” also means that the Patriots footballs equilibrated to a significantly lower average pressure than Exponent’s model of their “Wet” football.

Since Exponent's “warming time constant” and the equilibrium temperature for the Patriots footballs are the FOUNDATION of their conclusions, and since their model of the Patriots’ wet footballs is erroneous, then their conclusions are simply wrong.

Mr. Goodell, you are encouraged to bring this memo to both competent engineers and to the engineers at Exponent and ask for a reply.

Competent engineers will agree with me.

The engineers at Exponent will not be able to provide a viable explanation for the difference between their model’s Warming Time Constant (as determined in figure 22, page 44 of Appendix 1 of the Wells Report) & the Patriots’ footballs actual Warming Time Constant (as determined by plotting the raw data, using the Wells Report estimate of the timing of the data (i.e., starting about 2 minutes & continuing for 4 to 5 additional minutes, after being brought into the Officials Locker Room).

If Exponent provides more junk engineering, I will be happy to review their reply and point out its errors.
__

 

[tom.kordis]

[Part 5]

You have one last opportunity to save yourself & your reputation.

I strongly urge you to grasp that opportunity & reverse all of the unjust penalties imposed in this case. Next fall will prove you correct if you follow this advice or incompetent if you choose to ignore it.

You also need to bring the NFL into the 20th century of measurement practices. This means instituting a simple set of procedures that follow the spirit of the engineering world’s ISO 9001/9002 standards.

This requires that the NFL:

1. get a competent person (i.e., a mechanical or chemical engineer) to change your pressure specifications.
   Note well: it is 100% impossible to tell the amount of air inside any football by measuring just the pressure. One must measure both the pressure and the temperature of the air inside the ball.
   Note well: the NFL’s current specifications for pressure (as currently interpreted) are utterly incompetent. It is not possible to follow them for any football game played in temperatures below 50°F or above 90°F.
   
   
2. Use only approved pressure & temperature gauges, which are frequently (e.g., 2x per year) inspected & calibrated.
   
   
3. Train all people who will be taking these measurements in the proper techniques.
   Note well: your report tells you that the people taking the pressure measurements have done so competently. This is a disgraceful lie. I invite you to check my assertion with any competent Manufacturing or Quality Control Engineer.
   
   
4. All measurements must be documented & records retained.

You can deliver the NFL from this pit of technical ignorance only if you follow the advice that I’ve provided, above.
Ignore it at your grave professional peril.

If you have any questions about any of the above, please feel free to contact me. I will be happy to explain it to you in detail.


Best Regards,

Tom Kordis

[End of Message]

 

[tom.kordis]

BTW, this message bounced.

Does anyone have a good email address for Roger Goodell & Troy Vincent?

 

[ChoWZa]

Did you try [email protected] ?

 

[hambone1818]

Tom, can I make a few suggestions? I also have a question for you.

First off, this is phenomenal work! I won't pretend to understand the science but the analysis sounds legit, and certainly Exponent has botched other aspects of the investigation, the 'spray bottle every fifteen minutes' experiment sounded incredibly wrong to me from the start so I'm glad someone looked into it.

Second,my question: the spare balls (1, 6 and 7), is that detailed in Exponents analysis? I don't remember seeing it. If so I would recommend you add a footnote linking to the page in the Wells report, the data laid out in the last graph is pretty telling if three off the Pats balls were out of the rain.

One suggestion is that you tone down the threats/rhetoric/ad hominem attacks. I would edit this to be as professional an analysis as possible, don't make your rooting interest part of the story at all. Stick to the science and only the science; you can highlight Exponents incompetence and bias in past studies but if the analysis comes off as biased/from a Pats fan will raise doubts from any non-Pats fan who reads this. I mean Volin attacked the AEI report because Kraft Foundation donated money once upon a time (which wasn't even Robert Kraft's foundation/company!), anyone reading this would see the vitriol and immediately discount the entire study (even if that's unfair).

I would also post this on the main board, let others read through it, help you tighten it up before sending it off. This is a great breakdown, it deserves eyes on it but I think it could really be stripped down to the science and let that speak for itself. Some other people may have suggestions/contacts they could hook you up with, but this should be on the main board to get the maximum exposure before it's sent off to the NFL.

Finally, I wouldn't just send this to the NFL. I'd get this out to Tom Curran, Ben Volin, Adam Schefter, Chris Price, Mike Reiss, Mike Florio, Felger and Mazz, D&C. Any and every media outlet, get it out there! This will likely be fought in the courtroom but it's also being fought in the court of public opinion. The AEI report got some serious traction, it's helped change the narrative just a bit and at least make it known to anyone who'll listen that Exponent did bad science. This would put another serious dent in their report. The more people hear about them using a spray bottle of room temp water to simulate driving rain the more they'll realize how bad the analysis was.

Great work either way, thanks for putting the time in to debunk the crap spewed by Exponent!

 

[DB01]

Hi Tom,

It is obvious that you have put a lot of thought into this assessment and I commend you for your work.
Your logical and scientific analysis seems to hold up as well.

You make a good point about some TV broadcasters next year trying to repeat the Pats/Colts game football conditions. This will spark some people's interests and will cast doubt on the NFL's intelligence.

However, I note a few issues with your approach and letter.

You are making what I call an "Engineer's argument" to lay people and that will not work.
I learned this years ago at the beginning of my engineering career.

You must make the information extremely simple to understand and you must do it with colorful charts that are also very easy to understand and then relate it to their personal experience.

Do it with one chart and three bullet points and you will have a chance that lay people will understand this.

Finally, be tactful with your opinions. Help them to come to their own conclusions. "...The most profoundly incompetent buffoons in Sports History" statement is not helpful.

Give it a shot...........

I wish you the best.

 

[MassPats38]

I would agree with hambone's comments on tone, Tom.

Any reference to motivations and agendas calls your own into question. As an engineer, point out the flaws in modeling in clear, non-scientific speak. Assumptions in modeling are sound or unsound. Point out the variance in results from poor assumptions. The tone should be neutral and objective if it is scientific. I don't expect a technical report would attempt to ascertain builder motives in a request or demand. Just say why the request or demand works or doesn't work scientifically.

The premise is the expert conclusions are incorrect. Support that with the reasoning in a coherent and easily readable format (supported by equations and correct calculations) and you will find out if this is motivation/agenda driven. If it is so driven, then frankly a sharper tone will not change the course of this. That has already been tried in news articles, yet here we are. Less is more if you can explain yourself objectively and coherently.

 

[ChoWZa]

Also in the interest of proofreading:

At the same time, every experimental investigator (including Exponent and me) has shown that the Ideal Gas Law does not accurately predicts the pressure drop due to changes in temperature for wet footballs.

 

[tom.kordis]

Thanks, guys.
I'll rewrite it ASAP.
And make sure there aren't any speling erorrs.

Right now, I'm heading into the Sierra Nevada mountains for a couple of weeks of vacation. I'll incorporate all your suggestions before sending it off. Hopefully in the next day or so.

You guys are all buzz-kills, with regard to my engineering snark, tho...


It's especially annoying because you're right.

 

[tom.kordis]

Did you try [email protected] ?

Yup, I tried that one.
No joy.