DeflateGate: The Wells Report Crumbles

As time goes on, the more the Wells Report crumbles.  Despite some significant scientific work***, it is clear now that the statistics are suspect, there are unexplained variations in ball pressures which just don’t make sense with a systematic attempt by an individual to lower the pressure for the benefit of a quarterback,  there are large variations in wet/dry ball pressures that are improperly accounted for and might be attributed to evaporative cooling,  and the Wells Report investigators failed to account for pressure drops in some of the Patriots ball pressures due to the long final drive up the field by the Patriots played on a cold turf field.

Their original conclusion is negated.  It can no longer be said that it is “probable” that the Patriots cheated.  The combination of these problems in the scientific analysis make it highly unlikely that cheating of any sort went on.

This result is easy to check.  Next year, or some year in the future when the weather conditions and field conditions match those of the Patriots-Colts game, just measure the halftime pressures.  This would be a “real game time simulation”, not the simulation cooked in an LA lab, which missed important game time factors. This would be the ultimate vindication, and unless the NFL changes its tune immediately, they will have to explain how they could have been so wrong.

The Statistics

Using p-values like the Wells Report does, only makes sense if you can control for all the variations in the history of two populations, in this case the Colts’ footballs, and the Patriots’ footballs.  There are three large questions that suggest that the control did not exist:

1. We don’t know which pressure gauge was used to measure the two populations. (This they worked to account for.)

2. Whether a ball is wet or dry is shown to significantly impact the rate of warming, and the starting temperature.  We simply don’t know if the small sample of measured Colts’ balls were dry or wet, and we don’t know how long each population was allowed to warm inside the locker room before measurement.  Even the Wells Report experiments show wide unexplained variations in the pressures of wet and dry balls depending on which of their experimental charts you look at.  And we have also found out independent of the Wells Report, that the Colts’ balls were kept in trash bags to keep them dry, the Patriots were not.  The Colts’ balls simply cannot be used as a control in this situation.

3.  Some of the Patriots balls spent more time on the playing field just prior to the half time measurement because of a lengthy Patriots drive up the field.  There is strong reason to believe that the field was significantly colder than the air temperature, and would have caused cooling on those balls.

And even with this uncertainty, another uncertainty involves the way the Wells Report scientists computed their statistics.  While they knew the ball pressures were rising in the locker room, they chose to use the stats from the starting pressures.

As many people have now pointed out, just points 1 and 2, coupled with the way the scientists computed their statistics is enough to render any conclusion other than “inconclusive” impossible.  With all three, the conclusion is completely negated.

In their “Game Day Simulation”, the Wells Report forgot to include the Game.

The 2015 AFC Championship Game was played on a cold artificial turf field, which caused wide variations in the Patriots football pressures measured at half time.

The Artificial Turf was colder than the air temperature, and during the game balls sitting on the cold turf at the line of scrimmage during the would have cooled off more than other balls.  In particular a number of Patriots balls were rolled around and sat on that wet cold turf during that long final drive leading up to halftime that included 4 timeouts after the two minute warning.  That drive, and the colder temperature explains the scatter in pressures seen in the Patriots footballs, as well as the lower average pressure.  This effect was not considered by the Wells Report Investigators.  (see  for details)

That the Artificial Turf was cold must not have been obvious to Wells Report Investigators in LA.  However, to us who live in New England, we can remember that during most of January, the temperatures hovered at or below 20 degrees, but on that one day of the AFC Championship, the temperature jumped from well below freezing in the morning to a balmy but wet 50 degrees at game time.  The sub-freezing ground and sand under the field would not have had time to warm up, and would have still been at a 20 degree to 25 degree temperature.  Turf fields are designed to bring their cooling power to the surface, so the ground would have been significantly colder than the air.  Moisture collecting on those artificial grass blades would have been cooled, and that cold moisture would have been transferred to the balls by contact.

This is not an effect that can be ignored.  It is not an effect that can be simulated by spraying air temperature water onto the ball every 15 minutes and then wiping it off. (This was the Wells Report attempt at simulating the game). This is an effect that could easily have lowered the Patriots measured average ball temperature by .2psi to .6psi, which by everyone’s determination is more than enough to vindicate the Patriots.

Evaporative Cooling — The Difference Maker between Wet and Dry Balls

Another effect is evaporative cooling, which should have been more obvious to the LA investigators.  Indeed, you can see it in the results of several of their charts in the report itself, one where it appears as a .1psi shift in pressure, another where it is closer to a .2psi shift,  and another where it appears as a .5psi decrease in pressure of a wet ball.   Which is it?  Or, on the actual day in question, was it even more, and did it depend upon how the balls were handled? And why isn’t this mentioned as a uncertainty in the actual results?  The scientists obviously noticed it, but did not explain it or try to control for it. Some of the Wells Report scientists would do well to consult a psychrometric chart, and see how dramatic those effects really are, and actually use them to predict the warming and cooling patterns for the wet and dry footballs.  In actual fact, the wet balls should have barely changed in pressure when brought back into the locker room.  At a temperature of 72F, and humidity measuring 20%, the wet-bulb temperature is 50F.  If the balls were at 48F (which they were not, because of other factors), then only a 2 degree shift (about .1psi) would have occurred.

Patriots Exonerated

The Physics done by the Wells Report investigators, combined with the missed fact of a cold field on which the Patriots balls sat during the game, uncertainty about wet and dry balls, and questionable statistics removes most any doubt of the innocence of the Patriots.  We no longer have to accept the bizarre and unlikely scenario of a locker room attendant casually entering the bathroom, deflating random amounts of air from some but not all of the balls, and emerging 90 seconds later as if he had just been to the bathroom for the usual reasons.  If in fact he did remove some air, it was already small without the consideration of the cold field, and with that consideration it must have been negligible, or perhaps he even added some air.

As Physicists we have done our jobs and explained the facts of the situation.  The weather can be held responsible for the ball pressures.  We can no longer accept the label that it is “probable” the Patriots cheated “unless some other unforeseen conditions are found” as given by the Wells Report.  A least a couple of unforeseen conditions for the Wells Report has been found, and there is nothing more to be said.

Beyond the Physics

From here it should be simple.  However, it is not.  People have moved beyond the consideration of physics. It has long become a struggle between public opinion, an atmosphere of suspicion promoted by the NFL leadership,  people and press who have staked their reputations on the guilt or innocence of Tom Brady, and just a bone weary public who doesn’t want to hear any more.  Despite the truth of the science, what matters now is the perception of truth held by the football commissioner who has placed himself in the uncomfortable position of being judge, jury, and executioner despite his own lack of knowledge of science.  And he has his own personal stake in the outcome.  He has accepted the Wells report as gospel truth and has already acted on it, without protecting himself or the NFL with an independent process for verifying the report, or even appealing its validity.  Even though an apology is called for, he himself would look foolish coming forward with it now.

The Future

There is one other fact about Physics which may ultimately carry the day.  It doesn’t change.  It can and will repeat itself.

It is a problem for the NFL that this scenario (the set of weather conditions — frigid temperatures leading up to a relatively warm 50 degree rainy afternoon) may repeat itself next year at some other field, and for a different set of football teams.  If someone on one of the teams complains about football pressures, and they are measured more carefully at halftime,  will the same punishments be imposed as were done this time — maybe to both teams?

The legacy of this NFL leadership is at stake.  Will they be remembered as the leaders who seriously handicapped the top team in the NFL for the next season?   Will this put an * beside any team that wins the AFC, or perhaps even the Superbowl, to say they won, but they were mistakenly given a leg up by the NFL commissioner to get there?

Or will the NFL admit their mistake, publicly apologize, and quickly right the situation?  And then they have some work to do at the NFL to make sure processes are in place to insure fairness to individuals both on and off the field.  Yes– guilty parties should be dealt with swiftly and severely, but there should be a way to appeal for a TV replay to make sure the correct call was made.


*** The Wells Report Scientists did try to do a complete and thorough job.  That is evident from their report.  However, as is often the case in scientific endeavors, other scientists review the work, and find problems that should be explained or taken into account.  That did not happen here, or at least is only now happening haphazardly through the press.  It was the process that was flawed, not the scientists, and the best that can be said for the Wells Report is that it is based on an inconclusive and incomplete scientific analysis.

If a similar problem occurs in the future, it will be important for the the NFL to develop different processes to avoid jumping to incorrect conclusions.  In this case, this led to the NFL to try to shoehorn this data onto a bizarre theory of deflated footballs, a nefarious locker room attendant, cryptic text messages, and a 243 page confusing explanatory report, rather than letting the facts themselves lead to a more natural theory that fit the facts — i.e. the weather did it.


Some more references:

Three Key Areas Where the DeflateGate Report is Blinding us with Science



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