A few months ago I wrote a small piece about the NFL’s Deflategate controversy where I questioned the conduct of the NFL with respect to the entire Deflategate affair (see article here). The questions I raised concerning how the NFL and its officials handled the affair before the incident in question, during the game in which the supposed incident occurred, and afterwards remain unanswered, but recently two related incidents have given me cause to revisit what has transpired. The first incident was Tom Brady’s appeal of his suspension which was heard yesterday which of course makes this posting topical, and the second incident was the publication by the American Enterprise Institute of their analysis of the Wells Report. (See AEI Report here)

For those who do not know, the Wells Report was the investigative report provided to the NFL by Ted Wells which served as the basis for the NFL pressing forward with its punishment of the Patriots and Tom Brady for Tom allegedly (more probably than not) being involved in a scheme to deflate footballs just prior to their 2015 Conference Finals Game against the Indianapolis Colts.

The amazing conclusion of the American Enterprise Institute Report is that it is unlikely that the Patriots deflated the Footballs. The report casts serious doubts not only upon the interpretation and methodology used by Ted Wells, but also upon his  factual understanding of the underlying statistical analysis used in the report.

This might all be small news, except the American Enterprise Institute is the same body which provided a testimony to former National Football League (NFL) Commissioner Paul Tagliabue regarding the Bountygate scandal. Their testimony was reported to be a contributing factor in his decision to withdraw penalties against the New Orleans Saints players involved.

With respect to the Wells Report, The AEI analysis makes several startling revelations:

1) The Wells Report relies on unorthodox statistical procedures which were inconsistent with the actual statistical methodology the report describes.

The Wells Report’s conclusions are based primarily upon air pressure measurements of the footballs before the game and at halftime. What complicates things is that the NFL officials had two different pressure gauges which might have been used. These each gave slightly different readings. Even though the NFL official in charge reported using a specific pressure gauge before the game, Wells concludes he must have used the opposite gauge. The conclusions drawn from the Wells Report’s statistical analysis hinge heavily upon which gauge was actually used before the game and which gauge(s) were used at half time. Wells appears to believe his analysis takes all of this into account; unfortunately the math does not back this statement up.

2) In interpreting the results, the Wells Report failed to take into account other reasonable scenarios which would explain the findings.

Basically the report investigated only whether the evidence supported that deflation of New England Patriot footballs had occurred relative to the Indianapolis Colts footballs, and concluded that this relative deflation when it was found was evidence of tampering. It did not take into account an equally plausible theory that instead the Indianapolis Colts footballs may have been showing anomalous inflation. It turns out that the AEI report concludes that this was more likely scenario, and it suggests that this over inflation was caused not by the Colts, but through inconsistent treatment of the footballs by NFL staff when they were measuring the air pressures.

3) The Wells report ignored the predictions of the Ideal Gas Law and the basic physics of inflation and deflation relative to temperature change. 

It turns out that when basic physics is applied to the understanding of how footballs would inflate or deflate relative to temperature and ambient air pressure, the amount of deflation which was noted to have occurred with the New England Patriots balls was pretty much what science would have predicted given the circumstances. It also turns out that the Indianapolis Colts Footballs did not show the amount of deflation which would have been expected given the outside temperature. The AEI report concludes that the most reasonable explanation for this was that when all of the balls were tested during halftime, the Patriot balls were tested at the start of halftime when the footballs were still cold, and the Colt footballs were tested afterwards, after they had warmed up in the locker room. This hypothesis was backed up by the admission in the Wells Report that all of the Patriot balls were tested first (which would have been at the start of halftime), and that they had time to only test four of the Colts balls because halftime had ended. The AEI report states that allowing the Colts balls to warm up in the locker room by as little as fifteen minutes more than the Patriots balls was the probable cause for the relative inflation of these balls relative to the colder Patriots balls.

4) It is unlikely that the Patriots deflated the Footballs

The American Enterprise Institute Report concludes as follows:

The fact that the average pressure of the Colts balls was significantly above the prediction of the Ideal Gas Law, while that of the Patriots balls was not, is inconsistent with the findings of the Wells report. Our conclusion that the warming of the balls during halftime is the key factor overlooked in the Wells report is supported by the observation that the reading of the intercepted Patriots football, measured separately from the other Patriots balls, came in almost precisely at the prediction of the law. Under the hypothesis asserted by the Well report, the odds of this Patriots ball matching the Ideal Gas Law prediction were between 1 out of 3 and 1 out of 300. It is therefore unlikely that the Patriots deflated the footballs.