The War on Tom Brady
A new report on the NFL’s “Deflategate” controversy – by statistical experts at the American Enterprise Institute – confirms much of what I had detected regarding flaws in the NFL’s findings, which claimed the New England Patriots had probably deflated their footballs and that quarterback Tom Brady probably had some awareness. AEI concluded that physics – not tampering – could explain the changes in air pressure.
AEI’s principal observation was that the NFL’s investigators were mistaken in relying on footballs used by the Indianapolis Colts in the same game as a control group, i.e., an assumption that they were otherwise identical to the Patriots’ footballs and that any deviation from the Colts’ air-pressure measurements would indicate wrongdoing by the Patriots.
The key flaw in that assumption was that the checks on the air pressure of the Colts’ footballs came at the end of halftime – when the footballs had been indoors at a warmer temperature and thus had naturally re-inflated – while the Patriots footballs were checked at the start of halftime when the effects of the cold, rainy weather would still have depressed the measurements.
As the AEI economists wrote, “Logistically, the greater change in pressure in the Patriots footballs can be explained by the fact that sufficient time may have passed between halftime testing of the two teams’ balls for the Colts balls to warm significantly, effectively inflating them.”
To downplay this key variable in the NFL’s report, outside counsel Ted Wells sought to compress the gap in time between when the air pressure of the Patriots’ footballs was measured and when the Colts’ footballs were tested. Wells asserted that the measurements followed one after the other, but other evidence – and conflicting recollections by the NFL officials involved in the testing – suggest that the Patriots’ footballs were tested and then re-inflated before the officials turned to the Colts’ footballs, measuring only four because they ran out of time.
As AEI and I both noted, a key piece of evidence undermining Wells’s compressed chronology was that the two NFL officials involved in testing the footballs seemed to have switched gauges between the first set of tests and the second, which would have made little sense if the measurements were sequential rather than separated by the re-inflation of the Patriots’ footballs.
But, as I have noted, there was another reason why the Colts’ footballs should not have served as a “control group” – because the two sets of footballs were conditioned differently before the game. The Patriots rubbed down the balls more thoroughly than the Colts did, thus making the Patriots’ footballs less water resistant. The NFL’s scientific consultants found that moisture as well as temperature affected changes in air pressure and the duration of declines in pounds per square inch [PSI]. But Wells did not take into account that variable either.
Beyond these football variables, AEI detected an irregularity in how the Wells report presented its scientific findings, saying: “our replication of the report’s analysis finds that it relies on an unorthodox statistical procedure at odds with the methodology the report describes.” In other words, Wells seems to have played some games with the statistics to reach his conclusion incriminating the Patriots.
The AEI report noted another “crucial piece of evidence … overlooked in the [Wells] report’s analysis” relating to the one Patriots’ football that was intercepted by the Colts during the first half. It became the basis for the Colts’ allegation that the Patriots had under-inflated their footballs, but the AEI report said:
“Assuming that the intercepted Patriots ball that was tested was inflated to 12.5 PSI [the minimum legal standard favored by Brady] before the game, the average of three measurements derived by this separate measurement process (11.52 PSI) was at the top of the range implied by the Ideal Gas [Law], according to the Wells report.”
In other words, the assumption that started this whole controversy – that the Colts thought the intercepted ball had been intentionally made softer than it should be – was mistaken. The ball’s PSI fell within the expected range as predicted by the laws of physics.
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