Thursday, July 30, 2015

An Economist Looks at Deflategate

The Data in the Wells Report
By Russell Roberts

I’m biased. I’m a Patriots fan. I wanted the Wells Report to exonerate the Patriots, their staff, and their quarterback. It did not. The question remains as to whether it’s accurate.

There are many damning facts in the Wells Report. Texts. Unexpected bathroom adventures. A reference to a needle and a reference to a deflator. Are there innocent explanations for those facts? Maybe.

But it wouldn’t surprise me in the least to discover that Brady encouraged Patriots employees to push the envelope on the low side of the legal psi limit. He apparently likes the ball softer than harder. Maybe they had an “understanding.” No smoking gun, no explicit texts, but winking and nodding. Very possible. Maybe “probable” or “likely” as the Wells report concludes. There’s circumstantial evidence pointing that way. (And if there was any evidence pointing in an opposite direction, the Wells Report chose not provide it.)

But as a data guy, I’m interested in the data the Wells Report provides and whether it reinforces the circumstantial evidence. What I’ve tried to do here is bring out some issues I have not seen discussed elsewhere related to the data. We’re going deep into the weeds.

Read the rest here.


  1. There's another important possibility that undercuts the Non-Logo argument even more. It is entirely possible that Anderson inattentively changed gauges between measuring Patriot and Colt balls - as happened at halftime even under heightened scrutiny. This reconciles the measurements almost completely. And it also means that similarity between pregame Colt measurements and Anderson's measurements is moot. This leaves the NFL's argument as, in effect, that it is extremely unlikely that the Patriots would use a gauge that was as far off as that used by an NFL referee in a championship game. Odd logic.

  2. It's interesting to me that Russ chooses not to mention the halftime readings of the Colts footballs. The average variance between 12.5 PSI and the halftime reading of the 11 Patriots footballs was -1.39 and -1.01 for Blakeman and Prioleau respectively. The average variance between 13.0 PSI and the halftime reading 4 Colts footballs was -.38 and -.56. Even when choosing the four Patriots footballs with the smallest variances, they still exceed that of the Colts footballs.

    Until someone can convince me that weather caused the Patriots balls to deflate more than Colts balls, I still think this is pretty damning evidence. I'll concede however, that there is no smoking gun, so without any actual proof, the penalty may be a bit harsh. Further, the balls, deflated or not, had no bearing on that particular game. (Full disclosure: I'm a Colts season ticket holder and despise the Patriots)

  3. Reading error, calibration error, process error, drift, tolerance, etc... and they're reporting measurements to within one hundredth of a psi. I doubt that the pressure gauges used in those field conditions could be counted on for an accuracy of +/- 1 psi.