January 21, 2016


Deflategate, one year later: The anatomy of a failed controversy (MICHAEL MCCANN, Jan. 18, 2016, Sports Illustrated)

The controversy that became known as Deflategate started when Colts linebacker D'Qwell Jackson intercepted a pass thrown by Brady in the second quarter of the AFC championship game. Colts personnel believed the football seemed a little light, and when an intern measured its air pressure, he found the intercepted football to be less than 12.5 pounds per square inch or PSI, the basic unit for measuring pressure. This was significant since NFL rules require that game footballs fall within a range of 12.5 to 13.5 PSI. Those rules also assign a minimum penalty of a $25,000 fine to those who tamper with game footballs' air pressure and other qualities. The NFL regulates the PSI of footballs to ensure uniformity in how games are played and, although many football players downplay its competitive significance, slightly under-inflated footballs may be easier to catch.

Colts officials then alerted the referees about the intercepted football's air pressure and the referees in turn alerted NFL officials. Referees and league officials then tested the same intercepted football three times, yielding results of 11.45 PSI, 11.35 PSI, and 11.75 PSI. The league then ordered that the Patriots' other 11 footballs be tested at halftime; four Colts footballs were also tested at that time. While two different types of gauges were used and produced inconsistent results, all 11 of the Patriots footballs and three of the four Colts footballs measured under 12.5 PSI. The footballs were then re-inflated and used in the second half. Brady actually performed better using the re-inflated footballs, completing 12 of 14 passes.

The ball deflating was not terribly surprising, given that the game was played in weather conditions--cool and rainy--that tend to cause footballs to lose pressure. Even in good weather, footballs lose pressure as they are used. Indeed, as Massachusetts Institute of Technology Professor John Leonard has demonstrated, the PSI measurements taken at halftime are consistent with Ideal Gas Law, a basic scientific formula used to measure pressure when temperature, volume and number of gas moles are known. His findings are consistent with the findings of others, including data scientist Nick Kistner, three authors at AEI and University of New Hampshire science professors Michael Briggs and Martin Wosnik.

Posted by at January 21, 2016 9:59 PM