
As an NFL fan, (and a fan of the Seattle Seahawks in particular) I occasionally find myself watching football with my dad, and whenever I do, the accusation inevitably creeps in that the referees are biased in the way that they make penalty calls – specifically that for a given illegal action, a penalty flag will be thrown against the Seahawks much more frequently than against the opposing team, even when the offending action is performed at a similar rate by both teams. Personally, I’m not good enough at spotting every penalty on the field to say with confidence whether or not this is the case, and to be honest, my suspicion is that this feeling of one’s own team being unfairly persecuted is one harbored by most sports fans regardless of the team they root for. It occurs to me though, that as a data scientist, this sports fan is uniquely qualified to actually grab some data and attempt to vet this theory as it applies to my own team and be able to say with some objective numbers how well founded these suspicions may be.
The accusation at the heart of this study really has to do with penalties that are not called, for which there is no record, which makes this claim very hard to definitively confirm or refute. However, data on called penalties is published and publicly available, and through thoughtful analysis of the penalties that were called, we can at least see if there is any evidence of a bias towards calling penalties against certain teams more often than others.
Continue reading