Does Stephon Gilmore get fewer flags with New England Patriots than he did with Buffalo Bills?

As a team of writers who are first and foremost fans of the Buffalo Bills, I’d wager that Buffalo Rumblings is a place that can appreciate the inquiries of other fans. One recent musing that crossed our paths wanted to explore the idea that the New England Patriots are treated differently by the refs. Courtesy of Michael Buckenmeyer, the idea was to filter this notion via a former penalty-prone Buffalo Bill. Here’s Michael’s pitch...

Love the site. Just a question that maybe one of your writers can look into. Do you know if there have been any major differences in the number of defensive holding/PI penalties called on Gilmore since leaving the Bills for the Pats?

I remember that when we didn't re-sign him, I was able to rationalize it to myself because I remember how often he would be called for huge holding or PI penalties at critical moments while on the Bills. Just curious, now that he is on the Patriots if he is getting preferential treatment.

This is a request we can handle for sure. Will there be tables? Yeah. There are tables.

Stephon Gilmore Penalty Counts

Full disclosure, I elected to go with all penalties for Gilmore. More than half are pass interference and holding calls for the record. However, with the idea of preferential treatment, the refs should have influence over face mask, roughness and other calls and the full data set should lead to better conclusions. Seasons with Buffalo are in red/pink above the dark black line. Patriots seasons are below.

Gilmore’s average flags per season right away suggests he hasn’t benefited whatsoever from being a Patriot. With one season below his average of 8.4 and one above it’s a wash. If you’re wondering, his average when separated by team is nearly identical.

Average accepted flags does show a little improvement in New England, making the case that there could be some bias. However that’s a risky proposition as in order to negate a Patriots penalty they either need to coordinate an offsetting penalty or convince the opponent to decline somehow. More than likely this is merely the result of Gilmore’s rookie year. Not only was this his highest flag total, but he had zero offset or declined, which is a major anomaly.

Yards are included just for fun, as defensive pass interference is highly volatile when it comes to yardage. Even still, it’s basically a wash for Gilmore between the two teams.

Stephon Gilmore penalty rates

That really shouldn’t be the whole story. If we’re being fair to Stephon Gilmore he’s had a few extra games in his two seasons with the Patriots. If his penalties are similar but he had more opportunity to play, that should mean he has actually cut down on penalties. Let’s adjust a couple ways.

I’ve already put it out there that declined and offset shouldn’t indicate preferential treatment from the refs so we’ll be using total penalties from here on out. When we adjust by number of games played both of his seasons with the Patriots do come out slightly below his personal average. The numbers suggest he hovers around one penalty every other game and several of his seasons with the Bills also fall below the 0.6 flags per game average.

Adjusting even further, we can examine snap counts. If every play represents a penalty opportunity this should provide our best rate metric. For this measure, the more meaningful number is to invert the formula. What this means is higher numbers are good as the number represents how many plays occur (on average) between a Stephon Gilmore penalty. This, too, shows a slight advantage for his seasons with the Patriots. The 2018 season is basically perfectly average, but in 2017 he was a good deal better than his average with 152 snaps between penalties.

Summary

So, is there evidence of preferential treatment? I don’t believe so. Examining his rate by snap count he’s remarkably consistent, with most of his years falling between 111 snaps and 140. While the 2017 season is a bit out of whack, it’s only one penalty away from being within his typical range. It’s an anomaly but not one that jumps out. His rookie year stands out as the largest anomaly and pulls the averages up for his seasons with the Bills. The rate metrics show a slight edge to the Patriots years, but are difficult to rely on when trying to make a case for preferential treatment.