The mods felt the need to delete my post so here it is as a comment:
Pete Morelli Statistical Analysis
There's a lot of buzz about Pete Morelli's supposed anti-Eagle bias, so I thought I'd whip up a quick analysis to determine whether or not Pete and his crew are truly biased against the Eagles (spoiler: they aren't).
Source Data:
I used the "Games" table from https://www.pro-football-reference.com/officials/MorePe0r.htm#header, and trimmed out all games where Pete was a Field Judge, so I could focus only on the games where Pete was a Referee.
Methodology:
I performed OLS four times, once for each dependant variable (# of home team penalties; # of away team penalties; home team penalty yards; away team penalty yards). The dependent variables consisted of 64 dummies, one for each team home and away.
Analysis:
A home team playing against the visiting Eagles can expect 1.55 fewer penalties than if they were playing against the 49ers (my stats software decided to use the 49ers as a baseline). This isn't a statistically significant result however, as the standard error on the value of 1.55 is also 1.55, meaning there's a 32% chance the home team actually incurs more penalties than they would had they been playing the 49ers. This means that there is no bias towards the Eagles' opponents when the Eagles are playing on the road. In fact, Pete and his crew are not biased towards any team in this manner.
The visiting Eagles team should expect 1.72 fewer penalties than a visiting 49ers team. However the standard error is 1.79, so there's a 34% chance the visiting Eagles team actually incurs more penalties than the 49ers would. There is no bias against a visiting Eagles team.
When the Eagles are at home, they should expect to incur 1.23 more penalties than they would if they were the Giants (different regression so my software picked a different baseline). The standard error however is 2.22, so there's actually a 58% the Eagles incur less penalties at home than the Giants. NO BIAS.
When the Eagles are at home, their opponent should expect to incur 1.29 more penalties than if they were at the Giants. However the standard error (2.57) is once again very large. There is 62% chance that the opponent would actually incur fewer penalties against they Eagles than they would against the Giants. NO BIAS!!
So there is no bias against the Eagles as far as the number of penalties is concerned. But what about the severity of penalties? Let's take a look at the penalty yards.
A home team playing against the visiting Eagles can expect to receive 22.9 fewer penalty yards than if they were playing against the visiting 49ers. However with a standard error of 14.0 there remains a 10% chance that the bias doesn't actually exist. 90% chance of bias towards the Eagles' opponent if the Eagles are on the road is our strongest result yet, however normally we like to see 95% before we call something statistically significant (and even that's pretty weak in my personal opinion). Medium levels of bias.
The visiting Eagles team should expect 14.9 fewer penalty yards than if they were the visiting 49ers. Standard error if 18.3, so there is a 42% chance of the bias being in the opposite direction. This is not even close to being statistically significant. NO BIAS.
When the Eagles are at home they should expect to receive 3.4 more penalty yards than if they were the Giants playing at home. The standard error of 20.0 makes this result statistically irrelevant. NO BIAS.
The visiting team playing against the Eagles at home should expect to receive 16.2 more penalty yards than if they were visiting the Giants. The standard error is 26.2, so this too is statistically irrelevant. NO BIAS.
Conclusion:
It turns out Pete and his crew do not have an anti-Eagles bias. The strongest result we obtained pointing towards a bias weakly suggested Pete is likely to go easy on the home team which the Eagles are visiting.
Interestingly enough, although there was no significant bias for or against the Eagles, there are several statistically significant results obtained from the data. The following biases pass the 95% confidence level:
The following teams incur abnormally low numbers of penalties and penalty yards when on the road:
Bears
Colts
Jaguars (penalties only)
Chiefs
Patriots
Jets
All that being said, the probability of us incurring 10 or more penalties last night was 9.34% under the assumption of no bias.
The probability of the Panthers incurring two of fewer penalties last night was 9.01% under the assumption of no bias.
The probability of us incurring 9 or more more penalties than our opponent was 0.82% under the assumption of no bias.
Seems like bias right? The catch is that over the course of a 224 game sample size, games like this are expected to happen almost twice. So we just caught an unlucky game, nothing more.
TL,DR:
Pete Morelli and his crew are biased towards some teams, just not the Eagles (sorry guys).