Rethinking NFL Home Field Advantage Part I

NFL Home Field Advantage by Referee

Arrowhead Stadium - Wikipedia

As many have learned through our studies and advanced analytics, home field advantage (HFA) exists in all sports, but is largely due to referees and their (subliminal) human nature. You can learn about this phenomenon in detail on the podcast about Home Field Advantage by Freakonomics.

With that being known, many if not most NFL prediction models, and even MOST IMPORTANTLY Vegas lines assimilate that advantage to a particular stadium/typical crowd. That is, “Soldier FIeld Stadium has a stronger HFA than whatever College stadium the Chargers play at” instead of, Team A has a strong HFA this week because Ref Y has been assigned. If the Freakonomics’ study was and has been proven to be true, then why don’t we “tie” HFA to particular referees (vs. stadiums/crowds)?

RULE: Home Field Advantage exists in NFL. It has been proved its largely a function of the human nature of referees. Yet, books and many analysts still “price” HFA by stadium, not (human) referee.

We combed through the entire database of referee results, and below you will find a ranking of current NFL referees, based on the coefficient of variation of career, relative penalties called on away teams (vs. home teams) compared to the average referee. Coefficient of variation is a stat that encapsulates both average and consistency in one metric (Average/Standard of Deviation).

Strongest Home Field Advantage by NFL Referee

T PodrazaG SteedC JohnsonJ WalkerA EckS HochuliA JeffriesJ JenkinsT SymonetteB NealeC Hill
AVG-0.02-0.02-0.02-0.03-0.04-0.03-0.02-0.01-0.01-0.01-0.03
L5-0.03-0.02-0.02-0.03-0.04-0.02na-0.01-0.03-0.01na
stdev0.030.030.040.030.040.040.020.030.030.030.01
COV-0.68-0.59-0.51-0.99-0.87-0.63-0.82-0.48-0.41-0.45-2.04

Second Level best HFA by NFL Referee

J SeemanT MilesT CorrenteD ShawT HillK WashingtonG BradleyD McKenzieR MartinezA Hill
-0.01-0.01-0.01-0.01-0.01-0.01-0.01-0.01-0.01-0.01
-0.01-0.02-0.010.00-0.02-0.020.00-0.010.00-0.03
0.030.040.030.040.030.030.040.040.040.04
-0.34-0.31-0.30-0.27-0.26-0.26-0.25-0.24-0.21-0.16

Note, anything we try to discover is with the “Holy Grail” in mind. A predictive, causal variable NOT captured and priced into betting lines. I assure you this new way to look at HFA matches that criteria. We are using this (tied with an advanced look at stadium-based HFA) form of HFA in our week x model. You will see the variable included in our weekly predictions.

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