NFL home teams are winning at an unprecedented rate, and it’s 100% due to the replacement officials home bias.
Strong Home Field Bias
There historically has not been any home field bias under regular refs:
1) Home teams the last 10 yrs are exactly 581-581 ATS (50%) the first 8 weeks of the season. So far in 2012, they are 61% ATS (an increase of 11%). The fact that replacement referees allowed home teams to cover 11-4-1 ATS (73%) of the games in week 2 represents an increase of more than 2 standard deviations above average as compared to the last 3 seasons. In layman terms, this means only 2 out of 100 weeks would we see home teams cover 73% of the time, and that just so happened the 2nd week of the replacement referees. This is a potential fundamental change and a red flag.
2) Home teams the last 3 years have seen the exact same number of penalties enforced as road teams (194 penalties accepted per week on home teams & 195 penalties accepted on road teams). In other words, it’s usually about even each season. (Expanding from 2000-2011 there are just under 7% more penalties enforced on road teams vs. home teams). So far in 2012, they called 231 penalties accepted on road teams and only 188 accepted on home teams. This is a delta of 43 penalties, and means road teams have to deal with 23% more penalties. Already in 2012, we’ve had 43 more called on road teams. If calls at this rate continues, we will have 344 MORE penalties accepted on road teams than home teams this season!
Affects of the Home Field Bias
14 of the 16 home teams last week won their game. That marks the first time since the league expanded to 32 teams that 14 home teams have won in a single week.
Since 2002, teams who lost SU/ATS on the road in week 1 and play at home week 2 went 26-34 ATS (43%), failing to cover by an avg of 1.6 ppg. In 2012, teams who lost SU/ATS on the road in week 1 and played at home week 2 went 6-0-1 ATS (100%) and covered the spread by an average of 12.7 ppg.
So how should you, as a bettor, account for this? First, let’s examine exactly what they are and are not doing differently:
Penalty Trends in 2012
We know the replacement refs are enforcing 23% more penalties on road teams than home teams to start the season, a much higher number than average.
In terms of yardage, we’ve had almost 2,000 penalty yards enforced on road teams. This number is much higher than the season average called on road teams of 1,626 yds the last 3 years.
The penalty increase is mainly confined to 3 key calls:
Defensive Pass Interference: There have been 40 accepted DPI penalties thru 2 weeks of 2012. The last 3 years, the average per week is just 12. Thus, we are seeing an increase of 8 more calls per week.
Offensive Holding: There have been 72 accepted OH penalties so far this season compared to a 3 yr average of just 27 penalties. This is an increase of over 9 OH calls per week.
Personal Fouls: There are usually 3 personal fouls called per week, but so far this season we have seen 15 flags thrown for personal fouls. This is an increase of almost 5 per week.
There are a few key areas where there are fewer flags:
Offensive Pass Interference: There have been just 6 flags per week called, vs an expected 9 thrown based on the last 3 years.
Illegal Contact: There have been just 7 flags per week so far in 2012 as compared to over 9 expected the last 3 years.
Unnecessary Roughness: Officials are also allowing more roughness to persist – only 19 flags have been thrown so far, vs an expected 22 thrown based on the last 3 seasons.
Other – Because refs aren’t as familiar w/ the rulebook, they are not calling the other types of penalties that the typical referees call. Only 91 flags for offenses “other” than traditional. In 2 weeks of action, based on the last 3 years, we should have seen roughly 102 flags thrown.
Variance in Penalties Called – Week 1 to Week 2
It would be great to start examining trends and habits of these new replacement referees. The problem is, they are so new and 2 weeks of data is an impossibly small data set to pull relevant meaning from. It would be one thing if the referees consistently called too many defensive pass interference and not enough offensive holding. But that hasn’t been the case when comparing week 1 to week 2.
– Fewer defensive pass interference penalties were enforced in week 2: 26 enforced week 1, almost half that (14) enforced week 2. But when you combine DPI with defensive holding and illegal contact, week 1 saw a total of 32 of these 3 penalties, and week 2 saw 30, so they increased the defensive holding and IC such that the rate of these penalties remained relatively consistent from week 1 to week 2.
– The referees were also calling more offensive holding last week: they enforced 47 offensive holding penalties vs. only 25 the prior week. The 3 year average for offensive holding was 27 per week. So in week, there was an 88% increase in offensive holding penalties enforced vs wk 1 and 74% over average.
– More personal foul and roughness penalties called in week 2: Teams had 23 total personal foul or unnecessary roughness penalties enforced against them in week 2, compared to just 11 last week. After watching the week 2 games, you could say that they were still throwing the same number of flags proportionate to the amount of contact, because it appeared there were a significant number of scuffles and fights between teams, pushing the limits of what they could get away with and testing the replacements.
So what does this mean for bettors?
Home teams have a tremendous edge. It’s not just in what IS called, but what is not called. For example, in last night’s Monday Night Football game, there was fumble by the Denver Broncos driving into Falcons territory. A huge pile of players jumped on the ball, and it was impossible for the officials to determine who had the ball. So they began to unpile the players. Protocol is the team who emerges with the ball is the team who gets possession. However, while bodies still covered the ball, an official declared “red ball”, signalling for the home team, Atlanta Falcons. They continued unpiling bodies, only to find the Broncos actually were the team with the ball at the bottom of the pile. Inexplicably, the referee announced “the ball was recovered by Atlanta”.
- penalties CALLED against the road team (which are tracked),
- penalties incorrectly NOT CALLED on the home team (not tracked), and
- other blown calls in favor of the home team, such as ball possession, ball spots, clock issues, etc,
the advantage home teams (and their rowdy crowds) have had on the officials has been remarkable, and clearly measurable.
It’s translated into a record number of HOME WINS thru 2 weeks
The NFL average from 2002 thru 2011 the first 2 weeks is that home teams, favored by -2.5 ppg on average, win 18 games and lose 14 games SU (56%), winning on avg by less than a FG per game. ATS, these teams are a dead even 153-156-10 (49.5%) over these 10 seasons.
So far, home teams have been favored by -2.5 ppg on average and are 23-9 SU (72%), winning by 6 ppg. In addition, home teams are 19-12 ATS, covering over 61% of the time.
From week 1 to week 2, the difference increased. Perhaps it was increasing crowd influenced pressure from the home team’s crowd, but home teams in week 2 went an unprecedented 14-2 SU, winning by 9 ppg, and went 11-4-1 ATS.
Since the NFL expanded to 32 teams, home teams have NEVER won 14 of 16 (88%) games in a week.
The NFL average home field advantage has long been considered ~ 3 ppg. It actually has become less important than it used to be historically. From 1989 thru 1999, home teams won 59% of the time. But from 2000 thru 2011, home teams won 57% of the time.
The prime conclusion to draw at this point is that with these replacement referees, and home teams winning 72% of the time, compared to a week 1 and 2 average of just about 56% of the time, home field advantage should be increased over 3 points. However, predicting a specific number by which home field should be increased is impossible to do with confidence at this time, simply because there is not enough data to draw meaning from. There have been statistically significant swings in types of calls and frequency of calls from week 1 to week 2 alone, and the longer that these referees call games, the more accustomed they will become with “NFL speed” and bias of calls and focus of the officials will become more evident.
However, from what I have heard, I am fairly certain that these replacement referees may be here long term. And I am confident that I’ll be on the forefront of studying trends and patterns and employing them into my algorithms as soon as it reasonably makes sense to do so to gain an edge in handicapping the NFL this season.
Never has it been more accurate than now that the road teams must beat not the other team, but the referees as well.