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Last Updated Aug 30, 2021, 14:03 PM

Mythbusters - NFL Edition

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Examining Commonly Held Notions for NFL Gambling

More than any other sport, football is a game of widely held “truths” on how to successfully play the game: “defense wins championships,” “teams have to run the ball to have success,” “you have to come away with points on this drive,” and so on.  Oftentimes, these widely held truths are actually myths – either the game has changed over time or they were never true to begin with.

Likewise, there are several commonly held beliefs about winning situations for NFL gambling.  These angles are taken to be “true” in many occasions without anyone bothering to look at data to justify them.

This article sets out to change all that – to provide the data on these instances using the records of every NFL game from the past 29 years as captured the game data at and unlocked by the Sports Data Query Language (SDQL).

Looking at the true results in these situations, we can determine if these “truth” should be confirmed or if they are myths that can once and for all be busted.

Trends are verified using Sports Data Query Language (SDQL)

Gambling “Truth” 1:    Double-digit favorites can’t be trusted

Mythbuster Result:  Busted

There is a belief that 10 or more points is just too many to ever lay with an NFL team.  Unlike in college, this theory goes, NFL teams are too similar in quality to ever want to give that many points to a team.

Examining the data we have shows that this notion is completely false.  Since the beginning of the database in 1989, teams are 434-441-17 ATS as double-digit favorites.  That 49.6% is not meaningfully different than 50%, and is certainly no reason to jump on a double digit dog, or to shy away from a big favorite should other factors suggest they are a play on. 

One major potential counter argument to this is that due to increased NFL party that recent results should be given an higher priority in this situation. We looked at double-digit favorites in games since 2010.  The results actually run completely count this argument – double digit favorites are 115-92-3 ATS since 2010 and that 55.6% would have made for a profitable play on over that time. 

To thoroughly exhaust the possibilities of large favorites, we also queried the result using a couple of alternate big lines.  Favorites of 13 points or more have an ATS record of 169-181-6 ATS, for a 48.6% cover percentage.  Favorites of more than 14 points are 63-68-2 ATS for a 48.1% cover percentage.  At any reasonable line, there is no reason to be scared off by the favorite and this gambling myth is BUSTED.

Gambling “Truth” 2:   Teams fall victim to trap games between rivalry games.

Mythbuster Result:  Busted

Trap games are something that gamblers love to cite and to try to take advantage of.  The idea is that a team is “trapped” between two important games with a game deemed less critical or not deserving their full attention. 

One issue is that what exactly makes up these trap games is ill-defined.  There are several possibilities as to what can be considered a trap game and we are going to look at two of them with the next two truths. 

The most commonly cited trap game is when a team has a game sandwiched between rivalry games.  In the set up of four teams per division, pretty much every divisional game is considered a rivalry matchup. So we want to isolate when a team is playing a non-divisional game immediate before and after a divisional matchup. 

This is not a particularly rare situation so we have over 1,300 instances in the database.  The results are not what gamblers following this strategy would hope for.  In database history, teams are 643-655-35 ATS, covering 49.5% of the time.  The results have not budged one bit in recent season, as teams are 203-207-6 ATS in this situation since 2008. 

A slightly different version of this would be to isolate teams playing a non-conference game between divisional games.  Teams are 277-288-15 ATS in this spot, covering in 49.0% of games.

Any benefit to be gleaned from this “trap” situation is so marginal that it is not actionable in any way.  This is another myth BUSTED.

Gambling “Truth” 3:  Teams fall victim to trap games as big favorites.

Mythbuster Result:  Confirmed

This is another one of the many definitions of a trap game.  This “truth” looks at a team that could get caught being not all in on a game where they are heavy favorites.  The trap part of the equation comes because they are playing in games with much tighter lines the week before and the week after. 

There is not a defined line for big favorites or tight lines but for the sake of this, we are considering “big” favorites to mean more than a TD and the tighter lines to be games where the team was not favored by more than four points. 

The result in this case is quite exciting, and shows a spot where the narrative is actually spot on.  Teams have failed to live up to expectations in these games, going a mere 248-318-7 ATS.  That is a cover rate of just 43.8%, or a play against rate of 56.2%, with 573 results over the database history.  That is an actionable situation.

There is one catch to this and that is while the line from their previous game is defined, there is no way to definitively know a team’s line in their next game.  But knowing the opponent and location of their next game should allow for a fairly accurate estimation and for the opportunity to use this truth that has been CONFIRMED.

Gambling “Truth” 4:  Don’t lay points with a bad team

Mythbuster Result: Mainly Busted

The notion is simple – that it is ill advised to lay points with a bad team.  Either they are playing a fellow bad team and it makes since to take the points in matchups of two bad teams, or they are laying points against a good team for some unusual reason.

One note is that for situations like this we usually want to start the results a few weeks into the season.  That is because in a small sample size, such as a 0-1 or 1-2 record, we do not necessarily get a true representation of a bad team, and it would be less unusual to see a team with that type record as a favorite.

There are several ways to define this situation, so we’ll look at a couple of them. To start with, we have teams that are favored when they have won less than 40% of their games in Week five of the season and beyond.  These teams actually have a positive ATS record of 404-369-18, covering in 52.3% of games.  We can look at even worse teams, teams that have won less than 30% of their games in week five of the season and beyond.  The result is just the same, as these teams are 215-196-6 ATS, covering 52.3% of the time as well.

We can also ramp up the degree to which these teams are favored.  When bad teams are favored by more than three points in these spots, they are 185-179-7 ATS, for a 50.8% cover rate.  When that line is bumped up to at least six points, the result falls barely under .500 at 80-83-5 ATS (49.1%). Getting the line up over a TD is finally turning point, albeit a small sample size, at 29-41-3 ATS (41.4%). 

There are ways to tweak the line and winning percentage at the higher lines to find play against situations. However, the basic concept of this myth, to avoid or go against bad teams that are favored, is BUSTED.

Gambling “Truth” 5:   Grab the points with a good team

Mythbuster Result:  Busted

This concept is a natural extension of the previous concept.  But the results of these two concepts are actually completely independent of one another, so let us did into the results and find out if there really is value in good teams that are getting points.

And just as was the case with truth four, there are several ways of defining good teams. To begin, we look at teams that are underdogs when they have won more than 60% of their games in week five of the season and beyond.  These teams have gone the other way, with a negative ATS record of 508-546-29, covering in 48.2% of games.  So to further this, we will look at even better teams, teams that have won more than 70% of their games in week five of the season and beyond. The result is more or less the same, as these teams are 272-290-14 ATS, covering 48.4% of the time.

Let’s also bump up the amount by which these teams are favored.  When good teams are getting more than three points in these spots, they are 269-291-9 ATS, for a 48.0% cover rate.  When that line goes all the way up to at least six points, the result is still under .500 at 135-139-5 ATS (49.3%).  Getting the line up over a TD is still a loser at 61-73-1 ATS (45.5%). 

No matter how we shake out the lines and quality of teams for this “truth”, this one is BUSTED.

Gambling “Truth” 6:   A team that can control the ball will have more success

Mythbuster Result:  Confirmed/Busted*

We chose to highlight this truth because it is an example of something we have seen quite often – a football truth masquerading as a gambling truth.  What we are looking is a matchup of a team that have been strong at controlling the ball throughout the season against a team that has been bad at controlling the ball. 

This is a result that can be easily searched using the SDQL because of the ability of its averaging function, with averaging the time of possession in all of a teams’ games on the season.  We want to look at games where the two teams are in contrast, with one team controlling the ball an average of at least 32 minutes per game on the season and the other controlling the ball for no more than 28 minutes per game on the season.

The result shows that the team that generally controls the ball more does carry a substantial edge in these games.  They have won straight up in 62.2% of these contests (296-180-0), an impressive number without defining anything else about the teams or game situation.  That is what makes a team that can control the ball being more successful a football truth.

But of course, that is something far different than a gambling truth.  Linesmakers know the difference in quality between these two teams and factor it into the line.  The team with better time of possession is favored by an average of 4.5 points in these contests.  And that has been absolutely the perfect number.  The team with better time of possession has performed dead even with the worse of the two teams in these contests, with each side going 233-233-10 ATS.  There is absolutely no value to be had gambling wise with that.

This is a situation where a football truth was confirmed, but a gambling “truth” was BUSTED.

Gambling “Truth” 7: Big 'dogs play better in rivalry games

Mythbuster Result:  Partially Confirmed 

There is a commonly held notion that big dogs play better in rivalry games.  The theory is some combination of that the bad team is more motivated than normal to get up for the rivalry game and that they are able to play a tighter game against a team they are familiar with. 

We again define rivalry games as all divisional contests.  Let’s start with looking at teams that are more than touchdown dogs.  In games against non-divisional opponents, teams are 513-494-10 ATS, covering at a 50.9% clip.  When it is a divisional contest, these divisional dogs are 418-375-12 ATS, covering in 52.7% of games.

It is interesting and maybe more beneficial to look at even larger, double-digit dogs.  Non-divisional dogs of 10+ points are 232-244-6 ATS, covering 48.7% of those games. In divisional contests, the double-digit dogs have performed noticeably better, going 209-190-11 ATS (52.4%). 

While this not necessarily actionable information in and of itself, that large divisional dogs do perform slightly better than non-divisional dogs is worthwhile information.  For that reason, we grade this “myth” as PARTIALLY CONFIRMED.

Gambling “Truth” 8:   Home teams have an outsized edge in primetime games

Mythbuster Result: Busted

This is a common “truth” we hear from football fans and gambling enthusiasts alike.  In primetime games, the atmosphere and a large, vocal crowd is suppose to give the home team an extra edge compared to standard weekend afternoon games. 

For this fact-finding we are isolating games that are played in non-weekend contests as well as the Sunday Night game.  So this includes Thursday night, Sunday night, Monday night, Thanksgiving, and the occasional rouge weekday game.   

For starters, linesmakers do not seem to be adjusting for an extra home team bump in the primetime contests.  Home teams in all games are favored by an average of 2.6 points per game on average.  In primetime games, the home team is favored by a slightly lower average of 2.4 points per game.  Primetime games tend to feature teams slightly closer than normally in competition level, so this adjustment makes sense but certainly shows that Vegas is typically not making any large line adjustments with their numbers to account for primetime. 

The results are quite underwhelming as well.  In all games, the home team has covered 49.8% of the time in the last 29 years.  In primetime games, that number ticks up only slightly to a 50.3% cover rate (566-560-31 ATS).  And home teams actually win less often outright in primetime games, 58.1% vs. 57.0%.  In just the last 10 years, the primetime home teams have covered at just a slightly better clip compared to all home teams (51.1% vs. 49.0%), but have nearly identical outright winning percentages (57.4% vs. 57.5%). 

Being home in primetime games just does not have the impact that football fans and some gamblers believe it does. This myth is soundly BUSTED.

Gambling “Truth” 9:   Ride a team on a hot streak/Go against a hot streak

Mythbuster Result:  Busted/Plausible   

This is one of the more unique gambling concepts we are familiar with because people tell it both ways.  Some same that you have to keep riding a team on a hot streak while others say that you should be going against these teams because they are overvalued.  Are either of these ideas right or is the answer somewhere in the murky middle?

There are varying levels of streaks so let’s start with the basics and work from there.  Teams on at least four game winning streaks are 526-554-30 ATS (48.7%).  At five games or more winning streaks, the result is the same at 307-324-17 ATS (48.7%).  When the streak is up to 6+ games, teams are 187-203-9 ATS (47.9%) and at 7+ games it is 119-130-5 ATS (47.8%).  It is all the way up to 9+ games, where we see a definatinve way to go with this one, as teams are just 41-67-1 ATS, covering in only (38.0%).  Eventually you do want to go against a team on a winning streak, though it is only really long winning streaks before this comes into play.

There is another kind of hot streak that is more gambling specific – a streak of covering or “ATS streak.”  Teams that have covered in at least four straight games are 286-324-19 ATS (46.9%).  When the gambling hot streak has reached at least five games , teams are 125-131-5 ATS (48.8%) and the streak gets to 6+ games, teams are 51-58-2 ATS, covering in 46.8%.  So this leans toward playing against as well, though not at a demonstrative rate.

There is at least value in knowing it does not make sense to simply ride a team’s hot streak and that myth is completely BUSTED.  As for going against hot streak, that idea provides a bit more mixed results, and there are some situations where it makes sense.  We grade the play against option as PLAUSIBLE.

Gambling “Truth” 10:   Teams suffer a letdown game after an upset win

Mythbuster Result:  Confirmed   

The “letdown” game, much like the “trap” game is a time-honored gambling concept.  There are a few possibilities of what could be considered a letdown game – based on the previous margin, previous line or simply a movement of lines.  For this we are going to look at the version we consider most basic – teams’ performance after an upset win. 

Winning as an underdog is not all that rare of an occurrence, with over 2,200 active instances in the 29-year history of the database.  Teams coming off that surprising win are 1068-1110-57 ATS, covering at a 49.0% rate.  But as we said, simple upset wins are not that rare so let’s those lines to look at previous victories that are even more surprising. 

Teams that were dogs of more than three points in their upset win, are 574-611-28 ATS (48.4%) in these next games.   Dogs of at least six points in that previous win,  are 296-338-13 ATS, covering at a 46.7% rate.  When that were really big dogs of at least nine points and pulled off the upset, are 87-107-7 ATS (44.8%) next game.

With the trend line moving in the right direction, there is a truth to be found in this notion of the letdown game when the upset was surprising enough.  This “truth” is CONFIRMED.

Closing Thoughts

The main takeaway is that gambling on the NFL is not easy.  If most of the commonly held gambling notions were actually true, everyone would be a winner and the Vegas Sportsbooks would be quickly going out of business.  That is obviously not the case.  We did find a couple of potential winners among these commonly held beliefs. And now that you know many of the widely held beliefs about NFL gambling are false, question them the next time you see someone blindly cite one of these when making a selection.  

The good news is that are plenty of gambling truths out there – situations that have proven to be true winners over decades of gambling.  The catch is they are usually more nuisance than the situations that were examined in this article.  They are also far less known than these commonly cited notion – and the gambling public being uninformed is often a major part of the long-term success.  Be sure to check out my weekly selections on VegasInsider.com for the 2018-19 NFL season. 

Trends are verified using Sports Data Query Language (SDQL)


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