Sporting Charts

Vegas 'Las' Leader – Past Performance of Double-digit NFL Point Spread Favorites


Loss leader (noun) ~ A business strategy in which a product or service is offered at a price that is not profitable for the sake of offering another at a greater profit.

It is Friday night and dusk is about to fall on the San Bernadino Valley. Its origin spreads wide, but the masses begin to converge nearby on the I-10 heading east out of L.A. The night descends as they merge onto the I-15 and ascend trough the Cajon Pass. Its effect begins to take shape. They quickly move through the cool Barstow night air and align hypnotized as the Interstate rolls along the Mojave Desert. Looking south from Las Vegas, each vehicle approaches with the same luminous blank stare as their operator.

LAS VEGAS

The odds were not in her favor, but the lady over at the slots just cashed out with something extra. The guy sitting nervously at the table is about to walk away with four times what he sat down with. Individually, there are winners, but, in aggregate, the house always wins.

The statisticians have figured it all out. Craps has better odds than blackjack. Blackjack has better odds than baccarat. And they all have better odds than roulette. But, what odds do you get at the sportsbook? Are there certain matchups that have had better outcomes historically? Surely, the sportsbooks wouldn’t offer you an opportunity much better than 50/50.

LOSS LEADERS

Loss leader business strategies have long been associated with razor blades and electronics. However, The Strip’s pioneers would contend that its practice is the most prevalent in Vegas. There are the free drinks, the premium buffets for only a few bucks and, if you are fortunate, the comped rooms. But, how about betting on the NFL?

All those speeding down the I-15 see the flashing lights in their mind even if The Strip’s glow hasn’t yet appeared over the horizon. The twinkling casinos and mesmerizing slot machines act as beacons. The premier NFL teams act as the sportsbook’s beacon. Sunday morning is like a crowded mall in a bad zombie flick. Only, the undead are sporting Ben Roethlisberger and Brett Favre jerseys. They assemble to make bets on the Patriots, 49ers and Steelers. Even the unacquainted will scan the sports page before landing on front runners like the upstart Houston Texans.

The sportsbooks know loyalty, tradition and media coverage will outweigh logic in the minds of the masses. They know that large double-digit spreads validate a team’s stature in the people’s eyes. You are lured into believing the hype with each incremental uptick in the spread. How could you refuse to take the favorite? There is no way that the sportsbook would actually give you better odds to take the underdog. They are too wise to provide you with an advantage. Or, will they know you will ignore reason, past performance and odds and follow the flashing lights instead.

NFL - WEEK 10

The beacon was attracting considerable attention approaching Week 10. Until that point in the season, there had only been 12 double-digit spreads all season and at most two in a single week. The Patriots, 49ers and Steelers have combined for 14 Super Bowl championships. This accounts for 30% of all the Super Bowls played. For this one week, these three legendary franchises were heavy favorites and the sportsbooks were willing to bet that we would all support the front runners.

PAST PERFORMANCE

I have reviewed regular season data on NFL spreads from 1978 through the end of Week 11 of the 2012 season. The table below summarizes the percentage of instances in which the favorite covered the spread.

I have included separate results from 2002 when the Texans joined the NFL and the current divisional alignment was developed. I have also included results from 2008 to determine if the results have changed over the past five seasons.

 

1978 through
Week 11 of 2011

2002 through
Week 11 of 2012

2008 through
Week 11 of 2012

All games

46.8%

47.6%

46.6%

Games with single-digit spreads

47.3%

48.4%

47.6%

Games with double-digit spreads

43.7%

42.0%

41.0%


For example, between 1978 and the end of Week 11 of the 2012 season, 46.8% of favorites covered the spread. The occurrence of favorites covering decreased by 3.1% once I isolated the sample to only regular season games in which the spread was ten points or higher. The results show that there has historically been more of an advantage betting on the underdog in a matchup with a double-digit spread than when the spread was under ten.

The results from the beginning of the 2002 season indicate that the likelihood of heavy favorites covering the spread has decreased as the league has expanded and parity has become commonplace. There have been 173 regular season games with double-digit spreads since the beginning of the 2008 season. This sample size is significant enough to conclusively demonstrate that the trend is continuing to skew towards the underdogs.

I also analyzed whether the results would be affected if the opponents were divisional rivals. The percentage of favorites covering the spread dropped from 47.3% to 46.8% (decrease of 0.5%) in divisional regular season games with a single-digit spread. Moreover, the percentage dropped from 43.7% to 42.1% (decrease of 1.6%) in divisional regular season games with a double-digit spread. A decrease of slightly more than three times that of single-digit divisional match-ups.

My analysis was only an assessment based on past events; however, the results from Week 10’s most lopsided matches are now, perhaps, less shocking.

  • New England Patriots 37 - 31 Buffalo Bills
  • San Francisco 49ers 24 - 24 St. Louis Rams
  • Pittsburgh Steelers 16 - 13 Kansas City Chiefs


NFL - WEEK 11

Jacksonville Jaguars at Houston Texans (-15.5)

Only 2.7% of regular season games since 1978 have had spreads of two touchdowns or more. We had the second of the 2012 season during Week 11. Both games this year featured Super Bowl contenders pitted against the Jacksonville Jaguars. In late October, the Packers had a fright as they squeaked out a victory over Jacksonville. In Week 11, it was the Texans facing the Jaguars – a divisional rival. Similar to the Week 8 game at Lambeau, the Jaguars gave the heavy favorites all they could handle. The offensive showdown was tied after regulation and the Texans survived with a 43-37 overtime victory.

Analyzing the regular season data further, the decrease in the percentage of favorites covering double-digit spreads since 1978 is inversely proportional to the size of the spread. The table below summarizes my findings using regular season data from 1978 through Week 11 of the 2012 season.

Games with double-digit spreads (10+)

Games with at least two touchdown spreads (14+)

Games with at least 17-point spreads (17+)

43.7%

41.9%

32.6%


As you can see, the probability of favorites covering the spread based on past performance decreases further as the spread reaches at least two touchdowns and drops dramatically with spreads of 17 points or more. Since 2002, there have only been 11 games with spreads of at least 17 points. Since that time, only the 2011 New England Patriots covered such a spread in their 34-3 lambasting of the Kansas City Chiefs at Gillette Stadium.

IN AGGREGATE, THE HOUSE ALWAYS WINS

Sorry to disappoint you. I haven’t provided you with the goose that lays the golden egg. I can’t predict the future with any certainty. Not even a little bit. However, I can hope to point out interesting patterns in past results. And, these results do peak my curiosity.

If it isn’t society’s eagerness to jump on bandwagons and communally follow front runners, than what else could be the explanation for the sportsbooks continuing to over-credit heavy favorites despite the conclusive data at their disposal?

They wouldn’t possibly want you to win every once in a while. Would they? You would probably take your winnings and buy yourself a new Tom Brady jersey to wear on Sunday mornings. Next thing you know, it’s Friday again. Dusk is about to fall on the San Bernadino Valley and you are back on the I-10 heading east out of L.A.

Bob Sullivan writes periodically for SportingCharts.com and can be followed on Twitter at @mrbobsullivan.

NOTES:

The data on NFL regular season spreads was accessed via Sunshine Forecast whose current source is scoresandodds.com. Spreads are collected by Sunshine Forecast as close as practicable to game time.


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