2021 NFL Week 1: Niners and Rams Betting Spreads Make for Irresistible Teaser
The Play: Seven-point teaser (-140), San Francisco 49ers -0.5 & LA Rams -0.5
Teasers are wagers that entail picking two or more outcomes, but with some enhanced (teased) line that purportedly accounts for the added difficulty of capping multiple events. Many sportsbooks offer six, six-and-a-half and seven point teasers, but ten-point teasers also exist (though the latter is commonly associated with three or more picks, due to the really high juice).
In the table above, we review the calculus for the most common two-game teasers. Note that in order to breakeven wagering two-game, six-point teasers, a hypothetical bettor would need to cash in 54.5% of the time. Worth mentioning, juiced up odds require a higher level of accuracy to turn a profit versus the 52.4% cover rate needed to avoid losses at the standard-110 vigorish. Going further, each teased leg of the bet needs to win 73.9% of the time, on average, to justify the effort of handicapping events for teasers.
To maximize the potential of covering teaser bets, conventional wisdom holds that teased lines should cross through several important spread levels. For instance, per the following graphic, the most common outcome in the NFL between 2010 and 2018 was a home win by three. When the home team won, the second most most common margin was (not surprisingly) seven, and then six. A teased line that reduces the threshold for collecting from more than a TD and PAT, through seven six and three--among the most frequently recurring margins in the game, greatly increases the chance of the payday.
Against this backdrop, we recommend combining plays on the Chicago Bears at the Los Angeles Rams -7.5 and the San Francisco 49ers -7.5 at the Detroit Lions into a two-game, seven-point teaser (-140). As such, the Niners and Rams need only win to secure the cover (they both have to win though).
Using BetLabs' extensive database, we looked at regular season contests featuring spreads of 7-7.5. Favorites won 78% of 500 contests that met these criteria. In an effort to provide more conservative forecasts, we next eliminated divisional play, which boasted a slightly higher win rate. The straight up win rate fell ever so slightly, from 78% to 77.4%, as indicated in the graphic below.
Importantly, the 77.4% historical success rate for non-division favorites of 7 to 7.5 eclipses the 76.4% rate required to breakeven betting seven-point teasers, implying this system has turned a profit, but not a large one.
Of greater comfort to inclined bettors, such contests beat (seven-point) teased lines 90% of the time. This hit rate proved statistically significantly different than the 76.4% breakeven rate at greater than the 99% confidence level, and implies approximately a 39% return on investment.
More fundamentally, FiveThirtyEight's Elo-ratings based NFL forecasts as well as ESPN's Football Power Index give the Rams about a 4.5 point neutral field edge over the Bears Sunday. We find that over the long-term, home field advantage has been worth approximately 2.2 points for Los Angeles. Thus, fundamentally, LA looks about a touchdown better than Chicago in week 1, offering ample margin for our purposes.
These same frameworks make the Niners 7-8 points superior to the Lions in an unbiased stadium for the first action of the new season. On average though, home field has been worth 2.2 points to Detroit since 2003-04, so a spread as tight as 5ish might be in order for this game. Nonetheless, while the Niners may not appear poised to cover the listed line through this lens, the straight up win still appears quite likely.