Key Numbers When Betting Against the Spread
Each sport has some key numbers that sportsbooks pay close attention to when setting and adjusting lines for games. Some numbers carry more significance, such as point spreads in football, since scoring is accumulated in multiples. Meanwhile, for the rest of the major sports, key numbers don't play as big of a role since scoring can occur via a single point, run, or goal. That said, there are still some key numbers to be aware of for each sport, and bettors should have an understanding of these key thresholds when they wager, along with some techniques to take advantage of them.
Key Numbers When Betting Against the Spread
NFL
The sport where key numbers play the biggest significance is football. With scoring typically produced via field goals (three points) and touchdowns plus the extra point (seven points), it should come as no surprise that the most common margin of victory in an NFL game is by three points (15.2% over the last three seasons 2015-2017) followed by seven points (9.1%). The next group of numbers that are the most common and play into line setting include six (8.1%), 14 (5.1%), and 10 (4.8%), once again keeping with multiple combinations of three and seven. As such, sportsbooks tiptoe around these key numbers when setting lines for NFL games and are reluctant to cross over these numbers when adjusting lines.
NBA
The margin of victory expectation in basketball is much flatter than we see in football, with outcomes between one to nine points all occurring between 4% to 8% of the time during the 2017-2018 season. The numbers two and seven are the most commonly accepted numbers that carry weight when setting lines. The theory behind the number two comes from the idea of a game that is expected to be close and come down to the last possession. The number seven represents a lead that has become a three-possession game, which is more likely to end without additional fouling in the closing minute to push the score above or below that threshold. While these are the most common numbers considered in basketball, others also seem to be potential tipping points, such as five. None of these numbers play a huge role in the sportsbooks’ willingness to move a line over these thresholds, but there are some numbers to be aware of when looking at basketball lines.
MLB
In baseball, point spreads are static at 1.5 runs, with odds fluctuating between the underdog and the favorite based on the anticipated outcome. While this is a "key number" in baseball, the more interesting numbers come in the game run total instead of the point spread. In baseball, where scoring is lower, and the margin of victory is often just one run, game run totals of significance are predictably odd numbers, primarily seven and nine and, to a slightly lesser extent, five. Even numbers are less common since games cannot end in a tie.
NHL
Hockey follows a similar pattern to baseball. Point spreads are static at 1.5 goals with fluctuating odds between the underdog and favorite. The game goal total is an interesting number with low-scoring games in hockey that are often decided by a single goal. Five is the number in hockey as it is the most common number of goals scored in an NHL game and is an odd number since hockey games cannot end in a tie. As such, all hockey totals revolve around that number. The difference between a goal total of 5 compared to 5 1/2 or 4 1/2 becomes significant and will result in vastly different odds on the over and under depending on where the total is set.
Betting Advice for Key Numbers
While sportsbooks pay special attention to these numbers, you should also when evaluating wagers in each sport. As bettors, we have some ways to use these numbers to our advantage.
Shop around for different lines at different sportsbooks
You should be doing this, in general, to get the best odds possible for the wager you are looking to make, but it can become increasingly more important when a line is around one of our key numbers. Getting that extra half point (hook) in our favor will often be the difference between winning or at least pushing instead of losing.
Lock in your spread early
Lines that are initially set around key numbers seem to have a way of gravitating toward landing directly on the key number closer to game time. So, if you find a line that favors your betting interest earlier in the day or week, then consider locking it in early before it moves and you lose that critical half-point
Middling
Take advantage of opportunities to bet both sides in a game due to favorable line movement or different lines at different sportsbooks that straddle a key number, such as taking a favorite in football at -2.5 points and then getting the underdog in the same game at +3.5 points, thus allowing for a three-point outcome to win both bets while any other outcome will only lose the vig.
Buying points
Buying points is the process of moving the line in half-point increments at the cost of a higher vig. In general, it is probably not a good practice to deploy on a regular basis. The time you would want to consider it is when a line is hovering around a key number, especially in football, but of course, the sportsbooks also know this and will either not allow you to buy points when a line is at a key number or will charge more to move from a key number. In the end, it is probably best to avoid buying points.
Teaser bets
A teaser bet consists of combining two or more wagers into one bet where you can shift the lines of the games in the direction of the teams you are wagering. You need to win all bets in the teaser to get the payout, and of course, sportsbooks don't give away these points for free, so your payouts decrease from a typical multi-team parlay. Teasers are best used in football when you can move a line to skip across multiple key numbers. For example, if a favorite you like is at -8.5 points, a six-point teaser can drop the line down to -2.5 points and get you below both the 7-point and 3-point key number thresholds. Or you can move a -3.5 favorite to a +3.5 underdog by using a seven-point teaser, allowing you to go from being on the wrong side of the 3-point number as a favorite to the right side of the 3-point number as an underdog.
In general, be sure you are aware of these key numbers for each sport when evaluating lines and placing wagers. You don't always have to be on the "right side" of the key numbers to be successful or profitable, but if you make the extra effort to shop around for the best line possible and get on the "right side" more often than not, it can help increase your edge.
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Brad Richter is a featured writer at BettingPros. For more from Brad, check out his archive.