Key numbers are the most common margins of victory in football and basketball, which also makes them the most desired point spreads by bettors wagering on games in those sports. Of course sportsbooks know that as well and charge a premium to buy points on either side of key numbers, especially in the NFL where they are much more apparent due to common results often occurring because of the league’s scoring system.
Key Numbers in Football
In football, the most obvious key number is 3 points. Games that are tied late (or eventually go into overtime) are most often settled with a game-winning field goal since teams tend to play much more conservatively and go for the 3 instead of the 6 for a touchdown as soon as they get within scoring range. Research has found that NFL games end by a 3-point margin about 15% of the time.
The NFL’s other most common key number is 7 points, coincidentally happening 7% of the time. This makes a lot of sense as well, considering touchdowns with extra points are worth seven points. If teams are up by between four and seven points near the end of the game, their opponents will more than likely be going for a touchdown since a field goal will not help them even the score or earn a victory. If they fail to score that touchdown, the winning team can simply run out the clock and secure their 7-point win.
Sportsbooks are hesitant to move away from key numbers, none more than the extremely common 3-point spread. Instead, you will often see the price adjusted as an alternative point spread shaded to one side or the other. For example, if the Seattle Seahawks are -3 (-110) and receiving a lot more action as the favorites than the San Francisco 49ers as the underdogs at +3 (-110), sportsbooks may choose to move the prices on both sides to San Francisco -3 (-120) and Seattle +3 (+100).
Keep in mind, sportsbooks do not want to move off a key number like the 3-point spread altogether, because if they were to move Seattle from -3 to -3.5 and get a lot of action on San Francisco +3.5, a 3-point win by the Seahawks would result in a major loss. While action on Seattle -3 would result in a push, they would have to pay all bettors who had the 49ers at +3.5.
Key Numbers in Basketball
Key numbers in the NBA are a bit harder to analyze, but the most common one is 7 points, which happens a little more than 7% of the time. The reasoning behind this boils down to the act of fouling at the end of the game. When the scoring margin gets to seven points, it becomes a three-possession game, and the losing team will end up conceding most of the time. The 3-point shot will keep most good-shooting basketball teams in a game if they are within double digits. That is, until time runs out on them.