If you have been keen on betting odds and point spreads when doing your research for an upcoming game, you will have noted that the odds keep shifting. This is referred to as line movement, and it’s effected by sportsbooks as a strategic plan to ensure that they remain profitable. However, if you understand it well, line movement opens an opportunity for bettors to get much more value for their bets and, in some cases, even win two bets with contrasting wagers (middling).
So what is line movement, and why is it so important for both bettors and sportsbooks? We’ll let you know everything you need to know in this guide.
What is Line Movement?
Line movement is simply the fluctuation of betting lines, specifically odds and point spreads, in response to various factors influencing the betting market. These movements occur from when a sportsbook releases odds to when the game starts and are usually gradual.
Let’s take an example of a basketball game between the Virginia Cavaliers and the Duke Blue Devils in the Virginia sports betting market. Initially, the sportsbook may set the point spread for the game at Virginia -5.5, indicating that Virginia is favored to win by 5.5 points. However, if a lot of money pours in on Duke, the sportsbook may adjust the point spread to Virginia -4.5 to try and attract bets on Virginia.
Factors that Cause Line Movement
Line movement is usually a response by the sportsbook to various factors, and understanding them will help you make more informed decisions.
Betting Activity
The most obvious reason why sportsbooks move odds is to react based on how most people are betting. If people bet overwhelmingly on a particular outcome, it means that the sportsbook is heavily exposed and can make losses if public sentiment proves right. To reduce this risk, the sportsbook will make the popular bet unattractive by reducing the odds and making the opposite more attractive. The goal is usually to have the total amount of money on both sides close to 50%.
Note that sportsbooks don’t gamble; they make a profit from what is known as “vig” or “juice.” For example, let’s say the sportsbook draws $110,000 in bets on Virginia at -5.5 (-110) and an equal $110,000 on Duke in the same game at +5.5 (-110). If Virginia covers, the bookie will pay out $100,000 in winnings but keep the $110,000 bet on Duke. That $10,000 difference is the vig. However, if significantly more money is placed on one side, the sportsbook may be exposed to a big loss.
Public Perception vs. Sharp Action
Besides the actual amount of money placed on different sides of a bet, sportsbooks also consider the type of bettors placing the bets. There’s the casual bettor who tends to go with the favorite and is heavily influenced by media narratives, popular teams, and recent performance trends. There are then professional bettors who tend to place much bigger bets and have access to sophisticated analysis, insider information, and advanced betting strategies.
If a sportsbook is getting more bets on the favorite but the sharp bettors are heavily backing the underdog with significantly more money, this will cause the bookie to think that the sharp bettors know something the bookie doesn’t. And in this case, they will also adjust the line against the betting activity, resulting in what is known as reverse line movement.
Injuries and Player Availability
Injuries and player availability are more straightforward reasons for line movements. The odds that sportsbooks provide usually represent the probability of that outcome happening. However, injuries to key players usually affect the probability of an outcome, so sportsbooks move the line accordingly. For example, if the 76ers had a point spread of -9.5 against the Pistons and news broke out that Joel Embiid is out, the spread would quickly shift to something like -4.5.
How to take advantage of Line Movements
If you monitor how the lines for a particular game have been moving, you can identify patterns and trends that can give you valuable insights. Look for discrepancies between these lines and consider your assessment of the true probability, as the sportsbook may just be shifting odds to cover their own risk. Besides that, monitor the news and latest developments regarding a particular game, as this will allow you to react quickly and take advantage before lines move.
