Betting lines are the odds that sportsbooks assign to different sporting events. The lines can shift up and down as the public and sharp bettors make wagers. Betting lines can be influenced by everything from injuries to weather forecasts. When a line is moved, it typically means that bettors are putting more money on one side of the bet than another. It can also mean that the opposite is true and that a large number of bettors are placing money on the underdog team.
When betting lines are released, the sportsbooks will compare power ratings of the teams to try and determine what the line should be. This is based on the assumption that if all bettors make equal wagers, then the odds will balance out. Professional bettors are known to make large wagers and will quickly split the lines. This can cause the lines to move up or down, depending on whether the bets are placed on either side of the spread or over/under.
As the game approaches, the lines will continue to shift as bettors place their wagers and new information becomes available. This is called line movement and can be a major factor in making a profit. The key is to identify this line movement and find value at the sportsbooks that have adjusted the lines. For example, a sportsbook may make the LA Rams a one point favorite over Buffalo but the line will move away from this at FanDuel. This is an example of reverse line movement and can be a huge advantage to bettors if timed properly.