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How Do Betting Lines Work?

How Do Betting Lines Work? article feature image

Randy Sartin-USA TODAY Sports. Pictured: Tennessee Volunteers forward Grant Williams (2), Mississippi State Bulldogs guard Lamar Peters (2).

  • Every sportsbook has a head oddsmaker who sets the line on a given game, matchup or event.
  • Oddsmakers lean on computer algorithms, power rankings, win totals, futures and consultants to determine the odds.
  • Oddsmakers tweak the line based on adjustments, including injuries, weather, home-field advantage and head-to-head matchups.

In order to place a wager, bettors need to have access to a sportsbook or casino. These are the places, both physical in person and online via your smart phone, that take in bets and pay out money.

There are many different sportsbooks and they feature a countless number of employees, ranging from cashiers, technicians, betting analysts, accountants, security guards, surveillance officers and hospitality staff.

But the most important person at a sportsbook is the head oddsmaker. This is the person who creates the odds on any given game or event that people can bet on, also known as “setting the line.”

The head (or lead) oddsmaker has unmatched betting knowledge. Oddsmakers are math experts with decades of experience who know betting like the back of their hand.

How does Vegas set the line? 

In order to come up with the odds on a given game or matchup, oddsmakers use a complex set of mathematical models, formulas and computer algorithms. They also come up with power rankings based on key statistical categories, including strength of schedule and margin of victory.

This allows oddsmakers to compare teams against one another and determine which team should be favored and by how much.

Oddsmakers also take into account win totals and futures odds when helping to determine the odds. Win totals are set for every team and are available to bet on all offseason. Because they take in so much action from professional players, the market is very sharp and tends to be incredibly accurate.

Futures odds change throughout the season based on how well or how poorly teams are performing. They provide an up-to-date snapshot on the strength (or lack thereof) of every team.

Oddsmakers also lean on a team of trusted consultants who give valued input on what they think the odds should be based on their vast experience in the industry.

After consulting their computer models and power rankings, oddsmakers will come up with a rough estimate of what the odds should be.

Then they adjust the line based on a number of important criteria. This includes home-field advantage (typically three points in the NFL), injuries, weather, unique scheduling/travel spots along with specific head-to-head matchups.

If a great passing offense is going against a depleted defensive secondary, that is factored into the odds. If a team playing on the second night of a back-to-back and didn’t get in until 3 a.m., that is also taken into account.

What happens after a line is set ?

Once the odds are finally set, they are released to the public in the form of the “opening line” or “opener.” Bettors can then pick which side they want to bet.

At first, the limits are low. This means that bettors can only wager a relatively small amount of money on the game. Oddsmakers use this early period as a “feeling out” stage. They will allow sharp bettors to bet the game at low amounts in order to shape the line and make it as accurate as possible. Once they feel comfortable with the number they’ve set, the limits are raised.

Then the market takes over. Oddsmakers will adjust the odds leading up to game time based on the action each team is attracting.

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