Sharp Sports Betting is a tool for those interested in winning money at sports betting. The book explains the most common sports bets, what all the numbers mean, and the mathematics behind the numbers.

A term frequently used by sports bettors is home-field advantage. The home team in the NFL has an advantage that averages three points per game.

Linesmakers know about the three-point home-field advantage in the NFL. They build it into the lines. So knowing that the home team has an average of three points of natural advantage will not help you to win money betting on NFL games.

The average might be three points, but the home-field advantage seems to vary from game to game. If you can do a better job of estimating the home-field advantage in particular games than is built into the lines, you can get an edge over the sportsbooks, whether they be land-based or online.

## Points Scored

By looking at games played in recent seasons, you can see that the home field has a significant impact on American football games. You can use scores of past games to estimate the home-field advantage.

Since there is no bias in scheduling regular-season games that results in playing more games at the homes of better teams, home teams overall are not stronger than visiting teams. Yet year after year, in the NFL regular season, home teams score hundreds more points than visiting teams. It’s a certainty that next season, home teams will once again score hundreds of points more than visiting teams.

The average home-field advantage in the NFL has hovered around three points per game. Some years it has been more than three points and some years less, but three points seems like a reasonable estimate of what next year’s home-field advantage is going to be.

For games played in neutral sites, such as those Super Bowls in which both competitors are from out of town and the home team is not involved, neither team has a home-field advantage. One visiting team might be assigned the home team’s locker room and have its score appear on the home-team side of the scoreboard, but that does not give it a home-field advantage.

## Games Won

Whatever the reason for it, the home-field advantage is clear from studying the results of past games. Home NFL teams have won dozens more games per year than have visiting teams.

In NFL playoffs, the home teams have won over 70 percent of games straight up. But in playoff games, the team with the better record is rewarded by having the game played at its home field. Thus you would expect home teams to win more than half of playoff games even if there were no such a thing as a home-field advantage.

Year after year, home teams win more games than visiting teams. Being the home team makes quite a difference.

## Three Points

To get another estimate for the magnitude of the NFL home field advantage, I used Excel to award points to each visiting team for each NFL regular-season game. I wanted to see how many points I would have to add to bring visiting-team victories in line with home-team victories.

The answer is three points. Adding three points to the score of each visiting team of each NFL regular-season game played since 1990 eliminates the disparity between home and visiting NFL teams. Giving each visiting team 2.5 points teams -- and giving each visiting team 3.5 points swings the pendulum too far, giving too many victories to visiting teams.

## Getting an Edge

The average NFL home-field advantage is three points, but that does not mean that the home field favors the home team by three points in every single game. There might be games for which the home-field advantage is more than three points, balanced out by games in which the home-field advantage is less than three points.

If, for example, the home-field advantage is two points on half the games and four points on the other half of the games, the overall home-field advantage still would average three points.

You might be able to find an occasional good bet by developing an understanding of how the home-field advantage works. This is one of the areas in which I personally am always looking for good bets.

I do not claim to understand how home-field advantage works. Even if I understood it, I would not explain it in writing, because it would be read by linesmakers and what I write might be reflected in lines of future games.

One important factor in estimating the strength of the home-field seems to be the importance of the game. The more important the game is to the home team’s players, the larger the home-field advantage.

## Conclusion

I think the home-field advantage is an area still ripe for finding good bets. My advice if you look for an edge in this area is to keep in mind that the average home-field advantage in the NFL has been three points over the years, and likely will stay around three points in the future. If you can find a category of team for which the home-field advantage is less than three points, then there must be a counterbalancing category of team for which the home-field advantage is more than three points.

I can give you a hint to narrow your search for factors that help explain home-field advantage: I live near the ocean, and high tides do not water my lawn.

This is part of an occasional series of articles.

Excerpted with permission from Sharp Sports Betting by Stanford Wong, edited for this format.