One area of football betting that has seen a surge in popularity over the past few years is "halftime wagering" where a player can place a stake on the outcome of a "half" rather than a full game.
The first half lines are a simple enough prospect, often close to the full line on a game divided by two. There’s usually a slight penalty to the favorite (a —7 line might be —4Â½ for the half).
By and large you can predict the lines with some accuracy if knowing the full spread. Sportsbooks can set first half numbers well in advance of the game and suffer no more than the typical exposure in the event of a bad line. On the other hand, the second half lines are where the real adventure takes place for the linemakers, books and players who elect to jump in.
For these latter wagers, linemakers send over a hastily created second half line and the casinos book a flurry of bets in the few minutes before the game resumes. With so little time to assess everything there is substantial room for error, which is one reason halftime bets are finding an audience among sharp players.
Our research is based upon using the full line divided by two to reflect an approximation of a halftime line. The first test is how often a team with the lead in the first half gets the "cover" in the second half against the full line divided by two.
In general, teams faring well in the first half, especially favorites, are unlikely to cover a second half line of "half the full spread." In terms of the actual second half lines, an underdog that’s ahead will receive a line that is closer to the full value spread than half of it. Likewise a big favorite that’s far in the lead will not be facing half of the full spread again.
The numbers in the table can also be flipped around to learn the comparable percentage for the team that is behind. For instance an away underdog that’s behind in the first half will "cover" half the full line in the second half at a healthy 59 percent clip.
The value seems to be in going against favorites with a lead who are giving at least half the original spread in points in the second half. Underdogs with the lead can be solid plays if they are getting more than half the original spread in the second half line.
There are key numbers in the NFL for spreads (3’s and 7’s) that make it elaborate to give a hard and fast rule as to what the difference in an extra point translates into for a winning percentage. Rest assured that 1 or 2 extra points can usually boost your expected winning percentage significantly.
Favorites with a lead outscore opponents in the second half most of the time, but not to the degree that they will cover the second half spread. And, dogs with a lead seldom outplay the opposition in the second half. However, unless you are looking at second half "money-lines" the first table gives you a better sense of which teams to back against a second half spread.
Bottom line: sharp players often feel over/under halftime betting offer great opportunity.
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