For sportsbooks in Nevada and overseas, NFL halftimes can be the most hectic 15 minutes of the week. The first halves of many games are ending at the same time, especially for the early games, and bookmakers are faced with the task of setting second half lines for all the games on the board and then managing their odds due to the action coming in.

The professional bettors - referred to as 'wiseguys' in the industry - are looking to attack a weak number. Informed recreational bettors, who are making their wager after watching the first half of a particular game, are loading up on the second half. Others are

For sportsbooks in Nevada and overseas, NFL halftimes can be the most hectic 15 minutes of the week. The first halves of many games are ending at the same time, especially for the early games, and bookmakers are faced with the task of setting second half lines for all the games on the board and then managing their odds due to the action coming in.

The professional bettors - referred to as 'wiseguys' in the industry - are looking to attack a weak number. Informed recreational bettors, who are making their wager after watching the first half of a particular game, are loading up on the second half. Others are looking to hedge their bets or middle the book (attempting to win both sides of a bet by having the game number fall in the middle of two lines wagered on opposite sides) by going against their straight bet team in the second half.

In situations where many games are entering halftime concurrently, the books have only a couple of minutes to chose their position on a multitude of games. If they make the wrong choice on even one line, it can cost them big time.

"As quick as you put (a bad number up), you have 10 guys on the phone wanting to take it," said Doc from Rio, the head oddsmaker for Skybook. "Halftimes in the NFL are just as busy or busier than the actual 10 a.m. (PST) rush. When seven or eight games are going it's also more hectic because you have to be more on top of (the numbers). You really have to be paying attention."

"You have to be real sharp on your opening second half number," added Leo Shafto, head oddsmaker for Royal Sports. "You can't really afford to have a lot of movement on your second half number or you kind of defeat the purpose ofwhat you were hired to do, and that's to manage the risk. By movingthe number too much for the second half you create exposure forthe sports book. You learn pretty quick that (the professionals)are like vultures waiting on a branch. As soon as you have a flawin the number they are ready to pounce."

There are a few shops that post the initial secondhalf numbers then, once the wise guys have flattened them out,the rest of the industry usually goes off of those lines. Bookscan keep tabs on the numbers posted by their competition by monitoringthe Don Best odds service, which most of the bookies in the industrysubscribe to. This service allows books to track posted odds andline movements for Nevada and offshore books.

According to oddsmakers, a combination of severalcriteria is used to come up with second half lines. The originalline for the full game is always a consideration, as is the resultof the first half of the game. Bookies also set the number accordingto the betting patterns of their clientele. If they have unbalancedaction on for the full game, they may try and use the second halfto balance their action or even attempt to middle the majorityof their clients in a particular game.

The public prefers to bet the second half ratherthan the first half, said Shafto. In certain cases where bookiesknow that the public is going to go after a certain second-halfside, the number will most likely be shaded towards the favorite.

"A lot of times we book more second halfaction than first half action because I think the public likesto bet the second half more," he said. "They like to watch the game and see how (the first half) goes. A lot of timesthey are trying to hedge or try and (get the middle). Or if theirside is winning the first half, it might influence them to beta little more (on that side) in the second half."

The professional bettors tend to play first halvesmore because those numbers are available for most of the weekwhile second half numbers are available for only roughly 15 minutes.This gives the wise guys more time to shop around for numbersand get the best value for their wagers. Public bettors preferthe second half because they often believe they have an edge becauseof what they watched happen in the first 30 minutes of a game.

"(The public) is not so much influenced bythe math and the numbers as they are by the performance on thefield," commented Shafto. "I am not saying that's rightor wrong. But generally people take into account what happenedin the first half and maybe that is going to be very indicativeof what is going to happen in the second half. I don't necessarilybelieve that to always be true because the coaches are a littlebit smarter and they do make adjustments at halftime."

Since so many public bettors are betting secondhalves, there are obviously opportunities to get value by goingagainst them. Books tend to overvalue the favorite in the secondhalf just as they do the full game because they know that is wherethe public money will fall. Many public bettors will jump on abig favorite for the second half that is down heading into halftime.This is exactly what the bookmakers would like to see happen.

"(We) know the public is going to bet thatside," said Doc from Rio. "Usually the underdog thathas played well in the first half is probably going to continueto play well, especially in the NFL."

Jeremy Martin is a writer for www.docsports.com