That's sort of a common myth too... as SCfinfan said earlier it's all about the projected balance of money bet. If a linemaker is expecting $1,000 to be bet on a game he's setting the line at what he expects it will take to get $500 bet on each side. It's not about the ranking of the teams as much as it's about a gauge on what you expect the betting public to respond to the line. If you think bettors are adding 3 points than the line setter does the same. Again it really has nothing to do with what they think the final score will be. It's all about being able to get as close to a balanced ledger as possible. You want to be able to take the losing money bet, pay the winners and keep the 10% vig for yourself. If your ledger has too much money bet on oneside of the line you run the risk of not getting enough money from the losing bets to pay off a vast majority of the winning bets and then you have to pay the diffence from your own pocket. Of course you're not going to always get balance that's why you see the line gradually nudged one direction or another during the week to entice more action on the weak side of the bets. Over the course of 16 NFL games during the week if you can keep the balance in a healthy range on most of the games you should make enough money over the course of a week to pay the winners and still make a profit.
