Originally Posted by
toddorts
You guys are making this way too complicated. The books follow a two step process:
1. Calculate a true line using all of the information that they have available to them, which is usually a lot more information than we have. Let's say they calculate the true line for the Heat at -16.
2. They analyze what the public's likely reaction would be to a line. If they post the true line, how will the betting public react to it? How will the "average" better see the line? They might figure that -16 would get too much action on the Cavs, because the spread is just so big that the average bettor will think the team getting points will hit. So, even though they think the Heat is likely to win by 16, it isn't likely enough to happen to justify the flood of money coming in on the Cavs. Over the long haul, the book would lose money, because the Cavs will win just enough to make it -EV. So, the book adjusts the line to where they think public perception will get the rake a little more even as a cushion in case the Cavs pull it off. A line of -13 will encourage more wagers on the Heat, while still getting more money on the Cavs, which is who the book thinks won't be able to cover.
It's really not that complicated. It's a two-step system of analyzing both the game and the public. Over time, they make much more money doing this than they would by just trying to get even money on both sides of all bets. No bookie is ever going to get rich taking nothing more than the vig. Sure, that's good revenue, but the real money is in expert analysis of both the game and the betting public.