A move on the point spread from the opening number to something different will shift the point spread winner 7% of the time. That is, if the Green Bay Packers opened as a 2½ point favorite over the Pittsburgh Steelers and the closing line had them favored by 5½ points, that shift would come into play 7% of the time.
How can we use that fact to our advantage?
When I first uncovered that number thirty-five years ago my assumption was that chasing a line was automatically a bad play because I knew statistically I was surrendering 7% winners. In fact, it often did point to a bad play not only for the shift, but the pick itself which was most often heavily backed by public action.
In more recent years, what once pointed to a bad play more often indicates a good play even while surrendering the 7% factor.
Because today’s point spread shifts are much more tied to “smart” money than public action. The books are forced to move lines not based on the number of wagers on a game but rather the amount of money on one side or the other. The wise guy plays generate a lot more dollar volume in comparison to public wagers in recent years. This can be evidenced in the line shift in home team underdogs.
If you bet all the home underdogs during the 1970’s and 1980’s you would have had only two losing seasons in 20 years and twice won more than 60% of your wagers with 63% in 1981 and 68% in 1978. Those winning point spread records were gained while only 34% of the home dogs were winning games straight-up.
Over the past ten years, 36% of the home underdogs have won the games straight-up, so one might assume their point spread record would be better than during the time only 34% were out-right winners. But, in fact, even though more home dogs won games their point spread record for the last decade has been reduced to 50% with 439 winners, 439 losers and 29 pushes.
Because the books saw the advantage they were giving with point spreads too high on home underdogs and wise guy money came in to capitalize on those spreads. While the public is still backing road favorites, the smart money forced the books to adjust the point spreads down on home underdogs. Teams that once got 3½ points at home are now only getting 2½ points and that is enough to weed out the inherent advantage in home underdogs across the board.
So, where does the advantage now exist on line shifts?
Even with the 7% reduction in wins from the opening number to the final closing line if the backed teams were smart plays to begin with, contests that beat the point spread at a 65% clip or better, then the shift would still reliably produced 58% winners.
Case in point.
Tonight, the Packers host the Steelers and the line on this game opened with home standing Green Bay favored by 2½ points. The Packers were determined by my numbers to be a good play even when the line rose to 3 points, but then on Tuesday of this week Steelers quarterback Ben Roethlisberger took a blow in practice that forced him into the concussion protocol. Now, he certainly is not going to see action in Green Bay while the Packers are starting Aaron Rodgers for his initial preseason work.
As soon as Roethlisberger was declared out of this game the wise guys headed to the books to get down on the Packers minus three points, and the public was soon to follow with the injury information. That forced the books to move the line up on this game to Green Bay by 5½ points.
In other words, the Packers are now forced to lay three more points on the line from the opening number and most of that shift is based on Roethlisberger’s injury.
A three point shift from 2½ to 5½ skips over two prime football numbers, 3 and 4, and all because a quarterback, that probably wasn’t going to see more than a series or two of action, is out of the game. In the regular season, where Roethlisberger would be counted on for 60 minutes his absence could justify a three point shift. But, in the preseason, it is too much of a shift to bet into a prime candidate for a game that could get caught by the 7% rule.
Wagers have to be made based on the spread on game day, and while we liked the Packers early in the week, we don’t get a line that justifies a wager today.