Next, take this number and subtract the actual spread on the game. If the difference is 10 or more, then you play on the favorite. If the result is less than 10, lay off the game.
The following is an example of the above:
Miami’s winning percentage = .800
Orlando’s winning percentage = .400
Difference: 40 / 20 = 20
Miami is playing at home so your rough spread is 23 and Orlando is a nine-point road underdog. This difference is 10 or greater, so you have a play on the Heat.
NBA Christmas System Qualifiers
The favorite cannot be playing the second of back-to-back games.
The favorite cannot have an injured starter out of the lineup.
Exclude any games with a posted line of 10 points or more
When an underdog becomes a favorite
Occasionally, you might come across a situation where it makes sense to play the underdog using this system. Suppose Philadelphia has a winning percentage of .400 and it is playing Toronto, which has a winning percentage of .320. The difference would be 80 divided by 20 for a rough spread of four points.
If the 76ers are playing at home, the rough spread would be seven points. If Toronto happened to be a road underdog of eight or more points, you would have a play on the Raptors as they would now be favored using this system.
How to successfully use this system
As with any betting system, past results does not ensure that the same will hold true in the future. Reportedly, the NBA Christmas Betting System posted a 60 percent winning percentage in the past, which is not bad, but not good enough to wager your entire bankroll on it. It is always best to pick a few games where there would be a play and track the results. Also, always use the smell test on any game that you consider playing. If your confidence level remain low with a particular matchup, do not make a play on it just because it met the parameters of the system.
A good money management strategy would to keep your units low on the first five or so plays. If the system is working, then you will be able to build-up a bankroll for bigger plays down the road. If it has gone cold, then your overall risk will have been minimized.