A fairly old NBA betting system has made a comeback, although with an addition, essentially making it a two-part system. The reported record was over 60-percent last season, so it appears to be working as well as ever.

When I first heard about the system it was called the Christmas System, as it wouldn’t take effect until after Christmas, giving every team the opportunity to play roughly 25 games or more. Currently, the system is being used after each team has played approximately 20 games, which will be around Dec. 12 this season.

The First System
The first system is fairly easy to use, although it may sound a bit complicated the first time you read it. It will soon become second nature, however, so don’t worry.

The first step is to take the winning percentage of each team, which is easily found online or in any newspaper, and subtract the lower winning percentage from the higher percentage.

For example, if the Celtics have a winning percentage of .750 and the Atlanta Hawks have a winning percentage of .450, the difference is .300. We will drop the decimals for ease of use with the system.

The second step is to dive the percentage differential by 20. In this case, we will divide 300 by 20 for a total of 15, which would mean our rough line on the game is Boston by 15 points.

Allow three points to the home team, so Boston would be -12 on the road or -18 if the Celtics are at home.

Subtract the point spread from the favored team and if the difference is 10 or greater, you would have a play. So, if the Celtics were favored by 2.0 points or less, or were the underdog on the road, they would be a play, as 12 – 2 = 10. If the Celtics were at home, they could be favored by as much as 8 points to be a play, as 18 – 8 = 10.

If the Celtics were favored by three or more on the road, or nine or more at home, there would be no play, as the difference is less than 10 points.

There are several qualifiers, such as the team cannot be in the second of back-to-back games, cannot have an injured starter, and no games with a point spread of 10 or more points is considered.