Winning Percentage Differential Part 1

Betting Systems

NBA Betting System: Winning Percentage Differential System

By Ray Monohan

In basketball, betting systems are a bit trick since home court advantage plays such a huge role. Most of the teams in the NBA will finish with a winning record at home but very few will have a road record above .500. That being the case, most NBA betting systems I’ve seen tend to deal with that home-away advantage-disadvantage, but this specific system relies on a formula that seems to work quite well.

The System: This system has a little bit of an intricate process to it but it’s easy to grasp. Start by take the winning percentage of the two teams squaring off and subtract the small one from the big one.

For example, if the Chicago Bulls have a winning percentage of .800 and Toronto Raptors are at .300, then the difference is .500.

Next, you want to divide that differential by 20, which gives us our projected spread for the game. In this case, the spread would be 25. Give or take three points for home-court advantage, so Chicago would be -28 at home or -22 on the road. Then, subtract our projected spread from the real spread, and if the difference is 10 or more, you’ve got a play on the Bulls.

So if the Bulls are at home and the actual spread is -12, then the differential with our projected spread is greater than 10 (-28), so the Bulls are a play.

Here’s the formula:

(bigger winning percentage – smaller winning percentage) / 20 = projected spread

If projected spread > actual spread + 10, then you have a play on the favored team.

The last key to this strategy is to wait until we’re about a quarter of the way through the season. In the NBA, a lot of wacky things can happy early on but they usually straighten out by the end of the calendar year. So let about 30 games so that we can get a good gauge of the winning percentages before putting this system into effect.

The Logic: The logic to this system is quite understandable. Basically what we’re doing here is relying on a historic formula that shows us by the winning percentage differential that there is a huge discrepancy between the teams. When that disparity is reflected in the betting line, then we stay away. When the spread doesn’t respect how good the favorite is or how weak the underdog, then we bet the favorite.

Overall, this system is definitely successful and logical, but just keep in mind that there are sometimes other factors that come into play, such as fatigue (back-to-backs), injuries and coaching changes.

The Track Record: Rough estimates on this formula come in at about 60%.