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NFL Point Differential Betting System

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Updated September 06, 2013

NFL Point Differential Betting System

When it comes to NFL betting systems, the Point Differential System is one of the most time consuming, but also one of the most accurate when trying to gauge the relative offensive and defensive strength of a particular team.

The system incorporates the strength of the opposition the team has played, which makes it a bit more accurate than basing a team's performance against the league average or the league median.

If a team is averaging 24 points a game, that doesn't really tell us too much unless we have something to base that against. The most common base is the league average or league median. If the average NFL team scores 21.6 points per game, we can now rank our team scoring 24 points a game as a better-than-average offensive team.

The one problem with this, however, is that it fails to take the defensive strength of the team's opposition into consideration. If our team averaging 24 points per game has played against opponents who allow an average of 27 points per game, our ranking of them as a better-than-average offensive team will be misleading. Instead of being a good offensive squad, the team is actually scoring three points less than they should, based on the opposition they have played.

That's where the NFL Point Differential System comes into play.

Doing the System Calculations

As I've mentioned several times in the forum, this system is probably the most time-consuming football system I use, and you'll soon see why.

Here are the steps required by the system to calculate the odds on a particular game. We'll list the steps and then go back and give some examples:

  • The first step of the system is to list all of the opponents the road team has played and the number of average points scored and allowed per game by each team.
  • The second step is to add the opposition's average points for and points allowed and divide by the number of games played. This step will give an average number of points scored and an average number of points allowed by the road team's opposition.
  • The third step is to divide the road team's points scored by the average points allowed by the road team's opposition.
  • The fourth step is to divide the road team's points allowed by the average points scored by the road team's opposition.

    Let's use the Atlanta Falcons at the Detroit Lions as an example. Through six games, the Falcons have scored 104 points and allowed 148 points, which translates to 17.33 points for and 24.67 points allowed per game. The first step of the system calls for us to list all of the Falcons' opponents and their per-game averages, so we would have something similar to:
    Minnesota 22.33-20.5
    Houston 18.5-20.33
    New Orleans 23-17.83
    Tampa Bay 18.83-17
    Dallas 26-18.16
    Oakland 16.33-19.17

    The second step calls for us to add up all of the totals and divide by the number of games played, which in this case is six. So, adding up all of the points scored by the opposition gives us 125.17 points (22.33+18.5+23+18.83+26+16.33=125.17). Diving 125.17 by six gives us 20.86, which is the average points scored by the teams the Falcons have played this season.

    The second step also calls for us to do the same thing for the points allowed by Atlanta's opposition. Adding the totals up gives a sum of 110.83 points (20.5+20.33+17.83+17+18.16+19.17=110.83). Dividing by six gives a total of 18.47, which is the average number of points Atlanta's opposition has allowed during the season.

    The third step is to divide Atlanta's average points scored (17.33) by the average number of points allowed by opponents, which is 18.47. Dividing 17.33 by 18.47 gives us a figure of .94. What this means, essentially, is that Atlanta is performing at 94-percent of an average offense, based on the opposition they have faced.

    The fourth step calls for dividing the number of points the Falcons have allowed by the number of points the opposition has scored. In this case, divide 24.67 by 20.86 and you get a total of 1.18. In this case, Atlanta's defense is performing 18-percent worse than an average defense, based on the opposition they have faced. A total of 1.00 would be average, while a total under 1.00 would indicate the team is allowing fewer points than an average team. Therefore, a defensive total above 1.00 indicates the team allows more than the average number of points.

    We will now do the same process for the home team, the Detroit Lions, who have scored 22.33 points per game and allowed 19.50 points per game for the purpose of our example.

    The fifth step of the system calls for us to list all of the Lions' opponents, so we would have something similar to:
    Green Bay 22.67-18.67
    Minnesota 22.33-20.5
    Chicago 20.5-22.17
    Tampa Bay 18.83-17
    Washington 16.5-13.67
    Buffalo 22.17-17.33

    The sixth step calls for us to add up all of the totals and divide by the number of games played, which in this case is six. So, adding up all of the average points scored by the opposition gives us 123 points (22.67+22.33+20.5+18.83+16.5+22.17=123). Diving 123 by six gives us 20.5, which is the average points scored by the teams the Lions have played this season.

    The sixth step also calls for us to do the same thing for the points allowed by Detroit's opposition. Adding the totals up gives a sum of 109.34 points (18.67+20.5+22.17+17+13.67+17.33=109.34). Dividing by six gives a total of 18.22, which is the average number of points Detroit's opposition has allowed during the season.

    The seventh step is to divide Detroit's average points scored (22.33) by the average number of points allowed by opponents, which is 18.22. Dividing 22.33 by 18.22 gives us a figure of 1.23. What this means is that Detroit is performing at 123-percent of an average offense, based on the opposition they have faced.

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