How To Calculate Power Ratings
by Website Staff
Many sports bettors use
basketball and football statistics to calculate power ratings
which gives them a convenient and useful ranking system. Power
ratings can also be used to create a mock pointspread. A difference between the point spread created by
the sports bettor and the odds offered by the sportsbook may
indicate value for the bettor.
Basic Power Rating
Margin of victory, points scored minus points scored against is
the most common calculation used to formulate power ratings.
Game 
Points Scored 
Points Against 
Margin (M) 
1 
17 
20 
3 
2 
21 
31 
10 
3 
14 
10 
4 
4 
24 
13 
11 
Basic Power Rating
= (M1 + M2 + M3 + M4) /Games Played + 100
=
(3 +
10 + 4 + 11) /4 + 100
= 100.5
Weighted Power Rating
It is logical to assume that a team's most recent results are
the best indicators of how they will perform in their next game.
To account for this tendency, it is necessary to give more
weight to recent games.
For each team multiply the margin of victory for every game by the numerical
order in whch it was played. The margin of victory for game one
is multiplied by 1, the margin of victory for game two is multiplied by 2 and so forth.
Therefore game four will have a weight of 4 which is twice as
much as game two and four times as much as game one. The
weighted margins for each team's games are added and
divided by the sum of the multipliers. After four games the
multiplier sum is ten; 1 + 2 +3 + 4 = 10.
Weighted Power Rating
= (M1*1 + M2*2 + M3*3 + M4*4) /Multiplier Sum + 100
=
(3*1 +
10*2 + 4*3 + 11*4) /10 + 100
= (3 + 20 + 12 + 44) /10 + 100
= 103.3
Combined Power Rating
Unfortunately, basic and weighted power ratings do not consider a team's
strength of schedule. A more accurate power rating can be
calculated by averaging either a team's basic or weighted power
rating
with the current power ratings of their
previous opponents.
Calculate Team 1's combined power
rating after playing four opponents.
Team 
Power Rating (PR) 
1 
103.3 
2 
107 
3 
102.5 
4 
97.8 
5 
99.1 
First average the basic or weighted power ratings of Team 1's opponents.
= (Team 2 PR + Team 3 PR + Team 4 PR + Team 5 PR) /4
=
(107.0 + 102.5 + 97.8 + 99.1) /4
= 101.6
Average this value with the corresponding power rating from Team 1.
Final Power Rating
=
(103.3 + 101.6) /2
= 102.5
Point Spread
Power ratings can be used to predict the outcome of a game.
Subtract the away team power rating from the home team power
rating and add 3.0 points
for home field advantage.
Team 
Power Rating (PR) 
Home 
102.5 
Away 
99.5 
Point Spread
= Home PR  Away PR + 3.0
=
102.5 – 99.5 + 3.0
= 6.0
The home team is favored to win the game by 6.0 points. A
negative result would indicate a
home underdog.
As the season progresses and data is collected the power
ratings will become more accurate, but It may be necessary to
rely on other handicapping techniques early in the schedule.
