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 (BPR)
Margin of victory, points scored minus points scored against is
the most common calculation used to formulate power ratiings.
Game 
Points Scored 
Points Against 
Margin (M) 
1 
17 
20 
3 
2 
21 
31 
10 
3 
14 
10 
4 
4 
24 
13 
11 
BPR = (M1 +
M2 + M3 + M4) /No. of Games Played + 100
(3 +
10 + 4 + 11) /4 + 100
= 100.5
Weighted Power Rating (WPR)
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.
WPR = (M1*1 + M2*2 + M3*3 +
M4*4) /Multiplier Sum + 100
(3*1 +
10*2 + 4*3 + 11*4) /10 + 100
= 103.3
Final Power Rating (FPR)
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 BPR or WPR
with the current power ratings of their
previous opponents.
Calculate the final power rating for Team1 after playing Team2,
Team3, Team4 and Team5.
Team1 PR = 103.3
Team2 PR = 107.0
Team3 PR = 102.5
Team4 PR = 97.8
Team5 PR = 99.1
FPR = [Team1 PR + (Team2 PR +
Team3 PR + Team4 PR + Team5 PR) /No. of Opponents] /2
Add the basic or weighted power ratings of Team1 opponents and divide
the sum by the total number of opponents.
(107.0 + 102.5 + 97.8 + 99.1) /4 = 101.6
Average this number with the corresponding power rating from
Team1.
(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 PR from the Home Team PR, add 3.0 points
for home field advantage and multiply the result by (1). A negative point spread
indicates a Home Favorite and a positive point spread indicates a
Home Underdog.
Home Team PR = 102.5
Away Team PR = 99.5
Point Spread = (Home Team PR  Away Team PR + 3.0) *1
(102.5 – 99.5 + 3.0) *1
= 6.0
It is predicted that the home team will win the game by 6.0
points.
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.
