Explanation of Composite Score Player Rating System
By Jon Nichols
The Composite Score rating system consists of two components, Offensive Composite
Score (OCS) and Defensive Composite Score (DCS). Each is made up of a combination
of three advanced statistical metrics and then adjusted based on a player's
position and playing time. The rating system is always under construction, so
the system used today may not be as good as one you could see in a few weeks.
Kevin Garnett
First, let me explain OCS. It is a combination of three statistics:
the Offensive rating system developed by Dean Oliver (which can be found at
basketball-reference.com), PER production (found on the team pages at 82games.com),
and offensive plus-minus, found at basketballvalue.com. I then adjust
offensive rating and PER production for position. Next, I add up the three z-scores
for the three stats for each player and multiply them by 10. After adjusting
for playing time (whether or not most of it is against starters or benchwarmers),
Offensive Composite Score is complete.
Offensive ratings are an
incredible measure of efficiency. PER also measures efficiency but takes into
account players with higher usage rates. +/- is a great indicator of how well a
player is fitting into his team and helping them offensively.
The average score is set at 0.
- -40
and below: Terrible - -40 to
-20: Very bad - -20 to
0: Below average - 0 to
20: Above average - 20 to
40: Very good - 40+:
Elite
Player rank percentiles were also
included to get a relative value of each player.
Next is an explanation of
DCS. DCS uses the mirror statistics of
the three used for OCS. Instead of
Offensive rating, it uses a very similar Defensive rating. Instead of PER, it uses counterpart PER,
which is basically the PER accumulated by a player's defensive matchups. Finally, instead of offensive plus-minus,
I use defensive plus-minus. The
scores are on the same scale as OCS.
Composite Score (CS) is a
combination of OCS and DCS.
Counterpart PER, and PER were found
at 82games.com. PER, or Player Efficiency Rating, was developed by John
Hollinger. Offensive and defensive
ratings, which were developed by Dean Oliver, were obtained from basketball-reference.com.
Adjusted plus-minus can be found at basketballvalue.com. Player names and positions were obtained from
dougstats.com. I used an adjustment for starters based on the formula developed
at the APBRmetrics message board.
Glossary of terms on
stats pages:
OCS - Offensive Composite Score
OCS Rank - How a player ranks offensively among all the
players in the league that qualify (at least 500 minutes played)
DCS - Defensive Composite Score
DCS Rank - How a player ranks defensively among all the
players in the league that qualify
CS - Composite Score (OCS + DCS)
CS Rank - How a player ranks overall among all the players
in the league that qualify
Comments are greatly encouraged and can be sent to
jonn@hoopsdaily.com