Player Evaluation Metrics
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|There are 5 entries in the glossary.|
|Scoring Player Possessions|
Author: Dean Oliver
A player's scoring possessions would be his field goals that weren't assisted on, plus a certain percentage of his field goals that were assisted on, plus a certain percentage of his assists, plus his free throws made.
Scoring Possessions Formula=(Field Goals Made) - 0.37*(Field Goals Made)*Q/R + 0.37*(Player Assists) + 0.5*(Free Throws Made)
Q=5*(Player Minutes)*(Team Assist Total)/(Team Total Minutes)-(Player Assists)
Author: Dean Oliver
The estimate of how many seasons the player has left to play.
Seasons Left Formula=27-0.75*(Age of The Player)
|Simple Projection System|
Author: Tom Tango
It's been developed to account for aging when calculating player efficiency. SPS uses 3 years of data, with the most recent data weighted heavier. It regresses towards the mean. So the model has an age factor and the numbers are adjusted to account for age.
An example of how the SPS is calculated for Dwight Howard's rebounding in 2008-09 season by using data of previous three seasons.
Author: Dan Rosenbaum
Statistical Plus/Minus (SPM) is an estimate of the player's contribution to the team's point differential per 100 possessions, using his box score stats as inputs. In another words, SPM can be considered as a way of estimating adjusted plus-minus from box score stats. Statistical plus minus puts a weight to basic box score stats like, points, steals, blocks etc., in a effort to solve the lowest mean residuals (average errors).
The goal with the SPM technique is adding a more stable component to player's basic stats as a counterbalance to the basic plus-minus. As a well known fact, basic plus-minus can be wildly inconsistent for individual players from season to season or under different coaches in a season.
Dan Rosenbaum has outlined different ways of addressing adjusted plus-minus' accuracy issues, by employing additional analyses based on box score stata.
In a lot of cases the statistical plus/minus ratings might be a more accurate predictor of future defensive performance. To characterize past defensive performance, adjusted plus-minus does a good job. A combination of the adjusted and statistical plus-minus will do a better job when we want to find out which players are going to be good or bad defenders in the future.
Comments: Statistical Plus/Minus is an "organic" way of deriving a linear-weights-style box score based formula from actual, real-life data.
Steal Percentage is the percentage of estimated opponent possessions that end with a steal by the player while the player is on the court.
Steal Percentage=100*(Steals*(Team Minuted Played/5))/(Minuted Played*Opponent's Possessions)