We do this based on a Linear Regression that includes:
-a player's contributions (Dean Olivers Offensive Rating and Usage%)
-his teammate's contributions (based on four estimates)
The four estimates of his teammates are as follows:
1) Total Offensive (ONcourt)= TeamORTG(ONcourt)-playerUsg%*playerORTG
2) Average Offensive (ONcourt)= (TeamORTG(ONcourt)-playerUsg%*playerORTG)/(1-usg%)
3) Total Offense (Season) = TeamORTG(season)-playerusg%*ORTG*min%
4) Average Offense (Season)=(TeamORTG(season)-playerusg%*ORTG*min%)/(1-usg%*min%)
We take these variables versus a player's On-Court Offensive Efficiency, to give us the following regression (which has an R^2 value of >.99 since the x values are based on splitting the y value up):
Source Value Intercept -5.674 USG% 33.516 ORtg 0.193 TMO-1 0.302 TMO-2 0.554 TMO-3 -0.009 TMO-4 0.011
Since Plus-Minus is the more inclusive stat, we will take that stat and adjust from there. We simply take the player's Offensive +/-, subtract the TMO variables (times the coefficients), then add the average TMO variables times the coefficients.
The results can be found here: http://dl.dropbox.com/u/241759/adjusted%20offense.pdf
The results can be found here: http://dl.dropbox.com/u/241759/adjusted%20offense.pdf
