Easy Player Rating System!

As a basketball statistician, I am thoroughly obsessed with Jeremias Engalmann's Adjusted Plus-Minus numbers.
As a basketball fan, I realize that most people are hesitant to even attempt to understand what's going on in Adjusted Plus-Minus.

To combine the two worlds, I have looked at the latest four individual seasons of data, and I have compared advanced basketball stats with the Adjusted Plus-Minus numbers. By using four advanced stats (easily found at Basketball-Reference.com: per game, per season, or per-career), we can estimate how much a player impacts their team, per possession.

Here are the four statistics:

-Minutes per Game
-Offensive Rating (ORTG)
-Usage% (Possessions used)
-Defensive Rating (DRTG)

I made a regression of values to predict the Adjusted Plus-Minus, and averaged each season from 2008-2011 (with players having 500 minutes or more). The result is the following:

=(0.035 x Minutes/Game) + (0.43 x (Usage%/100) x Offensive Rating) - (0.14 x Defensive Rating) - (0.44 x Usage%) + 13.8

For Dwight Howard, this season, we get:
37.6 Minutes per game
27.2% Usage
113 Offensive Rating
94 Defensive Rating

=(0.035 x 37.6) + (0.43 x 0.272 x 113) - (0.14 x 94) - (0.44 x 27.2) + 13.8
=1.316 + 13.21648 - 13.16 - 11.968 + 13.8
=3.2        --- (although it's 3.45 if you use the more precise numbers below)

[For stat-heads, the actual coefficients are:  Min/G: 0.034853, ORTG*Usg/100: 0.434141, DRTG: -0.13995, USG%: -0.43613]


So for the 2010-2011 regular season, I have calculated the predicted "Net Efficiency." This is simply our estimate of how much a player adds to his team's point differential per 100 possessions of offense & 100 possessions of defense. Also, I have calculated the estimated "Wins Added" by multiplying their efficiency by the % of minutes they played, and converting that number into a wins estimate (how many wins an average team would have gained from their performance).

Here are the results for 2010-2011 (Regular Season - players with 500 or more minutes).