A metric that combines offensive PER, defensive PER, and plus/minus to give an overall evaluation of a player's value. The final number is weighted in the following proportion: 2/3 PER and 1/3 plus/minus.
Simple Rating is a single-number evaluation metric developed by NBA statistician Roland Beech of 82games. Interestingly, Beech is not an advocate of single-number ratings, but without going into far greater analytical detail, this metric is likely the most accurate available in terms of getting a quick read on a player's "worth".
As an example, let's say a player's PER is 17.5, while his opponent's PER is 10.3 (the opponent is determined by looking at who is playing the same position for the other team while the offensive player is in the game). The net result of this is +7.2. Next, our player has a +5.8 on court, with a -3.7 off court, for a net of +9.5. By weighting these values as described in our definition, the simple rating for this player would be +7.9.