Basketball Reference site, has a Net Rating Stat in order to calculate the differential between Offensive and Defensive Rating. The Formula is simple:
Net Rating = Offensive Rating – Defensive Rating
,and according to site’s glossary “NRtg -- Net Rating; an estimate of point differential per 100 possessions”.
So, NRtg actually illustrates qualitative if a Team has a better Offense than Defense.
Same differential formula can be applied respectively to all available Stats.
Net differential to each statistic category will calculate the comparison between Offense and Defense. Hence, immediately it can be evaluated the quality of the Offense versus the Defense. A Positive Number means a better Offense, while a Negative Number means a worse Offense.
So, Net Differential can be applied to:
1. 4 Factors (Dean Oliver)
2. Team versus Opponent Stats
For example, about TOV% in 4 Factors: A Team can be League Average in TOV%, but it can be on the bottom in Defensive TOV%. So, actually in TOV% Net Differential the Team is not in an average position, but rather in a lower one.
Let’s take Sacramento Kings at 2018-19 Season. They are 5th in TOV%, 4th in Defensive TOV%, while 2nd overall in the League at the differential of TOV% at Offense versus Defense.
Below follows an example of illustrating ‘Difference between Four Factors’. With Green highlight is the Positive impact, while with Red the negative: