Points per Possession

Question from our old Forum

I’ve been reading up on advance stats a lot the last few weeks and found that apparently I have been tracking points per possession a bit different then the common approach. My method was very simple:

(Points scored * 100) / Possessions

A slightly more advanced approach for finding total possessions:

 POSSt = FGAt + 0.44 × FTAt – OREBt + TO

I’m not sure it affected my team a whole lot as I think we got about four offensive rebounds the entire season.  Regardless, is anyone else tracking this?  What is your formula?

Answer:

Points per Possession is Points / Possessions.

Points per 100 Possessions is (Points scored * 100) / Possessions.

POSSt = FGAt + 0.44 × FTAt – OREBt + TO
is the formula for accurately measuring the total number of possessions.

Pts / (FGAt + 0.44 × FTAt – OREBt + TO) will equal points per possession, but there is no need to use this formula to make the calculation, just use the easier one listed above if you are after points per possession.

The purpose of POSSt = FGAt + 0.44 × FTAt – OREBt + TO is to make clear that FGAt, FTAt and TO are the 3 ways that possessions end and that OREBt extend possessions and allow additional FGAts, FTAts and TOs within that same possesion of the ball so it requires the OREBts to be subtracted to keep an accurate count of team “possessions”.

Possessions + OREBts would be an accurate count of total “plays”.

The .44 is the factor in the total possessions formula that helps to pretty accurately measure how many possessions were used during the total of FT attempts.

Often a player will get 2 FTAs. Sometimes just 1, sometimes 3. Sometimes it will be a technical foul and not be the end of a possession. Sometimes a missed FTA won’t end the possession because of an offensive rebound or a foul of the offensive rebounder. The historical average for possessions used up is 0.44 × FTAt.

The little t was meant as a placeholder for a specific team’s name, the name of the offense, while they used o where necessary for the opposing team.

But as a generic formula you could also just think of it as meaning team total or it could ignored or dropped.

The big messages here with the detailed possession formula are that offensive rebounds have to be backed out to help get the official number of possessions used by a team and avoiding over-counting possessions, and  that .44 * FTA is the standard / good  enough approximation for how many possessions were  used by free throw activity  (instead of having to count those possessions manually as the game goes on or afterwards by looking at video).