This topic is resumed: see below.

In my opinion a team is said to have a possession when it has interrupted and complete control of the ball. A possession ends when a field goal is attempted, when there is a turnover, on a jump ball, or after a free throw that is not the first of two. That's ok?


   Translation & Links:  ebastats - the Basketball statistics forum

This post RESUMES the topic


About the Concept: As you can read at our Possessions Analysis:
Definition of Possession:  the time your team gets the ball, all the way up until the other team gets it back. At least for the purpose of this number, offensive rebounds don’t add possessions. This is comprehensible, since to determine the cost of a turnover, for instance, we want to know what the total chance there was that you’d score some points before the other team got the ball back. That includes getting offensive rebounds, since the turnover eliminates the possibility of getting second chance points just as it did first chance points.

About the Formula: The total number of possessions a team has can be calculated as

Field Goals Made + Opp Def. Rebounds + Turnovers + Up to the Line for 2/3-points)

Meanwhile another formulas use the coefficient "FTA / 2" or "FTA*0.4", etc., the eBA System uses the exact number of possession ended "up to the line" for 2 or 3 throws.

Discussion: This formula, with the "up to the line" coefficient, was basically created because we felt it was a better evaluation of offensive and defensive efficiency than to count stats like total rebounds, or total points scored or allowed or divide the free throws attempts by estimates number of "2" or multiply by "0.4". 
About the rebounds formulas, you hear talk about "win the rebound war, win the game" what is in general true, but not always.  The addition of the 3 point shot to the game of Basketball causes to re-estimate the value the formula as well.  If in short a team has the opportunity to score at least 3 points on every possession, instead of two, so  we have added an additional variable into the equation. 
An additional way of thoughts is that by using FGA as a loss of possession, a possession is lost every time a ball is shot.  As a result a new possession starts with an offensive rebound.  This works against a good offensive rebounding team because it punishes their Points / Possession evaluation. 
To resume this question,  as said above, from the moment there is discrepancy between the number of free throws attempted per game so that the FTA/2 or FTA*0.4 is not always an evaluation according to the rules, since on any given night the number of 1, 2, or 3 free throw attempts for each fouled possession will vary.  The eBA System uses the exact number of possession ended "up to the line" for 2 or 3 throws as a better measure regardless of the total number of attempts.   

Commentary: Consequently many coaches are now using what is called Points/Possession, or Turnovers/Possession.  The Pts/Poss. is an impartial reliable stat when all things are considered. 
However it doesn't take into account the optimal pace as which a team plays.   Team A that receives 90 points may actually produce a better defensive efficiency than team B that allowed 80 points:  in a fast paced game, Team A received 90 points but in 90 possessions.  This means their defensive efficiency was 1.0.  Team B on the other hand received only 80 points but in a much slower paced game in 60 total possessions.  That is a defensive efficiency of 1.3 actually worse than team A who allowed ninety points.

Points per possession is a completely good stat but what is more important is to break it down into ranges such as an offensive or defensive efficiency when you score or allow 90-100 points, 80-90, 70-80 and so forth.  The parameter we will find is that the team have better offensive and defensive efficiency ratings when he plays at its team's optimal pace.  The eBA System do this break down in his "Quarters Reports", when the game is analyzed every 5 minutes by separate.

This summary resumes this topic and will be completed at the "Statistics" chapter of the eBA Basketball Statistics Analysis System.  Another Basketball statistics topics you'll find at the Basketball Statistics Discussions section of our eBA Stats.com site.

    Brian Denver - eBA Stats Team - The Basketball Statistics Analysis

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