Possession Differential

[GoldenStateGM]

Just put together a new (or maybe not, I have no idea) statistic, called possession differential.
It looks at a teams RPG, SPG, and TOPG, and adds them up, and gives a +/- number of possessions a team has compared their opponents.

Team   PPG Diff   Reb Diff   APG Diff   SPG Diff   TOPG Diff   Possession Diff
Warriors   11.5   3.1   3.8   2.8   3.8   9.7
Nets   12.5   3.3   3.3   1.4   2   6.7
Pacers   9.8   3.3   -2.1   1.6   1.7   6.6
Hornets   10.1   4.9   3   0.4   1.3   6.6
Kings   7.3   6.2   2.7   -1   0.5   5.7
Heat   6.5   4.7   6   0.2   0   4.9
Raptors   4.1   1.6   0.6   0   1.5   3.1
Nuggets   8.1   5.9   5.5   -1.5   -1.5   2.9
Clippers   4.5   5.7   -1   -1.1   -2   2.6
Jazz   1.6   1.7   1.5   0.8   -0.1   2.4
Pistons   -1.1   3.3   -1.8   -1   -0.9   1.4
Grizzlies   5.3   -2.4   4.1   1.3   2.3   1.2
Wizards   -3.8   1   0.6   0.7   -0.6   1.1
Magic   -1.9   -0.1   -2.3   0   0.1   0.0
Trailblazers   -1.1   0.8   -4.3   -0.4   -0.5   -0.1
Bucks   -0.8   0.7   -1   -0.2   -1.2   -0.7
Spurs   -5.4   -2.8   -1.3   1.2   0.7   -0.9
Celtics   -6.4   0.6   -1.4   -1   -0.5   -0.9
Timberwolves   -1.2   -3.5   -0.5   1   1.3   -1.2
Cavs   -0.4   -2.4   -1.6   -0.1   1   -1.5
Rockets   -4.6   -4.4   -1.7   0.3   2   -2.1
Knicks   -5.2   4.4   -2.9   -2.4   -4.3   -2.3
Suns   -8.7   -0.6   -1.4   -1   -2.3   -3.9
Mavericks   -5.2   -4.2   -2.7   -0.6   -0.5   -5.3
Supersonics   -4.8   -6.5   -1.7   0.4   -0.4   -6.5
Hawks   -7.5   -6.3   -0.3   -0.1   -1.1   -7.5
76ers   -2.1   -5.4   0.5   -1.5   -0.9   -7.8
Bulls   -9.6   -5.1   -2.9   -0.8   -2.1   -8
Lakers   -12.1   -9.1   -2.2   0   0.6   -8.5

[GoldenStateGM]

The top 5 teams are the Warriors, Nets, Hornets, Pacers, and Kings.

(BTW, the top 5 team in PPG differential are the Nets, Warriors, Pacers, Hornets, and the Nuggets, with the Kings in sixth, showing a very good correlation between posessions and PPG differential)

The Top 5 teams in rebounding differential are the Kings, Hornets, Nuggets, Clippers, and the Heat.

The Top 5 teams in steals differential are the Warriors, Pacers, Nets, Grizzlies, and the Spurs.

The Top 5 team in turnover differential are the Warriors, Nets, Rockets, Grizzlies, and the Pacers.

I find this to be a very interesting stat, since more possessions, on average, gives a team a much better chance of winning.

[HawksGM]

good, stuff, I'd like to see this again closer to the playoffs, I think it would be interesting to see how the top 5 teams in this statistic do in the playoffs

[KingsGM-old]

At least i'm top 5 in something.

Good work.

p.s. did you take into consideration the pace maybe?

[CelticsGM]

Very interesting analysis ...

... and almost impossible to "read". I really hate the fact that these boards don't allow the posting of tables.


But back to the fact: I disagree slightly how possessions are calculated. And due to the fact that offensive/defensive boards are not available seperately there can't be a "true" # of possessions.

Basically the number of possessions is shot attempts + turnovers + non-shooting fouls from the opponent. Now it's pretty impossible to seperate "and-1" ft attempts from non-shooting ft attempts, but i'm working on a formula with fouls per game ...
 

[GoldenStateGM]

Oh, FG% and OFG% are also major drivers in winning (and the reason why the Nuggets are one of the top 5 teams in the league, since I think they might have the biggest differential in those percentages)

But back to the fact: I disagree slightly how possessions are calculated. And due to the fact that offensive/defensive boards are not available seperately there can't be a "true" # of possessions.

Makes no difference.  An Offensive rebound is a possession as much as a Defensive rebound.  Big difference is that I would bet there is a higher FG% on offensive rebounds.  But that info is unavailable in the sim.

BTW, possessions is an unfair stat, using FGA as a measure.  Pace would be a significant driver in that using that stat.  A team that uses a very fast pace should have more attempts...

I thought Offensive fouls are considered turnovers, but good chance I am wrong

Kings, I took nothing into account.  These numbers are right off of the team statistics page.

[NetsGM]

Now it's pretty impossible to seperate "and-1" ft attempts from non-shooting ft attempts

Possessions are generally defined as:
(fgm+(0.4*ftm)+opponents_defensive_rebounds+turnovers)

the 0.4 is the free throw variable.

0.5 would be assuming everything is two free throws per possession.  That's not true, since there are and-1's and technicals.  That constant is generally between 0.4 and 0.44.

You then use Points Per 100 Possessions to define offensive and defensive efficiency and compare them both between games and between teams.

Since points per game is largely dependent on pace, it's not a good true measure.  I.e. you could shoot 50% against the Pistons and still only score 85 points because they slow down the pace.  Your points would be much lower than your true efficiency.  You also can't look at just fg%, since that ignores rebounds and turnovers.

PP100P takes all that into effect.  It determines your total possessions (as I defined above), divides your points by your possessions, multiplies it by 100.  This can then be compared between teams  even among 2 teams with drastically different paces, i.e. the Pistons and Spurs can be compared to the Suns in offensive and defensive efficiency.

For example:
76ers offensive and defensive points per 100 possessions:
http://www.phillyarena.net/stats.php

What that allows you to do is view a game log of points per 100 possessions and compare games to each other.  For example, just comparing points on the Knicks games vs. the Raptors games wouldn't work, since the Knicks typically slow the ball game down while the Raptors....well, don't.  So this allows you to compare different games without regard to pace.

[CelticsGM]

Possessions are generally defined as:
(fgm+(0.4*ftm)+opponents_defensive_rebounds+turnovers)

the 0.4 is the free throw variable.

That variable does help me a lot. Thanks

But again, i guess i have a mental lapse there, i don't see rebounds being a factor at all in the # of possessions:
This is my basical assumption: Every possession ends with either
- a shot attempt (that can be successful, missed, blocked, whatever) or
- a turnover or
- a shooting foul without continuation (all "and-1" foul possession are already processed in the succesful FG attempts) which lead to freethrows

There is no other end of possession. An off board leads to a new possession, true, but that possession again will end with either of the three above ...

[CelticsGM]

oh yeah, my brain had a highlight: bods formula above regards offensive rebounds as keeping the same possession.

That would be meaning if you shoot, get the off board, try three putbacks, still get the off board, call timeout, run the clock for 23 seconds, shoot, get the off board again ... you're still in the same possession whereas my formula would give you the 6th possession already.


Now i feel a possession is a possibility to score and 6 FG attemps therefor have to be six possessions.

[NetsGM]

I just edited the post after you replied, so I'll quote myself:

You then use Points Per 100 Possessions to define offensive and defensive efficiency and compare them both between games and between teams.

Since points per game is largely dependent on pace, it's not a good true measure. I.e. you could shoot 50% against the Pistons and still only score 85 points because they slow down the pace. Your points would be much lower than your true efficiency. You also can't look at just fg%, since that ignores rebounds and turnovers.

PP100P takes all that into effect. It determines your total possessions (as I defined above), divides your points by your possessions, multiplies it by 100. This can then be compared between teams even among 2 teams with drastically different paces, i.e. the Pistons and Spurs can be compared to the Suns in offensive and defensive efficiency.

For example:
76ers offensive and defensive points per 100 possessions:
http://www.phillyarena.net/stats.php

What that allows you to do is view a game log of points per 100 possessions and compare games to each other. For example, just comparing points on the Knicks games vs. the Raptors games wouldn't work, since the Knicks typically slow the ball game down while the Raptors....well, don't. So this allows you to compare different games without regard to pace.

Offensive rebounds aren't used in the statistic, but they do have a bearing on your efficiency, as if you get more attempts with the same amount of possessions your total points output should increase (if you ever convert those offensive rebound opportunities, that is).

[CelticsGM]

According to my formula the # of possession looks a bit different:

Code:

            OWN     OPP     POSS          OPP            OPP						
Team        POSS    POSS    DIFF   PPS    PPS     FG%    FG%						
76ers       106.9	110.1	-3.2	1.16	1.14	.452	.435
Bucks       111.9	111.9	+0.1	1.13	1.12	.440	.445
Bulls       108.1	110.8	-2.8	1.18	1.22	.439	.467
Cavs        110.6	111.6	-0.9	1.16	1.18	.448	.460
Celtics     112.0	109.2	+2.8	1.05	1.18	.424	.457
Clippers    112.2	110.8	+1.5	1.22	1.14	.453	.441
Grizzlies   110.2	112.9	-2.6	1.21	1.12	.462	.429
Hawks       107.1	110.8	-3.6	1.13	1.18	.437	.456
Heat        109.0	106.4	+2.6	1.18	1.14	.463	.435
Hornets     110.2	109.2	+1.0	1.14	1.05	.450	.410
Jazz        109.9	109.6	+0.3	1.16	1.14	.448	.441
Kings       108.0	105.5	+2.6	1.18	1.11	.444	.427
Knicks      113.4	111.5	+1.9	1.12	1.17	.440	.451
Lakers      107.2	110.6	-3.4	1.10	1.23	.431	.465
Magic       109.7	108.5	+1.2	1.12	1.14	.429	.444
Mavs        110.2	113.7	-3.5	1.15	1.17	.443	.446
Nets        112.0	111.7	+0.3	1.20	1.08	.451	.411
Nuggets     109.1	107.3	+1.7	1.22	1.13	.481	.429
Pacers      112.7	112.7	 0.0	1.23	1.11	.451	.422
Pistons     113.8	110.4	+3.3	1.15	1.18	.439	.449
Raptors     110.1	109.1	+1.0	1.14	1.13	.445	.436
Rockets     109.3	110.7	-1.5	1.15	1.16	.429	.464
Spurs       109.6	110.0	-0.4	1.11	1.17	.427	.461
Suns        108.1	106.4	+1.7	1.13	1.23	.435	.480
Sonics      108.4	112.9	-4.6	1.11	1.13	.434	.430
Wolves      106.3	107.5	-1.1	1.16	1.17	.438	.459
Blazers     111.9	110.8	+1.1	1.10	1.13	.429	.433
Warriors    110.3	108.1	+2.1	1.16	1.14	.450	.419
Wizards     110.5	108.4	+2.0	1.08	1.15	.423	.439

POSS ... # of own possessions
OPP POSS ... # of opponent possessions
POSS DIF ... possession differential
PPS ... points per shot
OPP PPS ... opponents points per shot

The Pistons lead the way here generating 3.3 more possession (=opportunities to score) than their opponents, followed by Celtics, Heat, Kings and Warriors. So why are the Celtics so bad then?

Well, shooting at a pathetic 42% clip means they convert far less of their possessions into points, as evident by their league worst 1.05 PPS.
The Grizzlies on the other hand are a weaker rebounding team allowing the opponent 2.6 more possessions per game but since they are converting much much better (1.22 PPS) they win more.

It's that simple.

And it also means, my Celtics simply have to shoot a higher % and all will be good ...