## Re: A womans perspective on offensive rebounds

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• Great information being provided here and by Stuart. How do I use this info? It s explained somewhat here:
Message 1 of 2 , Dec 11, 2001
Great information being provided here and by Stuart.

How do I use this info? It's explained somewhat here:

http://www.rawbw.com/~deano/articles/JordanvsOlaj.html

My formula has changed slightly from then (that was written in '96)
and the theory has advanced. But at a conceptual level, here is what
goes on:

Offensive rebounds are an indirect contributor to a scoring
possession, somewhat like an assist, though an assist is even more
direct. An offensive rebound contributes to a scoring possession by
giving the offense another _chance_ to score, not a score itself.
For example, I'm looking at a recent Blazer-Sonic game (where
Portland won easily) where Portland shot 45/81 from the field and had
12 offensive rebounds. If you look only at how Portland did without
offensive rebounds, they scored on 54% of their "possessions" (called
a "Play %") = [FGM + (1- (1-FT%)^2)*0.4*FTA ] / [FGA + 0.4 * FTA +
TO], where FGM = 45, FGA = 81, FTA = 28, TO = 11, FTM = 20 (ft% =
0.714). If you look at how Portland did _with_ offensive rebounds,
they scored on 61% of their possessions ("floor %") FGM + (1- (1-FT%)
^2)*0.4*FTA ] / [FGA - OR + 0.4 * FTA + TO]. Basically, those 12
offensive rebounds turned into 6 new scoring possessions (~12 *
0.536, though my accounting says that some are probably duplicates).
I disperse that credit to individual scoring possessions according to
their offensive rebounds. I remove that credit evenly from all
player scoring possessions according to the assumption that they all
evenly benefit from team offensive rebounds.

Where all this detailed accounting from John and Stuart helps is in a
few areas. First, that play % is suggested to be a little bit higher
after offensive rebounds. If I adjust that in the formula, it gives
more credit to offensive rebounders than I currently give. Second, I
have assumed in my accounting even distribution after the offensive
rebound -- equal likelihood that anyone on the floor could score.
That definitely seems to not be the case from the detailed work.
This affects two things. It means that offensive rebounders are less
likely to have their made shots assisted on -- because more of their
made shots are after OR's, which are not assisted on. That helps
them. Second, I give half credit to the offensive rebounder and half
to "the rest of the team" on scoring possessions created by an
offensive rebound. (The ORFIG on the website said 0.1, but I worked
out the theory better to say that 0.5 works best in combination with
other changes I made.) This detailed work from John and Stuart is
suggesting that the "rest of the team" typically consists of that
offensive rebounder sticking it back. I need to work through the
theory to see whether I need to change that half credit to something
else. I don't think so, but I don't know.

Again, outstanding work you guys are doing. At some time in the not
too distant past, I felt like there was a serious lack of data to
help do detailed analysis. This is changing that. Now the
limitation is time to do the analysis.

Dean Oliver

--- In APBR_analysis@y..., "John Maxwell" <John.Maxwell@C...> wrote:
> Okay, maybe not a woman's perspective, but a perspective on the
women's game
>
> Over the past week or two, I've been trying to log all of the
offensive
> rebounds from last season in the WNBA to determine the importance
of an
> offensive rebound to a team's offense. When I'm done, I'll have
team and
> individual figures as well, but for now I thought I'd share what
I've got on
> a league-wide level.
>
> So far I've logged 2,012 of 5,056 offensive rebounds. My xl sheets
note who
> grabbed the rebound, if the player that grabbed the rebound took the
> subsequent shot or turned the ball over, the kind of shot (two-
pointer,
> three-pointer, free throws), the number of points derived from the
offensive
> rebound, if the player's teammates took the subsequent shot or
turned the
> ball over, the kind of shot, and the number of points derived from
the
> offensive rebound.
>
> Some things that aren't logged -- Whether or not the player that
grabbed the
> offensive rebound put the shot back up immediately or took the shot
later in
> the possession as part of the offense, the kind of shot that was
rebounded,
> the shot clock at the time of the rebound, if the player who
grabbed the
> offensive rebound assisted on her teammate's subsequent field goal.
I'm sure
> there are other things that I can't think of that might have been
worth
> looking into, but that's what I can think of off the top of my
> anybody has any suggestions as to if any of these things or other
items
> should be logged, I can look into it when I go back through to
check my work
>
> Dean, I'm particularly interested to see how this information might
alter
> the credit given for an offensive rebound in your formulas.
>
> So with 40 percent of the rebounds logged, here's what I've found.
>
> In the WNBA . . .
>
> 57.2 percent of activity following the offensive rebound is
generated by the
> offensive rebounder. The offensive rebounder shoots the ball on 78
percent
> of the activity that she generates, gets fouled and goes to the
free throw
> line on 13 percent of the activity she generates and turns the ball
over the
> remaining 9 percent of the time.
>
> The remaining 42.8 percent of the activity following the offensive
rebound
> is generated by the offensive rebounder's teammates. Her teammates
shoot the
> ball on 75 percent of the activity they generate, get fouled and go
to the
> free throw line on 10 percent of the activity they generate and
turn the
> ball over 15 percent of the time.
>
> ----------------- Poss*--- FGA --- FTA --- TO -------3GA
> Orebounder --- 1150 --- 78% ---- 13% ---- 9% --------4%
> Teammates ---- 856 ---- 75% ---- 10% --- 15% ------14%
>
> I threw in the percentage of three-point field goal attempts there
at the
> end.
>
> Success Rates
> Offensive rebounders are successful on 48.1 percent of their field
goal
> attempts, 23.4 percent of their three-point field goal attempts and
70.7
> percent of their free throws. An offensive rebounders teammates are
> successful on 41.6 percent of their field goal attempts, 36.8
percent of
> their three-point field goal attempts and 68.0 percent of their
free throw
> attempts.
>
> Percentages
> -------------------- FG ----- 3G ----- FT ---- Pts/Poss
> Orebounder ----- 48.1 --- 23.4 --- 70.7 ------ 0.944
> Teammates ----- 41.6 ---- 36.8 --- 68.0 ----- 0.833
> Combined ------- 45.4 --- 33.9 --- 69.7 ------ 0.897
>
> Lg Avg ---------- 41.1 ---- 33.6 --- 74.1 ----- 0.815
> Lg Avg-Oreb --- 40.5 ---- 33.5 --- 74.8 ----- 0.805
>
> Lg Avg stands for the overall league average. Lg Avg-Oreb stands
for the
> league average minus the possessions affected by an offensive
rebound - sort
> of a "First Shot" percentage. Since I haven't logged all the
rebounds, I
> just assumed the same percentages for the remaining 3000 offensive
rebounds
> to get a ballpark figure.
>
> Pts/Poss stands for points per possession. I counted each offensive
rebound
> as a new possessions despite the fact that most of us don't
consider it to
> be one since the ball never changes hands. I did this because it
was the
> only way I could compare apples to apples with regards to how I was
logging
> the offensive rebound data.
>
> Thoughts:
> Much of the data backs up what you might guess about the importance
of an
> offensive rebound.
>
> Free Throw Percentages - the free throw percentages following an
offensive
> rebound are lower than the league average because taller players
are the
> ones grabbing the offensive rebounds, and taller players are,
> the players who don't shoot as well from the free throw line. Dawn
Staley is
> the WNBA's career free throw percentage leader, but she only
grabbed 11
> offensive rebounds last season.
>
> The offensive rebounder hits a higher percentage of her shots than
the
> league average due to her proximity to the basket. She also takes
vastly
> fewer three-point field goal attempts for this same reason.
>
> The offensive rebounder's teammates hit a higher percentage of
three point
> field goal attempts because everybody's attention is diverted
towards the
>
> Teams score more points per possession off of offensive rebounds
than "First
> Shot" possessions, even those possessions that are affected by the
offensive
> rebounder's teammates, although not by as much.
>
> Here are the hard numbers
> ----------------- Poss --- FG-FGA -- 3G-3GA -- FT-FTA ---- Pts -- TO
> Orebounder -- 1150 --- 430-894 ----- 11-47 ---- 215-304 --- 1086 --
107
> Teammates ---- 856 --- 266-639 ----- 64-174 --- 117-172 ---- 713 --
132
> Combined ---- 2006* -- 696-1533 --- 75-221 --- 332-476 -- 1799 ---
239
>
> *The possessions don't add up to the total number of offensive
rebounds
> because a handful of offensive rebounds were credited right at the
end of
> halves or the game where no additional shots were taken.
>
> That's all for now.
>
> John Maxwell
> Director of Public Relations
> Charlotte Sting
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