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Which is the most important rebound
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Chronz1



Joined: 22 May 2006
Posts: 201

PostPosted: Tue May 30, 2006 4:31 am    Post subject: Which is the most important rebound Reply with quote

Offensive rebound or defensive rebound?

I always used to say offensive rebounds are more valuable because they are harder to achieve but this guy says defensive rebound is just as important because they prevent offensive rebounds.

Another question why is a offensive rebound with .7 on the PER scale wheras a defensive rebound is worth only .3

If they are equally important shouldnt they both be worth .5
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edijorj



Joined: 21 Apr 2006
Posts: 30

PostPosted: Tue May 30, 2006 6:43 am    Post subject: Reply with quote

For a team an orb and a drb are equally important (for the reason you give). However for evaluating an individual, an orb is much more important. Why? Because the regressions say so. At http://www.uncg.edu/eco/rosenbaum/NBA/winval2.htm Dan Rosenbaum finds that for the average player the value of a drb is almost equal to zero. I think more recently he has found a higher value using a slightly different regression model, but the value is still much less than the value of an orb.

An interpretation of these results is that players other than the rebounder (for example the one guarding the player who missed) deserve a very large share of the credit for a drb, so even though a drb is as valuable for the team as an orb, the player who catches a drb deserves much less credit. Another interpretation (not incompatible with the first) is that the number drbs mostly reflect the the game plan (for example the game plan was for Rodman to be the rebounder), but that orbs, because they are so much harder to catch, actually reflect rebounding ability.

I think 0.7 for an orb and 0.3 for a drb is about right. I usually use 0.6 and 0.27.
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mrgold



Joined: 29 Apr 2006
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PostPosted: Tue May 30, 2006 1:15 pm    Post subject: Reply with quote

Orebounds are greater than droubounds cuz their harder to get. If a player who grabs an offensive rebound doesnt grab it than the other team will almost certainly gain possesion. However, if a player is not in position to get a defensive rebound, someone else on his team will most likely get it. The value of an individual getting a rebound is equal to the liklihood that their action caused their team to retain possesion as opposed to lose it. Since most rebounds are defensive an offensive rebound is of much more valuable.
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cherokee_ACB



Joined: 22 Mar 2006
Posts: 157

PostPosted: Tue May 30, 2006 3:21 pm    Post subject: Reply with quote

This 82games.com article
http://www.82games.com/rebounds.htm
tells that most offensive rebounds are contested, while nearly half of deffensive rebounds are not. This is consistent with the roughly two-to-one ratio between the value of an offensive rebound relative to a deffensive rebound that PER and other rating systems use. I'm not saying that uncontested rebounds have no value (positioning is key), but that a good amount of deffensive rebounds are grabbed essentially because the ball goes to the player hands, and not the other way around. That's why you won't see any player with a rebound rate lower than 3%.
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kjb



Joined: 03 Jan 2005
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Location: Washington, DC

PostPosted: Tue May 30, 2006 3:23 pm    Post subject: Reply with quote

Why is an offensive rebound more valuable because it's harder to get? What if what's most valuable for the offense is to get gack on defense and prevent a fastbreak basket instead of expending any effort to get an offensive rebound?
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Ed Küpfer



Joined: 30 Dec 2004
Posts: 787
Location: Toronto

PostPosted: Tue May 30, 2006 4:31 pm    Post subject: Reply with quote

Here'a a different way of saying the same thing:



The graph shows the relationship between a player's REB% and his team's. The red points are defensive rebounds, the blue points offensive. The panels divide the data among 9 player positions.

Look at the regression lines. Notice the slope for OR% is higher than that of DR%? That tell us that for each unit increase in a player's OR% he raises his team's OR% by greater amount that an increase in player DR% raises his team's DR% -- that is, a player's effect on his team's rebounding is greater on ORs than DRs. My number's suggest that each OR is twice as valuable as a DR for frontcourt players, more for the other players. (In fact, I see a slope not significantly different from zero on guard's DR%.)
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alphamale



Joined: 03 May 2006
Posts: 67

PostPosted: Tue May 30, 2006 8:29 pm    Post subject: Reply with quote

I don't have any stats to back this up but I've seen Dennis Rodman grab numerous rebounds both offensive and defensive, that weren't contested. He managed to anticipate where the rebound was going and got to that position before anyone else. Of course, there are the usual rebounds that just so happen to come to you and you're in the right place at the right time.

It's kind of like how making uncontested shots is less impressive than making contested shots. But maybe I player just managed to outsmart the defense to be in that position in the first place.
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Analyze This



Joined: 17 May 2005
Posts: 364

PostPosted: Wed May 31, 2006 2:29 am    Post subject: Reply with quote

WizardsKev wrote:
Why is an offensive rebound more valuable because it's harder to get? What if what's most valuable for the offense is to get gack on defense and prevent a fastbreak basket instead of expending any effort to get an offensive rebound?
Because the chance that he is in a good scoring position after grabbing the OR is high?
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kjb



Joined: 03 Jan 2005
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PostPosted: Wed May 31, 2006 9:14 am    Post subject: Reply with quote

Analyze This wrote:
WizardsKev wrote:
Why is an offensive rebound more valuable because it's harder to get? What if what's most valuable for the offense is to get gack on defense and prevent a fastbreak basket instead of expending any effort to get an offensive rebound?
Because the chance that he is in a good scoring position after grabbing the OR is high?


Figuring this out would take a few calculations. Yes, the chance of scoring after an offensive rebound is likely to be pretty high. How much higher? (I don't know the answer off the top of my head.) Of course, there's only about a 3 in 10 chance of getting the offensive rebound at all.

On the other hand, there's the fact that the opposition could get a fastbreak, which is going to have a fairly high conversion rate. How much higher than a typical halfcourt possession? And, not all defensive rebounds result in a fastbreak. So, there are a number of push-pulls, and there's likely a way to balance the tradeoffs -- sending two bigs to the offensive glass (they're more likely to get an offensive board than the littles) while the other three get back.

Question: Have there been any high-quality offenses throughout league history that shot poorly, but relied heavily on offensive rebounding? The Wizards the past few years come to mind -- this season they were 21st in efg, 6th in orb%, and had the 6th best offense. They also had few turnovers and shot lots of FT. Does anyone know of other similar examples?
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edijorj



Joined: 21 Apr 2006
Posts: 30

PostPosted: Wed May 31, 2006 10:51 am    Post subject: Reply with quote

Quote:
Because the chance that he is in a good scoring position after grabbing the OR is high?


This is not a reason. Denying your opponent a good scoring position is as important as getting a good scoring position.
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deepak



Joined: 26 Apr 2006
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PostPosted: Wed May 31, 2006 1:29 pm    Post subject: Reply with quote

WizardsKev wrote:

Question: Have there been any high-quality offenses throughout league history that shot poorly, but relied heavily on offensive rebounding? The Wizards the past few years come to mind -- this season they were 21st in efg, 6th in orb%, and had the 6th best offense. They also had few turnovers and shot lots of FT. Does anyone know of other similar examples?


The 1998 Chicago Bulls? Maybe 9th in offense in 1998 doesn't count as "high quality", but they were only ranked 21st in shooting while 2nd in offensive rebounding. Like the Wizards, they also did a good job limiting turnovers to become an above average offensive team.
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kjb



Joined: 03 Jan 2005
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PostPosted: Wed May 31, 2006 1:35 pm    Post subject: Reply with quote

deepak_e wrote:
WizardsKev wrote:

Question: Have there been any high-quality offenses throughout league history that shot poorly, but relied heavily on offensive rebounding? The Wizards the past few years come to mind -- this season they were 21st in efg, 6th in orb%, and had the 6th best offense. They also had few turnovers and shot lots of FT. Does anyone know of other similar examples?


The 1998 Chicago Bulls? Maybe 9th in offense in 1998 doesn't count as "high quality", but they were only ranked 21st in shooting while 2nd in offensive rebounding. Like the Wizards, they also did a good job limiting turnovers to become an above average offensive team.


Well, considering that the Bulls won 62 regular season games plus the title that year, I'd say their offense was good enough. Interesting to note the relatively low turnovers, though. This year, for example, the correlation between turnover rate and offensive rating was about double that of offensive rebounding percentage and offensive rating (roughly .4 to .2). Neither a strong correlation because we're looking only at parts of offensive rating. (efg was about .8.)
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Analyze This



Joined: 17 May 2005
Posts: 364

PostPosted: Thu Jun 01, 2006 1:48 am    Post subject: Reply with quote

edijorj wrote:
Quote:
Because the chance that he is in a good scoring position after grabbing the OR is high?


This is not a reason. Denying your opponent a good scoring position is as important as getting a good scoring position.


Some players will try to get the defensive rebound to. Without that the fastbreak can not start in a rebounding situation. The rebounders who crash the defensive glass are mostly not standing at half court. So if for example two players attack the offensive glass and three watch out for the fast break...
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exile



Joined: 05 Feb 2006
Posts: 6
Location: Melbourne, Australia

PostPosted: Thu Jun 01, 2006 3:58 am    Post subject: Reply with quote

Speaking of offensive and defensive rebounds, has there been any statistical anaylsis done (82games or otherwise) that tell us where the rebounds are going to? Preferably after a certain shot? (i.e. jumpers from say, 16 feet, often are longer rebounds than shots from 5 feet)
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Mike G



Joined: 14 Jan 2005
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Location: Hendersonville, NC

PostPosted: Thu Jun 01, 2006 5:54 am    Post subject: Reply with quote

If on 2 consecutive opponent possessions, 2 teammates are in position to get the d-rebound, they will still only total 2 (at most) between them. It's exactly because d-reb are more often 'shared' that they aren't accrued as often as they might be (by a given individual).

This is analagous to the illusion that assists to an inside player are more 'valuable' than those to a perimeter shooter. High-% shots are more likely to be converted -- retroactively, into assists -- and thus the passer in fact gets more credit when he hits the likelier scorers.

Rarely do players 'team up' for an o-reb. There is no sharing, nor deferring to a 'designated rebounder' (Rodman). D-reb totals represent only some fraction of the total reb a player could have if he were greedy.
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