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APBRmetrics
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Harold Almonte
Joined: 04 Aug 2006
Posts: 616
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 Posted: Tue Feb 12, 2008 7:34 pm Post subject: |
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About the first part, I think you're not "so" confused, since you were one of the charters in that study.
About the second part I compared two similar defensive rebounding players advantage situations (7% or 14% against 32%) where the difference is more about boxing out and blocking than any other thing. How to quantify that, I could not to know it. But it's obvious that defensive rebounders are assisted (some kind of boxing out help) on about 60% of those rebounds. Not to mention that some of the help sometimes is given by the opponents not going in to rebound, even not being blocked at all. |
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cherokee_ACB
Joined: 22 Mar 2006
Posts: 157
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| Posted: Wed Feb 13, 2008 4:08 am Post subject: |
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Another approach to study if the increase in OR% is a matter of effort or of long rebounds is to look at FT misses in close end of game situations. We can assume the effort is there in this case, can't we?
BTW, I'm in the long rebounds camp. Did you know that the under-75% FT shooters grab their own miss in 2.7% of cases, versus 1.5% for good shooters? |
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Harold Almonte
Joined: 04 Aug 2006
Posts: 616
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| Posted: Wed Feb 13, 2008 9:11 am Post subject: |
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| Quote: | | under-75% FT shooters grab their own miss in 2.7% of cases, versus 1.5% for good shooters? |
Those are not so invisible numbers. It's logical in the sense of more long rebounds, and also that a lower FThrowing selfesteem leads to a more intuition for the shooter that he will miss, and then the more effort to make up for his fail. But, I also think that a big number of those rebounds come from deflections from the real fight. |
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Chicago76
Joined: 06 Nov 2005
Posts: 98
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| Posted: Thu Feb 14, 2008 12:21 am Post subject: |
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| cherokee_ACB wrote: | Another approach to study if the increase in OR% is a matter of effort or of long rebounds is to look at FT misses in close end of game situations. We can assume the effort is there in this case, can't we?
BTW, I'm in the long rebounds camp. Did you know that the under-75% FT shooters grab their own miss in 2.7% of cases, versus 1.5% for good shooters? |
Poor shooters could do a better job of rebounding their own miss for a couple of reasons:
1-The long rebound theory, or
2-Poor FT shooters have a higher concentration of big men who happen to be really good offensive rebounders.
A quick look at the players with the best ORB% last year with 500+ minutes:
23 of 25 were in the "poor" shooter camp. David Lee and Ilgauskas were the only "good" shooters in the bunch. |
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Ben F.
Joined: 07 Mar 2005
Posts: 391
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| Posted: Thu Feb 14, 2008 11:55 pm Post subject: |
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More on this front: I wondered whether any players had artificially inflated DR% totals because they got a lot of boards after FTs. So I looked at what percentage of a player's defensive rebounds came after FTs, and the results are interesting. Here are the top 30, limited to players with 50 or more defensive boards (data through January 31st):
| Code: | Player DR ftDR ftDR%
1 Jackson,Stephen 137 31 22.6%
2 Thornton,Al 92 20 21.7%
3 Hayes,Jarvis 87 18 20.7%
4 Davis,Ricky 156 32 20.5%
5 Johnson,Amir 51 10 19.6%
6 Moon,Jamario 206 36 17.5%
7 Blatche,Andray 123 21 17.1%
8 Powell,Josh 59 10 16.9%
9 Walker,Antoine 91 15 16.5%
10 Bass,Brandon 122 20 16.4%
11 Dudley,Jared 55 9 16.4%
12 Humphries,Kris 117 19 16.2%
13 Kirilenko,Andrei 154 25 16.2%
14 Williams,Shawne 74 12 16.2%
15 Childress,Josh 106 17 16.0%
16 Boozer,Carlos 362 58 16.0%
17 Villanueva,Charlie 144 23 16.0%
18 Smith,Craig 130 20 15.4%
19 Millsap,Paul 163 25 15.3%
20 Mourning,Alonzo 59 9 15.3%
21 Skinner,Brian 139 21 15.1%
22 Foster,Jeff 226 34 15.0%
23 Brown,Kwame 101 15 14.9%
24 Gooden,Drew 279 41 14.7%
25 Jefferson,Richard 143 21 14.7%
26 Lee,David 239 35 14.6%
27 Collison,Nick 248 36 14.5%
28 Thomas,Kurt 249 36 14.5%
29 Barnes,Matt 147 21 14.3%
30 Magloire,Jamaal 63 9 14.3% |
A lot of swingmen at the top, surprisingly. What shocked me the most was that this many players have between 1/7th and 1/5th of their rebounds come off of FTs. That seems like a really high number.
I'm not sure we should discount the ability to rebound off of free throws entirely, but I do think it perhaps should be separated from other rebounds. It makes big men who don't get a lot of these FT defensive boards look better than previously thought. DeSagana Diop has a DR% of 18.6% so far this year, but only 4.3% of his DRs are off of FTs. I estimate that if he rebounded off of FTs at the rate that Drew Gooden does, for example, he'd be at a DR% of 19.9%. Similarly, if Duncan rebounded at the rate that Boozer did off of FTs he'd have a DR% of 27.9% instead of 25.3%.
Here are the list of the 15 non-guards who have the lowest FT DR% (same limits as before):
| Code: | Player DR ftDR ftDR%
1 Young,Thaddeus 69 2 2.9%
2 Harrington,Al 185 6 3.2%
3 Anthony,Carmelo 181 6 3.3%
4 Balkman,Renaldo 59 2 3.4%
5 Dunleavy,Mike 231 8 3.5%
6 Green,Jeff 143 6 4.2%
7 Diop,DeSagana 138 6 4.3%
8 Stojakovic,Peja 127 6 4.7%
9 Bosh,Chris 250 12 4.8%
10 Duncan,Tim 331 17 5.1%
11 Chandler,Tyson 347 19 5.5%
12 Haslem,Udonis 311 17 5.5%
13 Collins,Jarron 53 3 5.7%
14 Nesterovic,Rasho 80 5 6.3%
15 Przybilla,Joel 228 14 6.1% |
The differences are really large, between the Diop to Przybilla group (4-6%) and the Magloire to Blatche group (14-17%). Anybody have theories as to why the gap is so big? That just seems weird. Why do some players get huge amounts of rebounds off of the FT and some don't get any at all? Do they just let their teammates get the boards? And what to make of all the Utah players (Boozer, Kiri and Millsap) being so high up?
Last edited by Ben F. on Fri Feb 15, 2008 11:53 am; edited 1 time in total |
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Eli W
Joined: 01 Feb 2005
Posts: 402
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| Posted: Fri Feb 15, 2008 12:46 am Post subject: |
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Good stuff. Part of the Utah effect probably comes from the fact that they foul so much. More FT DRB opportunities. To get around that kind of thing you'd want to control for opponent FG% and opponent FTA (which you could do by looking at DRB rates rather than totals).
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Ben F.
Joined: 07 Mar 2005
Posts: 391
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| Posted: Fri Feb 15, 2008 1:01 am Post subject: |
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| Good point, more fouls obviously makes a lot of sense, I should have thought of that. That being said, I don't think that explains all the variance among players (I can't imagine the difference in fouls adds up to that much, and even then you have players like Diop and Przybilla who are relative hackers on the lowest end of the spectrum). I'll try and add in the FT rebound opportunities tomorrow. |
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Mike G
Joined: 14 Jan 2005
Posts: 3630
Location: Hendersonville, NC
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| Posted: Fri Feb 15, 2008 6:38 am Post subject: |
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I think I'm detecting some coaches in the high-ftDR% list: Let your bigger guards and SF rebound on FT, so your bigs can already be up the floor.
Also a lot of guys off the bench. Who's least likely to be on the floor after a foul? -- the guy who just fouled. His replacement may get an easy rebound then.
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Harold Almonte
Joined: 04 Aug 2006
Posts: 616
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| Posted: Fri Feb 15, 2008 9:32 am Post subject: |
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| Yeah. Scorer bigs seem to appear in the lower half of the list. Some coachs wouldn't want too much body contact for them. And to put them nearer the other end than the opponent big could be also a kind of strategy. |
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Ben F.
Joined: 07 Mar 2005
Posts: 391
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| Posted: Fri Feb 15, 2008 4:01 pm Post subject: |
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| Eli W wrote: | | Part of the Utah effect probably comes from the fact that they foul so much. More FT DRB opportunities. To get around that kind of thing you'd want to control for opponent FG% and opponent FTA (which you could do by looking at DRB rates rather than totals). |
OK, I now did just that. I found the league average FT rebound opportunities per minute and then essentially said: if the player had the league average opportunities and rebounded off of FTs at the same rate that he has so far this year, what percentage of his rebounds would be off of FTs then? Basically, it just controls for what you brought up - teams that foul more, or players that have more opportunities to get those FT rebounds. For example, Carlos Boozer had 122 FT defensive rebound opportunities, but if he had the league average he would have only had 101.3. He rebounded 58 of those 122 (47.5%), so if he had the league average opportunities he would have rebounded 48.11. We then divide 48.11 by his total rebounds to find the percentage of his defensive boards that came off of FTs (13.3%, without adjustment it was 16.0%).
So here is the list of the top 30 ftDR% players, adjusted for opportunities (again limited to players with at least 50 defensive rebounds):
| Code: | Player ftDR%
1 Ely,Melvin 24.9%
2 Davis,Ricky 22.4%
3 Thornton,Al 21.9%
4 Jackson,Stephen 20.4%
5 Magloire,Jamaal 20.0%
6 Armstrong,Hilton 19.4%
7 Moon,Jamario 19.1%
8 Childress,Josh 17.1%
9 Blatche,Andray 16.7%
10 Powell,Josh 16.4%
11 Skinner,Brian 16.3%
12 Humphries,Kris 15.9%
13 Smith,Craig 15.9%
14 Aldridge,LaMarcus 15.6%
15 Hayes,Jarvis 14.9%
16 Perkins,Kendrick 14.4%
17 Jefferson,Richard 14.2%
18 Bogut,Andrew 14.1%
19 Thomas,Kurt 14.0%
20 Swift,Stromile 13.9%
21 Milicic,Darko 13.9%
22 Gooden,Drew 13.9%
23 Kirilenko,Andrei 13.8%
24 Mourning,Alonzo 13.7%
25 Wright,Dorell 13.7%
26 Villanueva,Charlie 13.6%
27 Miller,Brad 13.4%
28 Boozer,Carlos 13.3%
29 Murphy,Troy 13.2%
30 Gasol,Pau 13.2% |
The list is still pretty similar. You can see Boozer and Kiri still on the list, albeit a little farther down.
On the low end, players like Rasho (8.7%) and Przybilla (8.7%) move up, most likely for the reason Mike G brings up: they foul and then get removed, so they have less opportunities than average to get FT rebounds. Diop (5.3%), however, stays in place, as does Chris Bosh (6.0%) and Tim Duncan (6.5%) for the most part.
Other good rebounding bigs who don't get a large share off of FTs:
Udonis Haslem (6.8%)
Zaza Pachulia (6.9%)
Nazr Mohammed (7.4%)
Sean Williams (7.6%)
Andrew Bynum (7.7%)
Joakim Noah (7.8%)
The spread is still very interesting, even adjusted, and I do wonder: is this a skill or something that should be taken out to find a player's "true" rebounding rate? And should it only be done on the defensive end (as I've done here) or do we think offensive rebounds off of FTs aren't really skill either? |
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Conan the Librarian
Joined: 03 Sep 2007
Posts: 35
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| Posted: Fri Feb 15, 2008 4:22 pm Post subject: |
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| Ben F. wrote: | | A lot of swingmen at the top, surprisingly. |
I don't find that surprising in the least. Swingmen will more often be guarding players on the perimeter, decreasing their chance of grabbing a rebound off a missed FG. On free throws, they obviously aren't guarding anyone, and are only focused on getting the rebound or boxing out near the basket. So, intuitively, it seems to follow that they would have a higher % of rebounds off FT's than big men. |
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Ben F.
Joined: 07 Mar 2005
Posts: 391
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| Posted: Fri Feb 15, 2008 5:07 pm Post subject: |
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| Conan the Librarian wrote: | | I don't find that surprising in the least. Swingmen will more often be guarding players on the perimeter, decreasing their chance of grabbing a rebound off a missed FG. On free throws, they obviously aren't guarding anyone, and are only focused on getting the rebound or boxing out near the basket. So, intuitively, it seems to follow that they would have a higher % of rebounds off FT's than big men. |
The reason I thought it was surprising is that I would think you would have two big men on either block and they would collect a lot of those "gimme" rebounds, rather than the swingmen. |
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Conan the Librarian
Joined: 03 Sep 2007
Posts: 35
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| Posted: Fri Feb 15, 2008 5:15 pm Post subject: |
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| Ben F. wrote: | | The reason I thought it was surprising is that I would think you would have two big men on either block and they would collect a lot of those "gimme" rebounds, rather than the swingmen. |
True. I can't explain Ricky Davis or Jarvis Hayes in that list, but guys like Jackson, Dudley, Kirilenko, Thornton. and even Josh Childress, play a fair amount at the 4 for their teams, so on free throws they would be positioned on the low block. |
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Chicago76
Joined: 06 Nov 2005
Posts: 98
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| Posted: Fri Feb 15, 2008 7:42 pm Post subject: |
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| Ben F. wrote: | | The spread is still very interesting, even adjusted, and I do wonder: is this a skill or something that should be taken out to find a player's "true" rebounding rate? And should it only be done on the defensive end (as I've done here) or do we think offensive rebounds off of FTs aren't really skill either? |
The questions you ask are very interesting. DRBs off FTAs are a function of:
-the number of times the opponent goes to the line (which you've controlled for), and
-where you happen to be positioned along the lane/elsewhere during a FTA.
I think this falls in line with MikeG's theory of coaching/strategic issues. For example, if an opponent's big man is on the line, it might make sense to pull one of your bigs away from the basket and place him at center court to start a quick transition rather than have him stationed under the basket. The big man at the line is not as big of a reb. threat from 15 feet away, so a defensive team could get away with placing a swing man on the lower block to collect the ball and push up court.
The lack of extra DRBs for some guys could relate to strategic choices made in this manner.
Compare this to DRBs from the run of play. They're a function of:
-FG misses by the opponent (again controlled for by looking at DRB%), and
-how close a player is to the basket on a miss. How close someone is to the basket is governed by the strategic choices coaches and teams make about defensive assignments. Some teams might camp a big man out near the lane, while others require that the player to contest more perimeter shots.
The guy who gets to camp out near the lane all game benefits the same way a guy who is always on the lower block for a FT does. Neither are necessarily better rebounders.
To get a player's "true" DRB rate, I think we would need to adjust for floor position on both FTs and FGs. If you were to separate DRB% from FGs and FTs, you would separate floor position biases for both scenarios, however, I'm not sure that either would be a better indication of rebounding ability. |
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