 |
APBRmetrics
The statistical revolution will not be televised.
|
| View previous topic :: View next topic |
| Author |
Message |
gabefarkas
Joined: 31 Dec 2004
Posts: 1313
Location: Durham, NC
|
 Posted: Mon Feb 16, 2009 4:29 pm Post subject: |
 |
|
| Ilardi wrote: | | Of course, I think you could ask them of any metric: they all describe what has happened, not what will happen. That being said, despite the moderate degree of year-to-year fluctuation in defensive APM, there's still a great deal of stability on balance (e.g., KG is still a highly-rated player this year on defensive APM, as are Camby, Chuck Hayes, Yao, Kirilenko, Aldridge, etc.). |
Dr Ilardi - can you explain what the part in bold means? To me, "stability" and "balance" are essentially synonyms, no? |
|
| Back to top |
|
 |
Ilardi
Joined: 15 May 2008
Posts: 265
Location: Lawrence, KS
|
| Posted: Mon Feb 16, 2009 4:53 pm Post subject: |
|
|
| gabefarkas wrote: | | Ilardi wrote: | | Of course, I think you could ask them of any metric: they all describe what has happened, not what will happen. That being said, despite the moderate degree of year-to-year fluctuation in defensive APM, there's still a great deal of stability on balance (e.g., KG is still a highly-rated player this year on defensive APM, as are Camby, Chuck Hayes, Yao, Kirilenko, Aldridge, etc.). |
Dr Ilardi - can you explain what the part in bold means? To me, "stability" and "balance" are essentially synonyms, no? |
By stability I mean "temporal stability" - i.e., the value of the rating tends to be fairly similar each time it's measured across multiple time points (e.g., from one season to the next).
By on balance I simply mean "all things considered" (i.e., as everything is weighed in the balance).
P.S. Please feel free to call me Steve in this forum (unless you happen to be one of my undergrads here at KU). |
|
| Back to top |
|
|
bchaikin
Joined: 27 Jan 2005
Posts: 690
Location: cleveland, ohio
|
| Posted: Mon Feb 16, 2009 11:30 pm Post subject: |
|
|
Mentioning players/coaches opinions without their arguments makes no sense. It's not important what they think...
perhaps you should read some of the books of bill james. he was of the belief that the opinions of those who saw players play the most (sportswriters and coaches) was of great import, to be used in conjunction with stats analysis, although admittedly he was speaking about baseball not basketball, and in a historical context...
For example Kobe Bryant is allegedly, according to coaches/players nominations/awards the all-NBA caliber defender through the whole last decade. Even though some of his seasons(especially after Shaq has left him) he didn't really bother defending opposing players or giving any effort whatsoever so he could save his energy for the Lakers' poor-at-the-time offense.
this by chance the same kobe bryant that's been named to the all-D team 8 times in his career (6 all-D 1st team, 2 all-D 2nd team)? just out of curiosity, are there any other players voted to the all-D team, even 1/2 the amount of times bryant was, that in your opinon didn't defend opposing players or give any effort on defense whatsoever?...
Players recording high number of steals are often overrated. That's exactly what happened to Paul last season.
often, huh?... ok...
chris paul is on pace to get 200+ steals in a season for the 2nd time. here is a list of the nba players that have gotten 200+ steals in a season more than once in their careers over the past 30 seasons:
mookie blaylock
maurice cheeks
clyde drexler
rickey green
eddie jordan
michael jordan
fat lever
gary payton
scottie pippen
michael ray richardson
alvin robertson
john stockton
if, as you say, high steal players are often overrated as defenders, would you care to share your expertise with this discussion group as to which of these players were not very good defenders, especially in the years they got their 200+ steals?...
There's no way he could be 7th best defender in the league. Not even close.
no? you think that's too low? maybe 6th, 5th, or 4th best?...
First off, small guys don't have that kind of influence on team defense that bigs have.
from 1993-94 to 1996-97, for a 4 year stretch, the atlanta hawks had the league's 5th best/lowest pts/poss allowed on defense in the league. only new york, chicago, seattle, and portland had better defenses...
that atlanta team those 4 years has just the 11th best/lowest eFG% allowed on defense, just the 15th highest BS/g, and had a defensive rebounding percentage of available rebounds that was just 18th in the league. yet they had the league's 5th best defense...
a key reason why was that over these 4 years the hawks averaged the 2nd most steals per game among all teams (9.5 ST/g)...
these 4 seasons their 6-1 and 185 lb PG mookie blaylock got more steals than any other player in the league, 836 steals. he averaged 209 steals a year...
only once in these 4 years did a hawks player block more than 150 shots in a season (mutombo, 96-97, his only season with the hawks in this 4 year stretch), and only two other times did a player block even 100 shots (andrew lang and jon konchak)...
blaylock played over 3600 more total minutes than any other hawks player these 4 years, was named to the all-D team all 4 seasons (twice 1st, twice 2nd team), and the only other hawks player to be named to the all-D team during this time was mutombo in 96-97....
i'd say small guy mookie blaylock had quite an influence on one of the league's better defensive teams over a good 4 year stretch...
Second part is rebounding, you can have Kidds, Rondos all you want, but without rebounding bigs your team is weak on the boards anyway - just look at the Kidd's-era Nets. Given that defending the paint and rebounding are two of the crucial elements of team defense, small guys have much less effect on it(stats also confirm it).
you mean the 01-02 and 02-03 new jersey nets team that jason kidd led to the finals two seasons in a row? that nets team was the league's best team defensively (lowest pts/poss allowed on defense) in the league those two years combined. yet that team for those two seasons had just the 9th best rate of defensive rebounding percentage of available rebounds, just the 7th best rate of defensive rebounds per game, and just the 13th best rate of BS/g...
but guess what? they were 5th best in steals per game, and guess who got the 2nd most total steals of all players in the league these two seasons? yep, jason kidd, with 354 steals - which was over 120 more steals than what the next best nets player got (kittles with 231)...
Being a realist, Paul wasn't even close to deserve 7th place on DPOTY list and even him being a candidate is pretty ridiculous.
evidently those who voted for the DPOY think differently than you. perhaps they aren't as real as you...
You count the steal as a defensive stop as if gambling wasn't causing total defensive breakdowns. We can only suppose how many steals per failed gamblings Paul has had, but it's sure he had some.
what about all those times paul went for a steal, didn't get it, but forced a turnover or a bad pass? or are you under the impression that every single time a player goes for a steal but doesn't get it it's bad for his team?...
Being a defender you care about staying in front of the opponent first, not to draw help from your teammates, not letting the defense collapse.
being a defender you care about stopping your opponent from scoring, first and foremost. getting a steal not only stops your opponent from scoring, it stops him from shooting in the first place...
You simply eliminate many of the important factors to team defense in order to make your points look more legitimate. On purpose or not...
oh it's on purpose...
...it's not fair.
all's fair in love and apbrmetrics... |
|
| Back to top |
|
|
bastillon
Joined: 04 Nov 2008
Posts: 55
|
| Posted: Tue Feb 17, 2009 1:02 am Post subject: |
|
|
I'm just saying that your steal numbers aren't worth too much, if you don't know how many times the defense suffered from his gambling.
As for small vs big conversation I thought it would be obvious... Look at the awards, look at the teams without interior defense, the DRtg, APM +/-. It's all evidence. Really surprised me that you're even questioning bigs impact. |
|
| Back to top |
|
|
haralabob
Joined: 11 Apr 2007
Posts: 27
|
| Posted: Tue Feb 17, 2009 1:40 pm Post subject: |
|
|
Although I enjoy reading the back and forth and heated debates, I couldn't help myself on this subject.
Adjusted plus minus and defensive counterpart statistics shed a little light on who is or isn't a good defensive player. But obviously they don't tell the whole story, if you want to know how good Chris Paul was on defense in 2007-08 chart every single NOR defensive possession.
Here are some numbers;
The guy he was guarding scored .87 points per offensive action, (on 1203 actions).
The best number on his team was .80 held by Rasual Butler (313 actions)
Pargo's numbers were 1.01 on 620 actions. |
|
| Back to top |
|
|
gabefarkas
Joined: 31 Dec 2004
Posts: 1313
Location: Durham, NC
|
| Posted: Tue Feb 17, 2009 2:07 pm Post subject: |
|
|
| Ilardi wrote: | | gabefarkas wrote: | | Ilardi wrote: | | Of course, I think you could ask them of any metric: they all describe what has happened, not what will happen. That being said, despite the moderate degree of year-to-year fluctuation in defensive APM, there's still a great deal of stability on balance (e.g., KG is still a highly-rated player this year on defensive APM, as are Camby, Chuck Hayes, Yao, Kirilenko, Aldridge, etc.). |
Dr Ilardi - can you explain what the part in bold means? To me, "stability" and "balance" are essentially synonyms, no? |
By stability I mean "temporal stability" - i.e., the value of the rating tends to be fairly similar each time it's measured across multiple time points (e.g., from one season to the next).
By on balance I simply mean "all things considered" (i.e., as everything is weighed in the balance).
P.S. Please feel free to call me Steve in this forum (unless you happen to be one of my undergrads here at KU). |
In that case, it seems the issue with Chris Paul is even more exaggerated, as he went from one extreme to the other, no? |
|
| Back to top |
|
|
Ilardi
Joined: 15 May 2008
Posts: 265
Location: Lawrence, KS
|
| Posted: Tue Feb 17, 2009 2:35 pm Post subject: |
|
|
| haralabob wrote: | Although I enjoy reading the back and forth and heated debates, I couldn't help myself on this subject.
Adjusted plus minus and defensive counterpart statistics shed a little light on who is or isn't a good defensive player. But obviously they don't tell the whole story, if you want to know how good Chris Paul was on defense in 2007-08 chart every single NOR defensive possession.
Here are some numbers;
The guy he was guarding scored .87 points per offensive action, (on 1203 actions).
The best number on his team was .80 held by Rasual Butler (313 actions)
Pargo's numbers were 1.01 on 620 actions. |
Those are fascinating numbers, but I have a few questions (if you don't mind) that might help me with their interpretation:
1) what does and does not count as an "offensive action" (i.e., how is the term operationalized)?
2) is your points-per-offensive-action stat normed by position? (presumably, some positions on offense engage in a higher proportion of non-scoring actions [e.g., setting screens, handoffs to regain dribble, "hockey assists, etc,"] than others)
3) what counts as the "player being guarded"? if a pg picks up a pf on a screen, is he now guarding him for the purposes of your stat? what if he tries to cover the pf's man in transition because the pf didn't get back? what if he's part of a double-team of someone else's man? or a zone? or a trap?
4) how did Paul's .87 ppoa in 07-08 rank among other 1's in the league?
5) how did the points-per-offensive-action rating of Paul's teammates vary when he was on-versus-off the court? Since Paul's overall adjusted plus-minus in 07-08 was negative, it would seem likely that his teammates' defensive ppoa numbers must have increased when he was on the court (assuming Paul's own .87 number is regarded as quite low)?
Many thanks in advance for any clarification you can provide.
P.S. Where can the rest of us get ahold of your points-per-action numbers?
Last edited by Ilardi on Tue Feb 17, 2009 2:40 pm; edited 1 time in total |
|
| Back to top |
|
|
Ilardi
Joined: 15 May 2008
Posts: 265
Location: Lawrence, KS
|
| Posted: Tue Feb 17, 2009 2:38 pm Post subject: |
|
|
| gabefarkas wrote: | | Ilardi wrote: | | gabefarkas wrote: | | Ilardi wrote: | | Of course, I think you could ask them of any metric: they all describe what has happened, not what will happen. That being said, despite the moderate degree of year-to-year fluctuation in defensive APM, there's still a great deal of stability on balance (e.g., KG is still a highly-rated player this year on defensive APM, as are Camby, Chuck Hayes, Yao, Kirilenko, Aldridge, etc.). |
Dr Ilardi - can you explain what the part in bold means? To me, "stability" and "balance" are essentially synonyms, no? |
By stability I mean "temporal stability" - i.e., the value of the rating tends to be fairly similar each time it's measured across multiple time points (e.g., from one season to the next).
By on balance I simply mean "all things considered" (i.e., as everything is weighed in the balance).
P.S. Please feel free to call me Steve in this forum (unless you happen to be one of my undergrads here at KU). |
In that case, it seems the issue with Chris Paul is even more exaggerated, as he went from one extreme to the other, no? |
No question: he's an outlier. It'll be interesting to see to what extent his high rating this season holds up through 82 games & playoffs. |
|
| Back to top |
|
|
bastillon
Joined: 04 Nov 2008
Posts: 55
|
| Posted: Tue Feb 17, 2009 3:56 pm Post subject: |
|
|
| haralabob wrote: | Although I enjoy reading the back and forth and heated debates, I couldn't help myself on this subject.
Adjusted plus minus and defensive counterpart statistics shed a little light on who is or isn't a good defensive player. But obviously they don't tell the whole story, if you want to know how good Chris Paul was on defense in 2007-08 chart every single NOR defensive possession.
Here are some numbers;
The guy he was guarding scored .87 points per offensive action, (on 1203 actions).
The best number on his team was .80 held by Rasual Butler (313 actions)
Pargo's numbers were 1.01 on 620 actions. |
It's just his man, I don't see you measured how his play affected the whole team and it's the case right here. |
|
| Back to top |
|
|
haralabob
Joined: 11 Apr 2007
Posts: 27
|
| Posted: Tue Feb 17, 2009 4:24 pm Post subject: |
|
|
Hey Steve;
what does and does not count as an "offensive action" (i.e., how is the term operationalized)?
Roughly - We consider, shots, turnovers, and drawn shooting fouls as offensive actions - we also factor in drawn non shooting fouls in a different metric.
In other words when you are actively guarding the player or engaged, if he takes a shot, turns the ball over or draws a shooting foul you are are charged as the defensive player.
what counts as the "player being guarded"? if a pg picks up a pf on a screen, is he now guarding him for the purposes of your stat? what if he tries to cover the pf's man in transition because the pf didn't get back? what if he's part of a double-team of someone else's man? or a zone? or a trap?
The initial numbers I gave you were just for all unfiltered possessions. If i add the following criteria;
No Zone defense
No Transition fastbreak defense
No excessive Help Defense.
The numbers look like this;
Chris Paul .91 on 782 actions
Rasual Butler .78 on 201 actions
Jannero Pargo on 1.02 actions.
Basically what we are looking at are all halfcourt offensive actions.
We only remove excessive help defense that is considered above average, an example of this would be actions where Chandler or another help defender came over and blocked or severely altered the shot.
how did Paul's .87 ppoa in 07-08 rank among other 1's in the league?
Here is a sampling of 5 pgs filtered with the above criteria.
Chauncey Billups .77 469
Jason Kidd (w/ Dallas) .81 on 349
Jameer Nelson .96 on 577
Devin Harris (w/Dallas) .98 on 277
Derek Fisher 1.00 on 670
how did the points-per-offensive-action rating of Paul's teammates vary when he was on-versus-off the court? Since Paul's overall adjusted plus-minus in 07-08 was negative, it would seem likely that his teammates' defensive ppoa numbers must have increased when he was on the court (assuming Paul's own .87 number is regarded as quite low)?
At this time I am not currently interested in distributing or releasing any of the defensive data I have acquired.
Haralabob |
|
| Back to top |
|
|
haralabob
Joined: 11 Apr 2007
Posts: 27
|
| Posted: Tue Feb 17, 2009 4:52 pm Post subject: |
|
|
| bastillon wrote: |
It's just his man, I don't see you measured how his play affected the whole team and it's the case right here. |
Correct, its just his man, if you wanted to know how his play impacted the rest of the team I could give you the number of times the player he was guarding got past him and was picked up by a secondary help defender.
Conversely I could also give you numbers on where he came over to help on defense.
Or you could come up with creative pairings to see how players X's numbers looked when A, B (and on) are on the court.
There are other limitations, for instance each player you are guarding has an offensive "ev" or expected value for each action. The numbers I provided don't factor offensive 'ev' into the equation.
To better understand this consider a player who spent their whole season guarding Jared Jeffries vs someone who spent their whole season guarding LeBron James.
I have an adjusted defensive number that accounts for this and is more accurate. .
Haralabob |
|
| Back to top |
|
|
Ben
Joined: 13 Jan 2005
Posts: 266
Location: Iowa City
|
| Posted: Tue Feb 17, 2009 4:55 pm Post subject: |
|
|
| haralabob wrote: | | bastillon wrote: |
It's just his man, I don't see you measured how his play affected the whole team and it's the case right here. |
Correct, its just his man, if you wanted to know how his play impacted the rest of the team I could give you the number of times the player he was guarding got past him and was picked up by a secondary help defender.
Conversely I could also give you numbers on where he came over to help on defense.
Or you could come up with creative pairings to see how players X's numbers looked when A, B (and on) are on the court.
There are other limitations, for instance each player you are guarding has an offensive "ev" or expected value for each action. The numbers I provided don't factor offensive 'ev' into the equation.
To better understand this consider a player who spent their whole season guarding Jared Jeffries vs someone who spent their whole season guarding LeBron James.
I have an adjusted defensive number that accounts for this and is more accurate. .
Haralabob |
So could you summarize your assessment of how Chris Paul stacks up defensively both this year and last year? |
|
| Back to top |
|
|
Neil Paine
Joined: 13 Oct 2005
Posts: 774
Location: Atlanta, GA
|
| Posted: Tue Feb 17, 2009 4:59 pm Post subject: |
|
|
| Ben wrote: |
So could you summarize your assessment of how Chris Paul stacks up defensively both this year and last year? |
Yeah, I was gonna say: Haralabos, do you think (according to your numbers) the quality of CP's defense has changed in any way between 07-08 & 08-09? Is there any way to explain his wild shift in adjusted +/- from a "bad" defender to a relatively good one? |
|
| Back to top |
|
|
haralabob
Joined: 11 Apr 2007
Posts: 27
|
| Posted: Tue Feb 17, 2009 5:11 pm Post subject: |
|
|
| Quote: | Yeah, I was gonna say: Haralabos, do you think (according to your numbers) the quality of CP's defense has changed in any way between 07-08 & 08-09? Is there any way to explain his wild shift in adjusted +/- from a "bad" defender to a relatively good one?
|
No I'd say that there isn't. The numbers I gave were for 07-08. His defensive numbers for 07-08 were above average for the PG position, his numbers for this year are also above average for the PG position. |
|
| Back to top |
|
|
Neil Paine
Joined: 13 Oct 2005
Posts: 774
Location: Atlanta, GA
|
| Posted: Tue Feb 17, 2009 5:19 pm Post subject: |
|
|
| haralabob wrote: | | No I'd say that there isn't. The numbers I gave were for 07-08. His defensive numbers for 07-08 were above average for the PG position, his numbers for this year are also above average for the PG position. |
I have to admit, this is a strange case. My eyes tell me he hasn't really done anything differently, either. I wonder, could this have simply been the "perfect storm" of small sample sizes, multicollinearity, and the Hornets' substitution patterns playing tricks on the adjusted +/- method? |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
