SoTD: Bargnani's defensive numbers over 4 years

[andreafan]

Btw i am a raptor fan first, and an andrea fan second.

[BorisDK1]

I'm sorry to weigh in on such a controversial topic for my first post here, but I find much of the argumentation here overly facile. The people blindly insisting Bargnani's defense is somehow acceptable are oblivious to the fact that he just played over 2,800 minutes for what is the 21st worst defense in league history - well, since 1978 when we first had the requisite data, at any rate (measured by points allowed / 100 possessions worse than league average) so obviously he has to be lacking something.

On the other hand, the discussion of primary cause of the defense from the OP and others is equally facile. I find using on/off court data as indicators of cause to be fallacious (post hoc, ergo propter hoc) and further, probably not using the best data available. I believe the best data available is through a method called Project Defensive Score Sheet (spelled out in Dean Oliver's Basketball on Paper), in which all the stops produced and scores allowed are tabulated for all the players (and uncontested action as well) and the individual Defensive Rating generated from that is the best way of generating defensive metrics. That data is not currently kept in boxscores by the NBA, so that data has to be kept manually. I did that for this past year - every single possession, all 82 games.

This past year, Bargnani played ~ 2800 minutes. In those minutes, he forced 553.5 missed field goal attempts (not including blocks), 75.5 turnovers (not including steals) and 64 missed free throws, to go along with his 389 defensive rebounds, 111 blocks and 25 steals. He allowed 404 field goals and 188 made free throws to go along with those. That translates to a stop% of .552 while facing 19.2% of the opponents' possessions defensively, giving him an ultimate Defensive Rating of 110.0 points allowed / 100 possessions faced, which was second-best of anybody on our team playing more than 350 minutes, behind only Amir Johnson (.551 stop% @ 22.8% DPoss%, 109.5 DRat) and tied with Bosh (.545 stop% @ 19.5% DPoss%, 110.0 DRat). (All the team defensive numbers used to generate the DRat only come from the games in which the individual actually play.) Now, that's a far cry from being the hapless yutz that some want to present him as. To be sure, you would hope your center is better than that - and certainly facing more possessions. But it's far better than some want to portray.

Who was the worst on our team? Jose. He had a stop% of .376 @ 18.8% DPoss%, 118.3 DRat. To put that in some context, uncontested action (i.e. uncaused action, being guarded by thin air) had a stop% of .357 @ 7.9% DPoss%, 115.2 DRat. Further, when Jose missed time, the team became significantly better, to the tune of about 4 points / 100 possessions. When Andrea missed his two games (granted, a tiny sample size) the team actually played at around the same level defensively it normally did. Why didn't it get considerably better, if Andrea were the cause of the defensive badness by himself?

I think the answer is significantly more complex than "blame Andrea". I think the people who want to do that, unfortunately, are using guesswork generated by on/off court analysis from 82games.com instead of direct analysis. I suppose that's becasue there is a dearth of popularly published data for defensive metrics, and because many people struggle with defensive analysis. This tends to be expressed by assigning the vast majority of blame/credit for defensive performance to the big men, which I personally believe is an extremely naive view of defense. And then we have the blaming of Triano's defensive tactical beliefs for the team's defensive woes, which further is untenable.

I think the problems lay in having so many players (Andrea, Hedo, Jose) on the court who are at considerable disadvantage of speed and quickness, and consequently the team had absolutely no pressure on the basketball at any time. Pressure on the ball is the absolute foundation of your defense, and without it nothing you try will work.

EDIT: Another thing I forgot to mention...the on/off court data had considerable flux as the season fell apart for this team. Jose was somewhere around +12 points allowed/100 possessions after he got hurt, and that improved somewhat as he came off the bench. Andrea was a slight plus or a neutral factor for most of the year until the team totally collapsed after the All-Star break. This adds a lot of doubt to using on/off court data to explain cause, because the data did fluctuate so much. There's much better information to use that gives direct data, not indirect.

[hsb]

Either way this team will stink until someone emerges as the new VC/Bosh.

The team stunk with those two guys too. Have to leave the preputual loop of finding that one marketable guy and generate a winning team from now on.

[Tony_Montana]

lol @ keeping that data for every game this season. do you mind posting yer game log spreadsheet?

[BorisDK1]

lol @ keeping that data for every game this season. do you mind posting yer game log spreadsheet?

You can download the final spreadsheet here in .pdf format. I don't have the spreadsheet available online yet, as it is a huge file with splits sorted in other workbooks. I'd be happy to post that this week sometime, if you'd like.

One caveat: there are editing mistakes in the team stats in the final page of the document, there, and haven't had a chance to correct them. I did post every single game's stats at raptorspace.com, if you have any doubts. My username there is BorisD.

Nice try with the "lol", though. lol @ u? I'm too old for the childish "pic or didn't happen" thing.

[Indeed]

These stats are totally meaningless. Its like a good d-man in hockey with a -10 rating on an average team.

Hrm, I don't know much about hockey, but isn't it usually a low scoring game? It would be stupid to look at on/off, +/- sort of stats in say a game like soccer...there is too much statistical variance and not enough data to wash it away.

The wonderful thing about basketball is that there is a GINORMOUS amount of data, since each game is usually 90+ possessions. Think about it, that is roughly 7400 possession per season for a team. That is a crapload of data...you can learn a lot from it if you try.

I don't think you can simply minus both On/Off
DRtg = Points Allowed * 100 / Possessions:
DRtgDiff = [Points Allowed On] * 100 / [Possessions On] - [Points Allowed Off] * 100 / [Possessions Off]

You need to know the Possessions (Pace) correctly in order to do a minus.
[Edit: Sorry, I mean you can minus them, but if your base possessions are different, then it means their strategy has changed, thus the minus becomes less meaningful. Rather, knowing the sample size of base possessions and the reason it changed would be a more in depth understanding then just knowing a change in number.]

Besides, Points Allowed is simply +/-, it looks better when it is in an average, but to determine how much point opponent can score doesn't lead to how good/bad he is as a defender, but as a team (hint: Bargnani is a really bad help defender).

[supersub15]

I'm sorry to weigh in on such a controversial topic for my first post here, but I find much of the argumentation here overly facile. The people blindly insisting Bargnani's defense is somehow acceptable are oblivious to the fact that he just played over 2,800 minutes for what is the 21st worst defense in league history - well, since 1978 when we first had the requisite data, at any rate (measured by points allowed / 100 possessions worse than league average) so obviously he has to be lacking something.

On the other hand, the discussion of primary cause of the defense from the OP and others is equally facile. I find using on/off court data as indicators of cause to be fallacious (post hoc, ergo propter hoc) and further, probably not using the best data available. I believe the best data available is through a method called Project Defensive Score Sheet (spelled out in Dean Oliver's Basketball on Paper), in which all the stops produced and scores allowed are tabulated for all the players (and uncontested action as well) and the individual Defensive Rating generated from that is the best way of generating defensive metrics. That data is not currently kept in boxscores by the NBA, so that data has to be kept manually. I did that for this past year - every single possession, all 82 games.

This past year, Bargnani played ~ 2800 minutes. In those minutes, he forced 553.5 missed field goal attempts (not including blocks), 75.5 turnovers (not including steals) and 64 missed free throws, to go along with his 389 defensive rebounds, 111 blocks and 25 steals. He allowed 404 field goals and 188 made free throws to go along with those. That translates to a stop% of .552 while facing 19.2% of the opponents' possessions defensively, giving him an ultimate Defensive Rating of 110.0 points allowed / 100 possessions faced, which was second-best of anybody on our team playing more than 350 minutes, behind only Amir Johnson (.551 stop% @ 22.8% DPoss%, 109.5 DRat) and tied with Bosh (.545 stop% @ 19.5% DPoss%, 110.0 DRat). (All the team defensive numbers used to generate the DRat only come from the games in which the individual actually play.) Now, that's a far cry from being the hapless yutz that some want to present him as. To be sure, you would hope your center is better than that - and certainly facing more possessions. But it's far better than some want to portray.

Who was the worst on our team? Jose. He had a stop% of .376 @ 18.8% DPoss%, 118.3 DRat. To put that in some context, uncontested action (i.e. uncaused action, being guarded by thin air) had a stop% of .357 @ 7.9% DPoss%, 115.2 DRat. Further, when Jose missed time, the team became significantly better, to the tune of about 4 points / 100 possessions. When Andrea missed his two games (granted, a tiny sample size) the team actually played at around the same level defensively it normally did. Why didn't it get considerably better, if Andrea were the cause of the defensive badness by himself?

I think the answer is significantly more complex than "blame Andrea". I think the people who want to do that, unfortunately, are using guesswork generated by on/off court analysis from 82games.com instead of direct analysis. I suppose that's becasue there is a dearth of popularly published data for defensive metrics, and because many people struggle with defensive analysis. This tends to be expressed by assigning the vast majority of blame/credit for defensive performance to the big men, which I personally believe is an extremely naive view of defense. And then we have the blaming of Triano's defensive tactical beliefs for the team's defensive woes, which further is untenable.

I think the problems lay in having so many players (Andrea, Hedo, Jose) on the court who are at considerable disadvantage of speed and quickness, and consequently the team had absolutely no pressure on the basketball at any time. Pressure on the ball is the absolute foundation of your defense, and without it nothing you try will work.

EDIT: Another thing I forgot to mention...the on/off court data had considerable flux as the season fell apart for this team. Jose was somewhere around +12 points allowed/100 possessions after he got hurt, and that improved somewhat as he came off the bench. Andrea was a slight plus or a neutral factor for most of the year until the team totally collapsed after the All-Star break. This adds a lot of doubt to using on/off court data to explain cause, because the data did fluctuate so much. There's much better information to use that gives direct data, not indirect.

Hey Boris. Good to see you on the RealGM board.

I do know that you did track the games, but I do have some reservations with your method.

1. Not sure how many of you were tracking the numbers, but Synergy Sports, with all of its army of game trackers could not track all of the possessions, or did track them but could not assign blame or credit. So, I'm not sure how you alone, or with some friends, could be so definitive in your analysis.
2. I haven't checked PDSS in a long time, but I'm not sure it tracks absent/late help defence.
3. ON/OFF DRTG might not be the best indicator with small sample sizes, but I am using 4000+ minutes worth of data and even bigger number of possessions. And all point to one conclusion: the minute Bargnani steps on the floor, team defence goes to hell, by an 8+ points margin.

You have called the analysis facile, but I would like you to explain how
Bargnani + another big = 113 DRTG
Bosh + another big (not Bargnani) = 104 DRTG

Same teammates, same system, and with 4000+ minutes worth of data, about the same opposition.

We need to go out for a beer with Adam...

[Tony_Montana]

So it's a composite defensive stat that includes man and team defense? The Synergy Stats already showed that Bargnani is a decent man defender. The whole point of this thread is to showcase how awful we are as a team defending when Bargnani is playing.

[BorisDK1]

Hey Boris. Good to see you on the RealGM board.

I do know that you did track the games, but I do have some reservations with your method.

1. Not sure how many of you were tracking the numbers, but Synergy Sports, with all of its army of game trackers could not track all of the possessions, or did track them but could not assign blame or credit. So, I'm not sure how you alone, or with some friends, could be so definitive in your analysis.
2. ON/OFF DRTG might not be the best indicator with small sample sizes, but I am using 4000+ minutes worth of data and even bigger number of possessions. And all point to one conclusion: the minute Bargnani steps on the floor, team defence goes to hell, by an 8+ points margin.

You have called the analysis facile, but I would like you to explain how
Bargnani + another big = 113 DRTG
Bosh + another big (not Bargnani) = 104 DRTG

Same teammates, same system, and with 4000+ minutes worth of data, about the same opposition.

We need to go out for a beer with Adam...

I'd love to get together with Adam and you for a beer with Adam! Name the time, I'll make my place available. Adam's over here at least once per week anyway.

I think Synergy Sports may have been at a substantial disadvantage to yours truly. They had to look at every team in every game with only a finite staff working from video. I had one team to analyze (I didn't analyze opponents) and I had the benefit of 1) no deadlines, 2) PVR. It wasn't that hard. The team I'm coaching is using that method. And yes, sometimes blame or credit is tough to do (about 8% of the team's possessions couldn't be individually assigned this year), but it's not quite the Gordian Knot that I'm sure it's tempting to believe it is. And, not to sound conceited, but as a coach I've spenet a lot of time thinking and reading and working with various defensive situations. I feel fairly confident in my ability to analyze a variety of defensive scenarios.

As for on/off court data, it doesn't really tell you why something happens when somebody steps foot on or off. It doesn't communicate direct data. It communicates something and should be welcomed as such, but to try to explain all cause from it I do think is venturing into post hoc, ergo propter hoc fallacy. It certainlly communicates that Andrea certainly isn't making the defense good, but at the same time is he doing so directly or was he uniquely assigned to play with an imbalanced unit that focused entirely on offense in terms of skillset? On/off court data leaves you at a loss for the explanation. I feel pretty confident with a general analysis that Andrea won't make a defense good, but I think he's good enough at certain things to prevent us from saying that he's the primary cause of our problems.

Again, I also have to wonder why our defense didn't get that much better in the games where he didn't play at all? That's a predictable outcome if he were the cause of our badness, no? But our defense did look about average when Jose was hurt and not playing at all. I know that doesn't prove anything, but it's certainly an unexpected result if Andrea were so causal in our bad defense, I think you'd agree.

[BorisDK1]

So it's a composite defensive stat that includes man and team defense? The Synergy Stats already showed that Bargnani is a decent man defender. The whole point of this thread is to showcase how awful we are as a team defending when Bargnani is playing.

Project Defensive Score Sheet tabulates all individual defensive performance, as well as uncontested action. The team's performance is included into the final analysis in the DRat formula:

DRat = TeamDRat + %DPoss x (100 x (Opponent Points / Scoring Possession) x (1 - Stop%) - TeamDRat)

[dagger]

Man

Boris versus Supersub = The Stathead Cage Match

This is going to get interesting.

[supersub15]

Hey Boris. Good to see you on the RealGM board.

I do know that you did track the games, but I do have some reservations with your method.

1. Not sure how many of you were tracking the numbers, but Synergy Sports, with all of its army of game trackers could not track all of the possessions, or did track them but could not assign blame or credit. So, I'm not sure how you alone, or with some friends, could be so definitive in your analysis.
2. ON/OFF DRTG might not be the best indicator with small sample sizes, but I am using 4000+ minutes worth of data and even bigger number of possessions. And all point to one conclusion: the minute Bargnani steps on the floor, team defence goes to hell, by an 8+ points margin.

You have called the analysis facile, but I would like you to explain how
Bargnani + another big = 113 DRTG
Bosh + another big (not Bargnani) = 104 DRTG

Same teammates, same system, and with 4000+ minutes worth of data, about the same opposition.

We need to go out for a beer with Adam...

I'd love to get together with Adam and you for a beer with Adam! Name the time, I'll make my place available. Adam's over here at least once per week anyway.

I think Synergy Sports may have been at a substantial disadvantage to yours truly. They had to look at every team in every game with only a finite staff working from video. I had one team to analyze (I didn't analyze opponents) and I had the benefit of 1) no deadlines, 2) PVR. It wasn't that hard. The team I'm coaching is using that method. And yes, sometimes blame or credit is tough to do (about 8% of the team's possessions couldn't be individually assigned this year), but it's not quite the Gordian Knot that I'm sure it's tempting to believe it is. And, not to sound conceited, but as a coach I've spenet a lot of time thinking and reading and working with various defensive situations. I feel fairly confident in my ability to analyze a variety of defensive scenarios.

As for on/off court data, it doesn't really tell you why something happens when somebody steps foot on or off. It doesn't communicate direct data. It communicates something and should be welcomed as such, but to try to explain all cause from it I do think is venturing into post hoc, ergo propter hoc fallacy. It certainlly communicates that Andrea certainly isn't making the defense good, but at the same time is he doing so directly or was he uniquely assigned to play with an imbalanced unit that focused entirely on offense in terms of skillset? On/off court data leaves you at a loss for the explanation. I feel pretty confident with a general analysis that Andrea won't make a defense good, but I think he's good enough at certain things to prevent us from saying that he's the primary cause of our problems.

Again, I also have to wonder why our defense didn't get that much better in the games where he didn't play at all? That's a predictable outcome if he were the cause of our badness, no? But our defense did look about average when Jose was hurt and not playing at all. I know that doesn't prove anything, but it's certainly an unexpected result if Andrea were so causal in our bad defense, I think you'd agree.

Sure, for the beer, I'll email Adam when I am in the Burlington vicinity... Should be good!

I don't dispute that you've been diligent with your work, but I'll keep it as a reservation for now, because of eye (things can happen quickly, and as you said some of the possessions were not logged), prejudice, system (how do you know what Triano wants?), etc.

I'll bite on the Jose theory:
Team DRTG for the combo - Calderon / Bosh / another big (NO BARGNANI): 104.67
Team DRTG for the combo - Calderon / Bargnani / another big: 113.72

Your turn.

[ratul]

Our defense is awful, and our chemistry is not great with bargs - he might be better as a four but who knows - the fact is he and calderon are a liability on defense.

[Hendrix]

Hey, Welcome Boris D.

[Crazy-Canuck]

lol @ keeping that data for every game this season. do you mind posting yer game log spreadsheet?

You can download the final spreadsheet here in .pdf format. I don't have the spreadsheet available online yet, as it is a huge file with splits sorted in other workbooks. I'd be happy to post that this week sometime, if you'd like.

One caveat: there are editing mistakes in the team stats in the final page of the document, there, and haven't had a chance to correct them. I did post every single game's stats at raptorspace.com, if you have any doubts. My username there is BorisD.

Nice try with the "lol", though. lol @ u? I'm too old for the childish "pic or didn't happen" thing.

Welcome to the board and FYI, any stats that support Bargs do come with consequences here.

[andreafan]

Well calderon pulled his hammy so andrea won't have to cover his arse on defense for a while , nice.

[BorisDK1]

Sure, for the beer, I'll email Adam when I am in the Burlington vicinity... Should be good!

I don't dispute that you've been diligent with your work, but I'll keep it as a reservation for now, because of eye (things can happen quickly, and as you said some of the possessions were not logged), prejudice, system (how do you know what Triano wants?), etc.

I'll bite on the Jose theory:
Team DRTG for the combo - Calderon / Bosh / another big (NO BARGNANI): 104.67
Team DRTG for the combo - Calderon / Bargnani / another big: 113.72

Your turn.

I don't think the eye is any more jaundiced in my case then in the NBA's case with assists, rebounds or steals. It's a simple system: either you're guarding a guy or not, and in the outcome of a play you're either contributing to a stop or allowing a score in whatever way. It's not that hard to do.

When I said not every possession was tracked, I meant with Synergy, not with me. With my system, I got the outcome of every play this past season. I'm basing only on what I've heard, I'm not a subscriber and I'll certainly accept correction if necessary, but it sounds like Synergy is tracking outcome only of primary identifiable and trackable action (ball screens, post ups, dribble drives (?)). Are they tracking what's happening in transition? In ball reversal? In offensive rebounding? I get all that, you see. It's sometimes very difficult, in some offensive rebounding and transition, but I'm not giving ridiculously imbalanced results. I'm not tagging Jose for a FGA in a situation when he's still in the frontcourt when the opponents score on a 2-on-1, for instance. I hate his play, but not so much more than the rest of these softies that I'd go that far out of my way to blame everything on him.

How do I know what Jay wants? You watch enough Raptors basketball with that much attention to detail with a base knowledge of defensive tactics and it's not that hard. The Raptors played a very standard defense this year. The people decrying Jay's "system" IMO know nary a thing about basketball strategy and tactics. There's the occasional play that's just a complete mess-up where they're all completely out to lunch but far more often the issue was just plain poor execution. I think I'm well-versed enough to determine who was the principal cause of breakdown on a diagonal down-screen sequence, for example (something the Raptors could not stop to save their lives this year). It's not that hard to tell when a team is trying to jump-switch vs. contact-switch vs. lock-and-trail vs. jump over vs. jump under vs. just screw things up when you recognize these actions for what they are. It didn't even take me long to recognize that Jay ended up developing an entirely separate set of rules for Jose than for everybody else: switch all ball screens, switch all crossing action (except dribble handoffs), switch all screens when he's guarding a cutter. Nobody else had separate rules just for them. (Not that it did an iota of good.)

So, you're trying to pose the on/off court data (still) as explanatory for cause, but I still feel you're trying to use those data as 1) causal of team's bad defense and 2) judging solely one player at a time. I know you don't believe the latter because you've warned people against that, but I still think you're trying to use a metric which is merely an observation as to what happens as trying to explain why that happened, which I do not think is warranted.

But having said that, let's look at this:

Oct 28 - Dec 4 (Jose starting and healthy) Team DRat = 117.8
Dec 5 - Jan 3 (Games starting when Jose got hurt till the end of his injury) Team DRat = 106.4
Jan 6 - Mar 14 (Jose coming off bench) Team DRat = 112.9
Mar 17 - Apr 14 (Jose starting again) Team DRat = 113.4

Now, if you want to talk about a significant bloc of data, let's talk Dec 5 - Jan 3 when out of 821 minutes of game time and 1583 possessions, the team's defense suddenly improved by 11.4 points / 100 possessions. That's a big bloc of time, a good chunk of possessions. What are the odds that was a complete fluke?

Now, the 80 games in which Andrea played: Team DRat = 113.1
The 2 games he missed (Dec 9 and Jan 22, ironically both against Milwaukee): 115.1 (against a poor offensive team).

I think the on/off court method leaves way too many questions unanswered (against whom? who's responsible?). It indicates that Andrea is a defensive problem, and I would agree with that, but at the absolute worst I think he's a secondary cause of our problems. I'm not arguing he's a good defender, because he's not, but he's not egregiously bad in some regards either. I think the metrics when properly viewed show fairly conclusively that the only race for problem child defensively on this team is a race for second place next to Jose.

[Ripp]

I'm sorry to weigh in on such a controversial topic for my first post here, but I find much of the argumentation here overly facile. The people blindly insisting Bargnani's defense is somehow acceptable are oblivious to the fact that he just played over 2,800 minutes for what is the 21st worst defense in league history - well, since 1978 when we first had the requisite data, at any rate (measured by points allowed / 100 possessions worse than league average) so obviously he has to be lacking something.

I'm not sure I agree....it is possible to be a good defender on a bad defensive team. Or conversely, a bad defender on an elite defensive team. The question is, who is having what effect? Were the Magic an elite defensive team last year because of Hedo? Being able to quantify a bad defender on a good team and good defenders on bad teams is very useful, as the Hedo example indicates...

On the other hand, the discussion of primary cause of the defense from the OP and others is equally facile. I find using on/off court data as indicators of cause to be fallacious (post hoc, ergo propter hoc) and further, probably not using the best data available.

On some level, you are correct...we cannot be 100% sure from statistical data who is causing what. As you say, it would technically be a fallacy to look at +/- data or box scores, or in fact ANY sort of statistics to prove that for example LeBron was the reason the Cavs were an elite offensive team. Or Dwight causing the Magic an elite defensive team. Nevertheless, we will still look at the data and make decisions based on it.

I believe the best data available is through a method called Project Defensive Score Sheet (spelled out in Dean Oliver's Basketball on Paper), in which all the stops produced and scores allowed are tabulated for all the players (and uncontested action as well) and the individual Defensive Rating generated from that is the best way of generating defensive metrics. That data is not currently kept in boxscores by the NBA, so that data has to be kept manually. I did that for this past year - every single possession, all 82 games.

So can you outline his methodology, describe it? Some methodologies make sense, others do not (by "make sense" I mean accurately gauging who is doing a good job on defense and who is not.)

This past year, Bargnani played ~ 2800 minutes. In those minutes, he forced 553.5 missed field goal attempts (not including blocks), 75.5 turnovers (not including steals) and 64 missed free throws, to go along with his 389 defensive rebounds, 111 blocks and 25 steals. He allowed 404 field goals and 188 made free throws to go along with those. That translates to a stop% of .552 while facing 19.2% of the opponents' possessions defensively, giving him an ultimate Defensive Rating of 110.0 points allowed / 100 possessions faced, which was second-best of anybody on our team playing more than 350 minutes, behind only Amir Johnson (.551 stop% @ 22.8% DPoss%, 109.5 DRat) and tied with Bosh (.545 stop% @ 19.5% DPoss%, 110.0 DRat). (All the team defensive numbers used to generate the DRat only come from the games in which the individual actually play.) Now, that's a far cry from being the hapless yutz that some want to present him as. To be sure, you would hope your center is better than that - and certainly facing more possessions. But it's far better than some want to portray.

So this Stop% stuff sounds kooky to me. Again, it would be helpful if you could explain the methodology so we can understand how it works. However, I do like tracking defensive results, Synergy style. I'd be really happy if you published that sort of stuff on Google docs.

BTW, just to reveal my own biases...I'm pretty pro APM and its variants. Statistical Plus/Minus is a pretty useful tool, and I've worked on some variants of it myself that I think are even better. That is sort of the right direction for analyzing players...using both +/- data and box scores. Honestly, I wish synnergy could publish a sort of expanded end-of-season box score for players that included defensive variables. That I think would be extremely useful.

[BorisDK1]

I'm not sure I agree....it is possible to be a good defender on a bad defensive team. Or conversely, a bad defender on an elite defensive team. The question is, who is having what effect? Were the Magic an elite defensive team last year because of Hedo? Being able to quantify a bad defender on a good team and good defenders on bad teams is very useful, as the Hedo example indicates...

Playing that many minutes on a historically bad team has to raise some serious questions. There are types of defenders - Joe Dumars, for example, who defended very well but who did not produce a lot of defensive statistics - who have played on both great and bad defensive teams. Is Andrea in that category? I'd say no.

On some level, you are correct...we cannot be 100% sure from statistical data who is causing what. As you say, it would technically be a fallacy to look at +/- data or box scores, or in fact ANY sort of statistics to prove that for example LeBron was the reason the Cavs were an elite offensive team. Or Dwight causing the Magic an elite defensive team. Nevertheless, we will still look at the data and make decisions based on it.

That was a comment specifically on the on/off court data, and trying to use it to establish cause.

So can you outline his methodology, describe it? Some methodologies make sense, others do not (by "make sense" I mean accurately gauging who is doing a good job on defense and who is not.)

It tracks who produces what defensively by not only the blocks, steals and defensive rebounds we already have, but by tracking:

Forced misses: A player is guarding a player, who shoots and misses from the floor. That is a forced miss. Credit can be shared between teammates (player gets beat on the dribble, but stays in the play and helping teammate forces a missed attempt. They both get .5 FM). Blocked shots are separate.
Field goals allowed: same deal, except the try goes in.
Forced turnover: a player is guarding another player, who turns the ball over (not including steals). A forced turnover is credited to that player.
Forced free throw: a player fouls an opponent, who makes the resulting free throw(s). These are forced free throws.
Forced free throws missed: same deal, except free throws are missed.

There are some peculiarities for special situations, but suffice it to say uncontested action is attributed to category "team", not an individual player.

So this Stop% stuff sounds kooky to me. Again, it would be helpful if you could explain the methodology so we can understand how it works. However, I do like tracking defensive results, Synergy style. I'd be really happy if you published that sort of stuff on Google docs.

Meaning, "it sounds new to me".

Stop% = Total stops / Total individual defensive possessions.

You can read more on this method in Google Books, just look up "Dean Oliver Basketball on Paper".

BTW, just to reveal my own biases...I'm pretty pro APM and its variants. Statistical Plus/Minus is a pretty useful tool, and I've worked on some variants of it myself that I think are even better. That is sort of the right direction for analyzing players...using both +/- data and box scores. Honestly, I wish synnergy could publish a sort of expanded end-of-season box score for players that included defensive variables. That I think would be extremely useful.

I have very little use for these magical one-number metrics (APM, SPM, aSPM, PER, etc.).

I have done what Synnergy could do - except more accurately, and involving more than direct action.

[Ripp]

Oh, I forgot to say..welcome BorisDK1! Always nice to have other voices here, especially when they can reason and think. Helps to counter the usual large number of...people...that feel obliged to post and comment on things they don't understand (I'm looking at you, ZefSyde.)