Rondo vs the other elite PGs: by the numbers

[drza44]

 The article says:
__________________________________________________________________________________

  This means that the range of defensive impacts will be much wider for interior players than perimeter plays. The difference between a good and bad defensive point guard won’t be nearly as pronounced as the difference between a good and bad defensive center. Using a simple mathematical example, imagine the following:

    * A “Bad” Defender allows 50% eFG shooting
    * A “Good” Defender allows 40%e FG shooting

Assume free throw accuracy is a constant (the league average). Based on these shooting percentages, at the center position the difference between our bad defender and good defender is 2.9 pts/100 (a difference in efficiency this year between an average team and the 8th-best team). But at PG, the difference between our good and bad defenders shrinks to 1.2 pts/100.
_______________________________________________________________________________

  I agree with all of this. But consider Rondo in particular. He gets about 2 steals per 100 possessions more than the average guard, 3 more than a bad defender. If you include turnovers forced the gulf is probably wider. That would push his impact on the game at least into the same range as the impact difference between a good and bad defensive center.  

You respond here to a point I was making with Guava Wrench, but I'm curious as to your response to my last post to you in which I tried to cut out the side discussions (of which the big vs small defense, though applicable in theory, has become) and focus this on Rondo's offensive and defensive impacts specifically against the Nashes of the world.

Regardless of how he may or may not stack up to other bigs, Rondo's defensive APM according to multiple multi-year studies (which lowers the noise and also focuses on team impact) is great for a point guard, but ultimately less than 1/4 as large as Nash's offensive impact.  This year's numbers suggest strongly that Nash's offensive impact and Rondo's defensive impact this year are very much in-tune with where they were in those multi-year studies.  And each of the 5 different measures examined in this OP (both individually and taken as a group) argue that Nash's overall production/impact have been larger than Rondo's overall production/impact this year.

Outside of the conclusion not fitting with your beliefs, are there any direct issues you have with my methodology that I haven't addressed in our discussions?  This thread was never meant to denigrate Rondo, more as a way to try to objectively quantify his production this season vs various other top PGs with tools that aren't always readily obvious/used (I plan to make similar posts comparing Ray and Pierce vs the other wings, and KG vs the better bigs of the league).  And frankly, the tools do support the opinion I'd have had just from watching without any numbers at all...namely that Rondo is one of the best PGs in the league.  I guess for me, I just don't see the shame in Rondo maybe being clearly behind 2 super-elite point guards and part of a handful of others all with a legitimate case as the 3rd best PG in the league so far this year.  If anything, if Rondo measures out that well in advanced stats despite his unconventional approach, it's actually a compliment to him and an indication that the advanced numbers really can capture some of the things we might believe through observation that aren't so easy to describe based on highlights and basic box scores. 

[BballTim]

  Ok, it was late. I meant that you said that point guard was the least important position defensively, which I don't think is the case. BTW, I checked Rondo and Perk's on/off stats for the prior 3 seasons, and the difference was about .5 points per 100 possessions. Again, those numbers don't take things into account like lineups and opponents.

I'd just like to note that, when gathering your stats, you claimed that you don't like adjusted plus/minus because it's too noisy. You're basing this argument on *unadjusted* numbers.

Somewhat true, but that's only in the halfcourt setting. The Celts are always a top team in transition defense and forcing turnovers. Those are important to defensive efficiency, and I'd argue that Rondo's more responsible for those areas than the bigs are.

I'm grouping these together to respond to because I fear that in our growing discussion we could lose sight of the main point where we initially disagreed, namely whether Rondo's defense is enough to bridge the gap for a player like Nash's offensive advantage over him.  As you point out, our discussion was devolving a bit more into generalities and unadjusted numbers to make more encompassing points when we have specific numbers we could look at.

Re: +/- stats.  Yes, adjusted +/- for a given year is very noisy.  But over time things get a lot less noisy, and the story comes out.  I found a 5-year APM calculation on the APBRmetrics board (2005 - 2010), and there's another 6 year APM calculation publicly available (2003 - 2009, https://spreadsheets.google.com/ccc?key=0AnGzTFTtSPx_dE9xcTVITjhRSDdfRkJ5MHJ2cU1nb0E&hl=en#gid=0 ) that each help get the point across for these specific players.

For both APMs, Nash measures out with by-far the biggest offensive adjusted +/- at any position in the NBA (+8.05 in the 5-year study, +8.84 in the 6-year study).  On the flip-side, Rondo's defensive APM in both studies was about +2, and in both cases he was right around the best measured PG in the league and ranked in the 50 - 70 range in the NBA overall on defense. 

I didn't include these types of multi-year comparisons in the OP because we're looking specifically at this year, but from the 2 +/- based stats I did include in the OP it's pretty clear that the same trend would show up this year as well.  Nash's offensive impact is much larger than anything Rondo could do defensively, and in fact even if you look at the sum impact that includes both offense and defense Nash measures out higher.  Which has been my point all along, though sometimes that can get a bit hidden in the analogies and generalizations as I tried to think of better ways to emphasize that.

  Again, though, you're finding different ways to measure individual output on offense, but you're by and large ignoring the impact of the player on the TEAM. On defense, you're arguing the opposite. You're skewing your arguments to lower Rondo's value, even if it's not your int ention. For instance, in the 11 games when Rondo was out Ray shot about 35% on threes, but he's hitting about 50% of them when Rondo plays. Which of your stats accounts for that? 

Both the adjusted +/- stat I included and the Roland rating that is based in part of net +/- should account for that.  Both of those stats consider the impact of the p layer on the team offense...in fact, they're the same stats that also help account for the player's impact on team defense.  In fact, I'm a bit confused now as to where you're coming from with this particular rebuttal point...how could I be using the same +/- based stats to argue in opposite ways for team defense and offense?  The conclusions might change based on what the stat tells us, but the methodology for the analysis is the same.

  Our original disagreement was your claim that point guard was the least important defensive position. I don't think that's true. Rondo doesn't have the plus/minus numbers of a Nash because he's not on a team that's built around his strengths. In terms of Rondo's impact on the Celts, I'd say that, based on observation, it's at least as great as the impact of KG, a top defensive big that's 22nd in the league in PER. The team was at least as good without KG as it was without Rondo.

[Fafnir]

Adjusted plus/minus and our efficiency differential for the games KG/Rondo missed indicate that losing KG cost us more.

The Celtics have a couple of players that can fill in for Rondo's offensive role. BBD's play as a starter falls so far below KG's that we can't make it up.

[drza44]

  Our original disagreement was your claim that point guard was the least important defensive position. I don't think that's true. Rondo doesn't have the plus/minus numbers of a Nash because he's not on a team that's built around his strengths. In terms of Rondo's impact on the Celts, I'd say that, based on observation, it's at least as great as the impact of KG, a top defensive big that's 22nd in the league in PER. The team was at least as good without KG as it was without Rondo.

I initially started on the point-guard-not-as-important-defensively kick in response to the idea that Rondo's defense was enough to overcome Nash's offensive advantages.  Because that discussion was on-going with you I assumed it started with you as well, but if not I apologize.

But my point still stands, that Rondo's defensive impact vs other bigs is only relevant in this thread as a reflection of what that means in his comparison to other PGs.  That said, the links I posted previously just as easily support the notion that Rondo's defense just can't compare with the best bigs.  In the same multi-year defensive +/- studies I referenced before, Rondo's defensive APM was roughly 1/4 to 1/2 of the defensive APMs of the best bigs of the last several years.  Again, Rondo was right around the best PG defensively but he was in the 50 - 70 range overall in defensive +/-.  And these are bigs from a bunch of different teams, so it can't just be a system argument.  In his own system, Rondo's defensive APM is MUCH lower than the best big on his team.

It's not a controversial notion that big men are more important to a defense than guards as a general rule, and generally the impact stat difference between them isn't small.  I'm not really planning to put much more into this particular line of debate in this thread (as I said, I prefer to keep it more about the PGs if possible) but I really don't see how bigs being more important on defense is really worth much argument anyway.

[BballTim]

 The article says:
__________________________________________________________________________________

  This means that the range of defensive impacts will be much wider for interior players than perimeter plays. The difference between a good and bad defensive point guard won’t be nearly as pronounced as the difference between a good and bad defensive center. Using a simple mathematical example, imagine the following:

    * A “Bad” Defender allows 50% eFG shooting
    * A “Good” Defender allows 40%e FG shooting

Assume free throw accuracy is a constant (the league average). Based on these shooting percentages, at the center position the difference between our bad defender and good defender is 2.9 pts/100 (a difference in efficiency this year between an average team and the 8th-best team). But at PG, the difference between our good and bad defenders shrinks to 1.2 pts/100.
_______________________________________________________________________________

  I agree with all of this. But consider Rondo in particular. He gets about 2 steals per 100 possessions more than the average guard, 3 more than a bad defender. If you include turnovers forced the gulf is probably wider. That would push his impact on the game at least into the same range as the impact difference between a good and bad defensive center.  

You respond here to a point I was making with Guava Wrench, but I'm curious as to your response to my last post to you in which I tried to cut out the side discussions (of which the big vs small defense, though applicable in theory, has become) and focus this on Rondo's offensive and defensive impacts specifically against the Nashes of the world.

  The fact that I was responding to a point you were making to someone else doesn't mean my point was wrong. As for Rondo's impact, as I noted elsewhere, it's roughly the same as KG, who's an elite defender/rebounder and a pretty good offensive player. I'd say Nash is likely having a better year than Rondo but a lot of that's due to Rondo's lack of health. I certainly wouldn't have said Nash was playing as well as Rondo before the foot/hamstring injuries hit. While Nash is probably a better offensive player than Rondo I think if you put him on the Celts his impact on the offense would be much less than what it is on the Suns. Likewise, putting Rondo on the Suns would greatly increase Rondo's impact.

[BballTim]

Adjusted plus/minus and our efficiency differential for the games KG/Rondo missed indicate that losing KG cost us more.

The Celtics have a couple of players that can fill in for Rondo's offensive role. BBD's play as a starter falls so far below KG's that we can't make it up.

  We had at least as good a record without KG as we had without Rondo and we beat the team with the best record in the league without KG. We played stronger teams in general.

[LB3533]

IMO, the most important defender within any defensive scheme is the defender closest to the point of attack.

That means, if the offensive PG has the ball then the defender of that PG is the most important defender.

Rondo will be the most important defender against the premiere elite PG's in this league because those PG's will have the ball in their hands the majority of the game.

If Rondo can keep himself infront of those PGs and cut off the point of attack, that would prove huge to our defense, and indirectly our defensive rebounding %.

[drza44]

 The fact that I was responding to a point you were making to someone else doesn't mean my point was wrong. As for Rondo's impact, as I noted elsewhere, it's roughly the same as KG, who's an elite defender/rebounder and a pretty good offensive player. I'd say Nash is likely having a better year than Rondo but a lot of that's due to Rondo's lack of health. I certainly wouldn't have said Nash was playing as well as Rondo before the foot/hamstring injuries hit. While Nash is probably a better offensive player than Rondo I think if you put him on the Celts his impact on the offense would be much less than what it is on the Suns. Likewise, putting Rondo on the Suns would greatly increase Rondo's impact.

You're losing me a bit here.  If you're talking about Rondo vs KG overall, it's completely irrelevant to the thread so I'm not sure where you're going with it.  If you're talking about Rondo vs KG defensively, then you're just wrong.  Rondo's defensive impact isn't remotely as large as KG's no matter how you measure it. 

As far as Rondo vs Nash, you threw a lot of random things into that paragraph.  If your argument is that Nash's numbers are better than Rondo's because Rondo is injured, that's outside of the scope of what you can get from the stats I cited.  All the numbers can demonstrate is what actually has happened, which includes Rondo's injury.  They can't argue over whether Rondo has more potential when healthy.

As to your last sentences, that if you swapped Nash and Rondo their impacts would switch...that's an example of something that would seem to require some type of support.  Nash this year has produced more, more efficiently, with a larger measured impact thus far than Rondo.  Your hypothetical swap situation could be worth discussing, but in the face of the amount of info that is in the thread I'd think more than just an opinion statement would be needed to make a strong argument.

[BballTim]

 The fact that I was responding to a point you were making to someone else doesn't mean my point was wrong. As for Rondo's impact, as I noted elsewhere, it's roughly the same as KG, who's an elite defender/rebounder and a pretty good offensive player. I'd say Nash is likely having a better year than Rondo but a lot of that's due to Rondo's lack of health. I certainly wouldn't have said Nash was playing as well as Rondo before the foot/hamstring injuries hit. While Nash is probably a better offensive player than Rondo I think if you put him on the Celts his impact on the offense would be much less than what it is on the Suns. Likewise, putting Rondo on the Suns would greatly increase Rondo's impact.

You're losing me a bit here.  If you're talking about Rondo vs KG overall, it's completely irrelevant to the thread so I'm not sure where you're going with it.  If you're talking about Rondo vs KG defensively, then you're just wrong.  Rondo's defensive impact isn't remotely as large as KG's no matter how you measure it. 

As far as Rondo vs Nash, you threw a lot of random things into that paragraph.  If your argument is that Nash's numbers are better than Rondo's because Rondo is injured, that's outside of the scope of what you can get from the stats I cited.  All the numbers can demonstrate is what actually has happened, which includes Rondo's injury.  They can't argue over whether Rondo has more potential when healthy.

As to your last sentences, that if you swapped Nash and Rondo their impacts would switch...that's an example of something that would seem to require some type of support.  Nash this year has produced more, more efficiently, with a larger measured impact thus far than Rondo.  Your hypothetical swap situation could be worth discussing, but in the face of the amount of info that is in the thread I'd think more than just an opinion statement would be needed to make a strong argument.

  Rondo vs Nash wasn't really my point. More Rondo vs players like Rose/Westbrook, who I don't think are really in Rondo's category.

[ElGee]

Doc claims the PG pressure is extremely important to the defense so that a lot of time is taken off the shot clock before the other team gets into their offense.

In other words, the PG could mean 5 or 6 less seconds of playing defense per possession for teammates. This also means more bad shots by opposing teams and less defensive breakdowns.

While this does not in itself mean that Rondo is necessarily a defensive lynch pin, it does point to the potential high impact of the PG.

Add to that the amount of time that the opposing PG has the ball and needs to be defended and pressured to disrupt the offense and the prevalence of pick and roll plays w/ PGs and I question why PGs should be any less significant than other players on defense.

1) Her's a link to an article from a guy that tracked every possession of every game in the 2010 postseason while looking for what he calls "defensive usage".  http://elgee35.wordpress.com/2011/01/22/defensive-usage/ The key take-home from the article is that about 14% of possessions ended in turnovers, about 30% ended in fast break attempts or intentional fouls (end of games) or things like that, and about 56% ended in contested shot attempts/FTs.  Of those contested shots, point guards were defending on about half as many shots (13%) as PFs (24%) or centers (31%).  The big guys, because they help at the rim, are just in on trying to prevent a lot more shots than the perimeter guys are.  Now, the article isn't perfect and I'm not endorsing this as another definite stat, I'm merely using his findings to point out that the intution is true: big guys face a lot more shots, and also a lot more high-percentage shots than little guys do, which is why in general big guys are a lot more important to a team's defense than little guys.

  The article says:
__________________________________________________________________________________

  This means that the range of defensive impacts will be much wider for interior players than perimeter plays. The difference between a good and bad defensive point guard won’t be nearly as pronounced as the difference between a good and bad defensive center. Using a simple mathematical example, imagine the following:

    * A “Bad” Defender allows 50% eFG shooting
    * A “Good” Defender allows 40%e FG shooting

Assume free throw accuracy is a constant (the league average). Based on these shooting percentages, at the center position the difference between our bad defender and good defender is 2.9 pts/100 (a difference in efficiency this year between an average team and the 8th-best team). But at PG, the difference between our good and bad defenders shrinks to 1.2 pts/100.
_______________________________________________________________________________

  I agree with all of this. But consider Rondo in particular. He gets about 2 steals per 100 possessions more than the average guard, 3 more than a bad defender. If you include turnovers forced the gulf is probably wider. That would push his impact on the game at least into the same range as the impact difference between a good and bad defensive center.
  

A few things:
(1) Rondo's DUsg using this methodology was low in the playoffs last year. Around 6% I think. One can add in steals and it still doesn't change much.
(2) I have a new iteration of DUsg this year involving errors and turnovers and his is higher in the 6 or 7 games I've tracked.
(3) The most difficult defensive contribution to track is "keeping the PG in front of you."  Rondo does that well. But he also is burned a lot going for steals.
(4) I have Rondo consistently scoring out as a very good defender. Probably a touch overrated, but very good.

[BballTim]

Doc claims the PG pressure is extremely important to the defense so that a lot of time is taken off the shot clock before the other team gets into their offense.

In other words, the PG could mean 5 or 6 less seconds of playing defense per possession for teammates. This also means more bad shots by opposing teams and less defensive breakdowns.

While this does not in itself mean that Rondo is necessarily a defensive lynch pin, it does point to the potential high impact of the PG.

Add to that the amount of time that the opposing PG has the ball and needs to be defended and pressured to disrupt the offense and the prevalence of pick and roll plays w/ PGs and I question why PGs should be any less significant than other players on defense.

1) Her's a link to an article from a guy that tracked every possession of every game in the 2010 postseason while looking for what he calls "defensive usage".  http://elgee35.wordpress.com/2011/01/22/defensive-usage/ The key take-home from the article is that about 14% of possessions ended in turnovers, about 30% ended in fast break attempts or intentional fouls (end of games) or things like that, and about 56% ended in contested shot attempts/FTs.  Of those contested shots, point guards were defending on about half as many shots (13%) as PFs (24%) or centers (31%).  The big guys, because they help at the rim, are just in on trying to prevent a lot more shots than the perimeter guys are.  Now, the article isn't perfect and I'm not endorsing this as another definite stat, I'm merely using his findings to point out that the intution is true: big guys face a lot more shots, and also a lot more high-percentage shots than little guys do, which is why in general big guys are a lot more important to a team's defense than little guys.

  The article says:
__________________________________________________________________________________

  This means that the range of defensive impacts will be much wider for interior players than perimeter plays. The difference between a good and bad defensive point guard won’t be nearly as pronounced as the difference between a good and bad defensive center. Using a simple mathematical example, imagine the following:

    * A “Bad” Defender allows 50% eFG shooting
    * A “Good” Defender allows 40%e FG shooting

Assume free throw accuracy is a constant (the league average). Based on these shooting percentages, at the center position the difference between our bad defender and good defender is 2.9 pts/100 (a difference in efficiency this year between an average team and the 8th-best team). But at PG, the difference between our good and bad defenders shrinks to 1.2 pts/100.
_______________________________________________________________________________

  I agree with all of this. But consider Rondo in particular. He gets about 2 steals per 100 possessions more than the average guard, 3 more than a bad defender. If you include turnovers forced the gulf is probably wider. That would push his impact on the game at least into the same range as the impact difference between a good and bad defensive center.
  

A few things:
(1) Rondo's DUsg using this methodology was low in the playoffs last year. Around 6% I think. One can add in steals and it still doesn't change much.
(2) I have a new iteration of DUsg this year involving errors and turnovers and his is higher in the 6 or 7 games I've tracked.
(3) The most difficult defensive contribution to track is "keeping the PG in front of you."  Rondo does that well. But he also is burned a lot going for steals.
(4) I have Rondo consistently scoring out as a very good defender. Probably a touch overrated, but very good.

  1) By and large Rondo shut down opposing pgs last year in the playoffs. That would lower his usage. OTOH, I can remember watching a Heat game where you could hear their coaches discuss how they were having trouble just getting the ball into the frontcourt against Rondo. Where would that fit in to any metrics?

  2) Early in the season when Rondo was healthier his defense was great. He's getting back to that level IMO.

  3) Rondo does go for steals some of the time but a lot of the time he goes for steals when people get past him as opposed to people getting past him because he goes for the steal.

  4) Overrated in general, or overrated compared to other pgs? BTW, I think Rondo causes a decent amount of turnovers that don't result in steals, such as poking the ball away from players and having it go OOB off of them. Do you measure that?

[ElGee]

Yes, I track those events too. Rondo had 7 in last year's playoffs, 52nd in the playoffs (of 133 qualifiers) per possession at doing this.

[drza44]

Yes, I track those events too. Rondo had 7 in last year's playoffs, 52nd in the playoffs (of 133 qualifiers) per possession at doing this.

ElGee, how'd you you even know someone from here had referenced your blog?  You got some kind of esp or something, lol?

[BballTim]

Yes, I track those events too. Rondo had 7 in last year's playoffs, 52nd in the playoffs (of 133 qualifiers) per possession at doing this.

ElGee, how'd you you even know someone from here had referenced your blog?  You got some kind of esp or something, lol?

  He's a real poster? I was leaning towards sock puppet...

[drza44]

Yes, I track those events too. Rondo had 7 in last year's playoffs, 52nd in the playoffs (of 133 qualifiers) per possession at doing this.

ElGee, how'd you you even know someone from here had referenced your blog?  You got some kind of esp or something, lol?

  He's a real poster? I was leaning towards sock puppet...

Lol.  He's over on the RealGM player comparison and stats boards all the time, and he's got a basketball blog called "Back Picks" he's running these days.  I just never expected to "see" him in this thread...