Charles
Joined: 16 May 2005
Posts: 134
PostPosted: Fri Oct 26, 2007 3:39 pm Post subject: Are top-rated point guards under-rated by PER? Reply with quote
First of all, there is no question that summary stats like PER have value. They are easy to read, incite discussion among fans and help promote the game. They also have some use on the analytical side, where they can be helpful in tracking an individual's career development. Suppose a player's scoring drops three points a game, but his offensive rebounding and scoring efficiency increase. Is he still as valuable to the team, or has he begun to decline? In providing a rough summation of a player's contributions, PER offers a reasonable starting point for answering this kind of question.
However, when it comes to comparing players - especially, players with different roles - this type of stat can be very misleading. After all, it's possible that a logic based system might do a solid job of comparing the value of free throw to that of a field goal or even estimating the value of an isolated event like a steal. But, how do you "logic out" the value of an individual defensive rebound or an assist? You can't. Those kinds of questions require more than logic; they require research.
This is the problem. Although, a rational stat like PER might appear to be scientific, the best it can really do is mimic the opinions of its author. Those opinions may be well informed and the formula may be well thought out. But, concrete answers require empirical evidence.
-----------------------------------
Okay, are point guards under-rated by PER? I think they are ridiculously under-rated.
Let's start with the basic: how much is an assist worth? For each assisted field goal PER assigns one-third of the credit to the assister and two-thirds of the credit to the scorer. The rationale behind this is that the play maker has done one thing (pass), while the finisher has done two things (get open and make the basket.)
But, is that a reasonable basis upon which to assign weights?
Dwyane Wade drives through the paint and begins his upward trajectory to the rim enticing both his own defender and the weak side help to leave their feet. Then, at the last instant, Wade flips the ball behind his back to Udonis Haslem for a quick little, jack-knife slam. Wade is credited with an AST, Haslem with a FGM and the PER translation is one-third credit to Wade, two-thirds credit to Haslem. But, Wade has utilized a rare talent, while Haslem has simply completed a play that should be routine for any competent NBAer. Wade clearly deserves more of the credit in this sequence.
To Hollinger's credit, he acknowledges this as a problem in the introduction to PER. Unfortunately, rather than dealing with the issue empirically, he defends the weights by stating that "point guards are not under-represented among the top-rated players." Well, if there is evidence to that affect, perhaps it would be a defense, but (as far as I know) no evidence is offered. It seems as if the "galvanizing" evidence is simply that PER succeeds in echoing Hollinger's opinion on the value of point guards.
Now, checking your output against expert opinion is certainly worthwhile. But, rather than just rely on just the author's opinion, let's see how PER's assessment of top-rated point guards stacks up beside some objective expert opinion.
Ten point guards made the Hall of Fame's "NBA's 50 Greatest Players" list. Here they are along with their best single season PER (pre-1988 PERs are taken from the estimates at
http://www.basketball-reference.com/about/per.html.)
Code:
Player MaxOfPER
Nate Archibald 25.2
Dave Bing 22.5
Bob Cousy 21.6
Walt Frazier 21.6
Magic Johnson 27.0
Earl Monroe 19.3
Oscar Robertson 27.6
John Stockton 23.9
Isiah Thomas 22.2
Lenny Wilkens 20.3
The base PER is 15.0, so those are fairly high numbers. But, considering that the season best PER over the past twenty years has averaged 29.8, are they high enough? Here is where each HOF point guard's best season ranks among the best PER seasons of all players at all positions.
Code:
Player Rank of best single season PER
Nate Archibald 137th
Dave Bing 378th
Bob Cousy 492nd
Walt Frazier 504th
Magic Johnson 65th
Earl Monroe 1,038th
Oscar Robertson 55th
John Stockton 222nd
Isiah Thomas 404th
Lenny Wilkens 753rd
And, here are some newer additions based on ESPN.com "10 greatest point guards of all time."
Code:
Jason Kidd 375th
Steve Nash 228th
Gary Payton 252nd
I'm not a fan of the "smell test", but that seems to be the basis of validation for logic based, summary stats, so let's check the aroma from PER's ratings of elite point guard.
1. McGrady, Wade (twice), Nowitzki (twice), Kobe and LeBron have all registered PERs at least one to three points higher than any of Magic Johnson's MVP seasons. Magic Johnson. Magic.... Johnson.
After Magic and Oscar - who get a lot of PER for being the two top rebounding point guards of all-time - things get really hairy (btw, according to B-R.com the top five rpg guards (no G-Fs) of all time are... Oscar, Magic, JKidd, Fat Lever and Walt Frazier... all point guards. Oscar and Magic both averaged better than one rebound a game more than MJ or Clyde Drexler.) All right, continuing...
2. Amare Stoudemire and Elton Brand both have PERs which rank among the top one hundred of all time, while John Stockton can't crack the top two hundred... Isiah Thomas and Clyde Frazier can't even crack the top four hundred. You might convince me that Karl Malone should rank ahead of John Stockton, but PER is telling me that Elton Brand (26.5) is a much more valuable player than John Stockton (23.9) or Isiah (22.2). Really?
3. Bob Cousy's best PER was 21.6 placing him in a tie for 492nd place with, among others, -- Larry Hughes. Yes, the same Bob Cousy who was MVP and made first team All-NBA ten consecutive seasons. Let's see Cousy or Hughes? Hughes or Cousy...? Well, at least Cous gets more respect than "50 Greatest of All-time" teammate Earl Monroe. Earl the Pearl's best PER weighs in at one thousand and thirty eighth -- same spot as Ruben Patterson and Matt Harpring.
If PER does not under-rate elite point guards then the history of the NBA needs a serious re-write.
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bchaikin
Joined: 27 Jan 2005
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Location: cleveland, ohio
PostPosted: Fri Oct 26, 2007 5:03 pm Post subject: Reply with quote
Bob Cousy's best PER was 21.6 placing him in a tie for 492nd place...
i'm certainly not saying bob cousy was not a great basketball player - he was. but if you are looking for a statistical reason as to why he doesn't rate higher in a statistically based rating system, one key reason would be his shooting. looking at his best 10 year stretch, say 1951-52 to 1960-61, his FG% was .373 when the league average was .388, and his ScFG% (overall shooting) was .441 when the league average was .444....
during those 10 years he scored 19.7 pts/g, and if you look at the 20 players who averaged at least 17 pts/g during this same time period, cousy had the worst FG% and worst ScFG%...
on the other hand, a PG like john stockton for example, although not the scorer cousy was, did score 15.6 pts/g during his best 10 year stretch, but shot overall a ScFG% that was 8% better than the league average...
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Conan the Librarian
Joined: 03 Sep 2007
Posts: 35
PostPosted: Fri Oct 26, 2007 6:27 pm Post subject: Reply with quote
The issue of shooting % raises another interesting question about stats like PER as they relate to point guard. PG's, more so than any other position, are likely to take lower % shots with the clock winding down, simply by virtue of handling the ball more. This is not universally true, and I'm not sure how big an impact it would have on shooting %, but it certainly does have an impact. Are PG's to be punished for taking the only available shot late in the clock, even if it is a bad one, rather than risk a 24-second violation and a turnover?
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Chronz1
Joined: 22 May 2006
Posts: 201
PostPosted: Fri Oct 26, 2007 9:35 pm Post subject: Reply with quote
Ive always agreed with what you mentioned about dishing, there is no stat that is more opinionated than the assist as some are clearly worth more than others. I like to give both players equal credit but I know there are cases when the shooter did more of the work and the creator did more.
So yea PER does seemingly underrate PG's but much of what they do is intangible, they are looked upon as leaders but does it really end only at PG's? What about players who rack up alot of assist but are also scorers. Say Joe Johnson vs Michael Redd. JJ is obviously not the scorer Redd is but hes more of an all around threat. Personally I think Redd is the better player I just find it odd that his PER is that much higher than JJ's.
Im curious as to how much better PG's would be rated if they were given 2/3 the credit.
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Mountain
Joined: 13 Mar 2007
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PostPosted: Fri Oct 26, 2007 10:18 pm Post subject: Reply with quote
PER formula tends to place scorers high and that may disadvantage pass first or traditional PGs especially those from much earlier eras.
Career PER list for PGs depends on filter, using 20,000+ minutes I see the rank order of Magic, Robertson, Stockton... Iverson, K Johnson, Nash, Cassell, Brandon Cousy,
Price, Marbury, Frazier, Kidd, Payton. Hardaway, Billups, Francis, I Thomas, Rod Strickland Archibald Lever, Terry, Bing, A Hardaway, Porter, Monroe Bibby Wilkens, etc.
Last edited by Mountain on Sat Oct 27, 2007 3:56 pm; edited 1 time in total
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Charles
Joined: 16 May 2005
Posts: 134
PostPosted: Fri Oct 26, 2007 11:39 pm Post subject: Reply with quote
bchaikin wrote:
Bob Cousy's best PER was 21.6 placing him in a tie for 492nd place...
i'm certainly not saying bob cousy was not a great basketball player - he was. but if you are looking for a statistical reason as to why he doesn't rate higher in a statistically based rating system, one key reason would be his shooting. looking at his best 10 year stretch, say 1951-52 to 1960-61, his FG% was .373 when the league average was .388, and his ScFG% (overall shooting) was .441 when the league average was .444....
during those 10 years he scored 19.7 pts/g, and if you look at the 20 players who averaged at least 17 pts/g during this same time period, cousy had the worst FG% and worst ScFG%...
True. However, very few of those scorers were guards. And the problem is that while Cousy's best PER of 21.6 stacks up well against other point guards, it stacks up poorly against players at other positions. Oscar Robertson's 1960-61 was the only PER by a guard higher than Cousy's 21.6 during the period you define, but there were 53 higher PERs recorded by forwards and centers.
Bob Cousy was the dominant passer and dominant guard for a decade, but his best PER rates 492nd? There must be some reason these point guards were voted among the 50 Greatest players of all-time. PER just doesn't get it.
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Charles
Joined: 16 May 2005
Posts: 134
PostPosted: Fri Oct 26, 2007 11:45 pm Post subject: Reply with quote
Conan the Librarian wrote:
The issue of shooting % raises another interesting question about stats like PER as they relate to point guard. PG's, more so than any other position, are likely to take lower % shots with the clock winding down, simply by virtue of handling the ball more. This is not universally true, and I'm not sure how big an impact it would have on shooting %, but it certainly does have an impact. Are PG's to be punished for taking the only available shot late in the clock, even if it is a bad one, rather than risk a 24-second violation and a turnover?
That's a good point Conan
Here are a few other reasons elite point guards are under-rated by PER:
1. While the ball is being advanced in the back court and a play set up there is very little good that can happen statistically from the ball handler's perspective. It's generally either a turnover or nothing.
2. The one-third weight given assists is much too low for many elite play-makers because the impact of individual assists on team scoring is distinctly non-linear.
3. There is no allowance for the psychological boost provided by strong floor leadership. It may be difficult to quantify, but, in a fast paced game like basketball where it is impossible to maintain one hundred percent effort every second of every game, motivation is a huge factor. This responsibilty often lies primarily with the point guard and, just as in every walk of life, some ball players are simply more inspirational than others.
4. I can hear the teeth gnashing over number 3, so here is one that may hold more appeal to people focussed strictly on manipulating traditional stats.
PER assumes that each shot has the same likelihood of being assisted as the team's over-all AST/FGM rate. However, point guards typically have a lower percentage of their shots assisted than the team average.
For example, 63% of Phoenix' baskets were assisted. So, PER assumes that 324 of Steve Nash's 517 made field goals benefited from an assist. But, according to 82games.com, only 23% (or 119) of Nash's baskets were actually assisted. Therefore, one-third of the credit for 205 of Nash's baskets went to a "phantom" assister. That's 137 points that should have stayed in Nash's column.
That's a rather large error and, of course, it's not just Nash. B.Davis (26%), Billups (33%), Miller (29%), Paul (17%), Ridnour (29%), Arenas (36%) and Parker (33%), as well as a few play-making, non-PGs like Wade (27%) and Iverson (26%) are significantly affected by this. Chris Paul had more than two hundred points siphoned off to teammates for phantom assists.
This obviously works in reverse for players who have a higher percentage of their baskets assisted than the team average.
.
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Kevin Pelton
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PostPosted: Sat Oct 27, 2007 12:46 am Post subject: Reply with quote
Charles wrote:
PER assumes that each shot has the same likelihood of being assisted as the team's over-all AST/FGM rate. However, point guards typically have a lower percentage of their shots assisted than the team average.
An excellent point.
From one of my old posts on the subject:
"Another interesting pair is Steve Nash (assisted 20% of the time) and Shawn Marion (73%). By PER, they were basically equivalent per-minute; 21.55 and 21.17, respectively. Add in assists and Nash has a commanding 23.61-20.21 advantage."
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Conan the Librarian
Joined: 03 Sep 2007
Posts: 35
PostPosted: Sat Oct 27, 2007 2:02 am Post subject: Reply with quote
Quote:
PER assumes that each shot has the same likelihood of being assisted as the team's over-all AST/FGM rate. However, point guards typically have a lower percentage of their shots assisted than the team average.
For example, 63% of Phoenix' baskets were assisted. So, PER assumes that 324 of Steve Nash's 517 made field goals benefited from an assist. But, according to 82games.com, only 23% (or 119) of Nash's baskets were actually assisted. Therefore, one-third of the credit for 205 of Nash's baskets went to a "phantom" assister. That's 137 points that should have stayed in Nash's column.
That's a rather large error and, of course, it's not just Nash. B.Davis (26%), Billups (33%), Miller (29%), Paul (17%), Ridnour (29%), Arenas (36%) and Parker (33%), as well as a few play-making, non-PGs like Wade (27%) and Iverson (26%) are significantly affected by this. Chris Paul had more than two hundred points siphoned off to teammates for phantom assists.
This obviously works in reverse for players who have a higher percentage of their baskets assisted than the team average.
Couldn't this be at least partially addressed by determining the average % of baskets assisted for each position, and weight for assist credit accordingly? I know this gets into gray areas about positional definitions (is Wade a PG or SG?), but it seems like it might be a worthwhile endeavor if no one's done it before.
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benji
Joined: 31 Dec 2004
Posts: 32
PostPosted: Sat Oct 27, 2007 3:07 am Post subject: Reply with quote
Why not just use the 82games value?
The PERs I got are slightly off from Hollingers and elsewhere, but this is just for a quick example:
nash,steve 23.6
stoudemire,amare 23.0
marion,shawn 20.7
barbosa,leandro 18.3
diaw,boris 12.9
bell,raja 11.9
thomas,kurt 11.4
banks,marcus 11.2
jones,james 10.7
Using assisted rate from 82games.com, I get:
nash,steve 26.0
stoudemire,amare 22.8
marion,shawn 19.8
barbosa,leandro 18.3
diaw,boris 13.2
banks,marcus 12.3
bell,raja 11.2
thomas,kurt 10.9
jones,james 9.8
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Mike G
Joined: 14 Jan 2005
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Location: Hendersonville, NC
PostPosted: Sat Oct 27, 2007 7:35 am Post subject: Reply with quote
I don't know when the basics of PER were being hatched out, but not that long ago PG's were very well represented in annual player rankings.
Using b-r.com's Player Stats Search, I looked for best PER seasons by PG's. Actually I selected the position "Guard" and looked for seasons with at least 2000 minutes and an Ast/40 rate of >6. This lets in a few Jordan and Wade seasons, but they were defacto points anyway, for many of their minutes.
If PG is an 'underrated' position, then on average there might be fewer than 10 PGs among the top 50 PER's, fewer than 20 among the top 100, etc. Actually, by my operational definition (>6 Ast/40), I've added a positive attribute, and I expect more than 1/5 of any slice to be PG's (so defined).
In the 5-year interval 1988-1992, the 20th best PER among 'PG' was 22.2, while the 100th PER among all players was 19.7. So we might say the positional-median #20 season was 19.7, which was 2.5 PER points lower than the #20 PG season.
Code:
1988-92 1993-97 1998-02 2003-07
#20 22.2 20.6 20.7 21.0
100 19.7 19.7 19.9 21.0
PG 2.5 .9 .8 .0
#40 18.4 18.5 18.4 18.6
200 17.4 17.3 17.5 18.1
PG 1.0 1.2 .9 .5
#60 17.4 16.9 16.6 16.6
300 15.9 16.0 15.8 16.2
PG 1.5 .9 .8 .4
#80 16.0 15.9 15.0 15.1
400 14.8 14.8 14.4 15.0
PG 1.2 1.1 .6 .1
100 15.4 14.5 ---- 12.9
500 13.3 13.6 12.3 13.3
PG 2.1 0.9 -0.4
At every level, the PER status of point guard has fallen steadily since the late-'80s. I am pretty sure there was just a wealth of talent at the position, until it fell off in the mid-late-'90s. (From '98-'02, there weren't even 100 qualifying PG seasons, and I pro-rated 1999).
John H may have tested his PER formula on the recent past and found plenty of PG's among the best players every year. At that time, perhaps the late '90s seemed like an anomaly that would pass; but in fact, the trend has continued. Top-notch PG's are fewer, and 2nd-tier and middling PG's are in even shorter supply than 10 or 20 years ago.
Note that with expansion, total numbers of players at any PER level have risen. This is part of the PER definition. Counter to that trend, PG PER's have dropped in number. Per-team, that trend is even worse.
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Harold Almonte
Joined: 04 Aug 2006
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PostPosted: Sat Oct 27, 2007 10:36 am Post subject: Reply with quote
Quote:
1. While the ball is being advanced in the back court and a play set up there is very little good that can happen statistically from the ball handler's perspective. It's generally either a turnover or nothing.
Quote:
PER assumes that each shot has the same likelihood of being assisted as the team's over-all AST/FGM rate. However, point guards typically have a lower percentage of their shots assisted than the team average.
The A/FGM and even Assists weights is something that could probably be fixed some day by linear ratings. But about the first point, Ratings compute points and gain/lost possessions translated to points (one final economical result, not the total cost of each part involved in the process). There´s no value nor sharing for keeping the possession saved or processing it (ballhandling, the relationship Passing (Pot. assists)/TO, etc.) and that´s assumed like intangibles (in other words, pont guarding is assumed like intangible). Some ratings adjust for no tangible defense (also pseudo-arbitrary), probably an offense adjust could be also made in this case, but something better and wider than "overall A/FGM rate". At least PER´s usage is a step ahead from others ratings.
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UGA Hayes
Joined: 30 Jun 2007
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PostPosted: Sat Oct 27, 2007 1:18 pm Post subject: Reply with quote
I don't have much background in statistics, but I too have thought PG are underrated by PER. I've wondered why you guys don't consider factoring in team stats into your individual evaluation.
To me there is a stat that doesn't really exist for PG but is critical to their evaluation
If you watch the Suns, Nash holds the ball for an inordinate amount of time during a teams's possesion. As a result he accumulates a lot of assists and turnover BUT his teams are perenially among the lowest in Turnovers. Shouldn't he get dome sort of statistical brownie point for that.
Ideally there would be a stat that somehows incorporate team offensive effeciency and TO per time the ball is in a player's hand.
IMO there is a chance that Hollinger's dictum that players can't make other players better is wrong. From what I remember he used PER to make that assertion, but in my opinion the equation for PER has some potential ways of masking this phenomenon of "making teammates better". I'd love to see Hollinger repeat his study b/c I suspect guys who maintain the same PER with different PG might see an increase in their own TO, which is masked by their increase in usage rate. If a PG reverses those two stats isn't he really making others better, even if they maintain the same PER.
Couldn't this explain why the AI to Denver experiment didn''t work the way he expected. After all isn't there only so much "usage rate" to go around. I would expect the aggregate usage rate of teams across the NBA to be pretty universal regardless of personnel. Isn't their value to the PG playing alchemist and figuring out who to distribute to in hope of finding gold (i.e higher tema percentages lower TO, something that wouldn't be attributed to the PG in PER)
I'm curious to know how statistician feel about this.
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asimpkins
Joined: 30 Apr 2006
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PostPosted: Sat Oct 27, 2007 2:34 pm Post subject: Reply with quote
I think you're definitely on to something when you talk about how players can influence each other in multiple ways -- such as decrease turnovers but decrease usage rate as well. Too often people focus on one aspect and then make an overall claim.
I think Hollinger is still more right than wrong about the "making players better" argument because it is ultimately too simplistic. Players influence each other in a lot of ways and it's usually not a simple better or worse outcome.
Shaq gives you better shots but fewer of them. He's not making you better or worse as much as he's changing your role. Joe Johnson left the Suns for Atlanta and his shooting percentage went down but his usage went up. His role changed.
If you took a terrible player and substituted him in for Kobe Bryant a lot of the Lakers would get better because they'd suddenly have a lot more possessions to use their talents. But you'd never see that terrible player get credit for making his teammates better.
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Mountain
Joined: 13 Mar 2007
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PostPosted: Sat Oct 27, 2007 3:48 pm Post subject: Reply with quote
Mike I wonder what your PG vs all positions comparison thru time would show on assist/40 for PGs and for 3 point shot frequency and accuracy for PGs and everyone thru the distance changes and perhaps also FTAs for each thru changes in handcheck enforcement if that can be segmented agreeably.
Did the 3 point shot and the increase in the number of players who could take them proficiently make PGs somewhat less valuable as a passer? Has it cut into their usage?
Does the decline of post players also contribute to a decline in PG PER value from assists?
Would you have interest in breaking out the parts of the PG PER decline?
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thref23
Joined: 13 Aug 2007
Posts: 90
PostPosted: Tue Oct 30, 2007 1:24 am Post subject: Reply with quote
From a logical standpoint, I am not sure why PGs would be underrated more than players at any other position. PER has obvious and unavoidable imperfections, most notably that the stats utlized to create PER are insufficient to measure defensive performance. My point being - many elite PGs are known for their offensive ability - and not their defensive ability. After all, if one were to assume that defense from the PG position was as important as offensive impact, then Steve Nash wouldn't come close to being one of the league's best players. He might be a borderline allstar.
So if PER lacks a relevant defensive measure, and many PGs can be measured more accurately than any other position simply by measuring offensive performance, I would hypothesize that the PG position generally is measured more accurately than any other position using PER.
But that would mean that PGs would be less likely to be overrated by PER as much as they would be less likely to be underrated. I think the question here perhaps should not be "are elite PGs underrated by PER," but rather, something to the extent of "are elite bigs overrated by PER," or something to the extent of, "does PER overweight rebounding slightly."
I'll also add that, if evaluated by players' career PERs, elite PGs are not as noticeably underrated as they are when measuring all-time single season best PERs.
For what its worth, I not too long ago put together overall player composite scores (for 2006/7) which combined a barrage of time position and to a lesser extent team adjusted stats including +/- and counterpart PER. PER itself counted for 20% too, but only for 20%. The concept was founded by Jon Nichols' who has posted here and posted his own defensive and offensive composite scores. I came up with my own modifications and put together my own scores which I feel came out accurately enough as I felt they did a good job of explaining teams' win/loss records (described in a separate thread).
Anyways, if the scores I came up with are considered accurate, then by comparing composite score rank to PER rank, we are able to try and statistically guage which players were most overrated or underrated by PER last season. I find that the 10 most overrated are, in order:
warrick,hakim
curry,eddy
harrington,al
mohammed,nazr
nocioni,andres
okur,mehmet
villanueva,charl
szczerbiak,wally
randolph,zach
humphries,kris
All score low defensively, and almost all could be considered PF/Cs (which is somewhat expected, as I consider defense more relevant from front court positions, especially from the center position, and that factored into composite scores). Hakim Warrick and Eddy Curry, btw, both score more than 150 spots higher in rank by PER versus their overall score rank.
As far as the players most underrated by PER, in order:
battier,shane
bowen,bruce
bell,raja
alston,rafer
parker,anthony
najera,eduardo
garbajosa,jorge
pavlovic,sasha
ross,quinton
posey,james
All are known as good defensive players, and all are decent shooters except for Quinton Ross and Najera. Shane Battier scores 188 spots higher in overall rank versus PER rank. Ironically, only three guys on the list could be considered front court players.
Far as PGs, the most underrated:
alston,rafer
jones,damon
duhon,chris
fisher,derek
gibson,daniel
(all are decent shooters)
the most overrated:
rodriguez,sergio
ford,t.j.
knight,brevin
banks,marcus
tinsley,jamaal
(none are good shooters)
Steve Nash, Deron Williams, Jason Kidd, and Chris Paul are shown to be very, very slightly underrated by PER last season
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Mike G
Joined: 14 Jan 2005
Posts: 3605
Location: Hendersonville, NC
PostPosted: Tue Oct 30, 2007 4:52 am Post subject: Reply with quote
Statman wrote:
Mike G wrote:
It just seems to me that players shoot well because they are good shooters; or not. Shooting 38% in a 38% era is no better than shooting 38% in a 48% era.
While I agree with the vaste majority of things you normally say - this I completely disagree with. Obviously (to me) shooting 38% in a 38% era is better than 38% in a 48% era - since your points per possession relative to the league is better.
Now - if you are making a point about shooting ability - I'd also disagree, but to a lesser extent. Part of the reason league shooting %'s were so much lower in the past can be related to many factors outside of shooting ability. Much harder rims, much more physical defensive play, coaches not having yet developed decent offensive sets to get players better open looks, no illegal defense, etc.
Bob Cousy shooting 38% in a 38% shooting league is a whole lot better than a player shooting 38% in a 48% league in my book.
I gather that you disagree with something here!
But really, neither of us knows how Cousy would do in a league 50 years along. Nor whether Tony Parker would drive with impunity against Macauley and Loscutoff.
Coaching wasn't as advanced. Doesn't that mean the game wasn't played to quite the level it is now? Aren't jump shots better than set shots? Aren't guys who can dribble with either hand better than those who can't?
Would Cousy shoot as well as the league around him? He peaked at .397 in 1955, when his team was making .398. He again hit .397 in '63, when his team was hitting .426. This on a team with many options.
Now, if your point is that a player or a team will be more successful when shooting better than the competition, of course this is correct. But I think it's even more absolutist to say the league is always equally competitive, regardless of wholesale changes. When Cousy won MVP in 1957, there was exactly one good black player in the NBA, and he was on the same team.
I have no reason to believe NBA offenses have evolved any more effectively than defenses have. If anything, better coaching means advantage: defense.
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Charles
Joined: 16 May 2005
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PostPosted: Wed Oct 31, 2007 11:52 am Post subject: Reply with quote
Suppose winning the Finals MVP goes to Tony Parker's head and he decides he will take a couple of extra shots per game this season. These extra shots figure to be more difficult, so let's further suppose that Parker is only 80% as effective on them. The result is that while Parker's scoring increases from 18.6 to 20.6, he loses about half an assist per game and his true shooting percentage drops from .572 to .559.
Is this a good change for Parker? It's certainly good for his contract negotiations. Not only has he moved above the magical 20 ppg mark, his agent can also argue that his PER has risen a point to 22.1.
Is this a good change for the Spurs? Well, although Parker figures to score more as an individual, the Spurs figure to score 35 points less as a team. So, unless Parker can maintain something closer to his current efficiency, he shouldn't be taking those shots (not to mention, point guards who take too many shots risk alienating their teammates.)
I understand that jacking up a player's PER based on points per game helps keep it in sync with public perception, but, in the real world, forcing up bad shots does not make you a more valuable player.
Ps. with an extra ten extra shots a game (at 80% efficiency) Parker would move into Allen Iverson territory with 29.0 ppg, a below average TS% and a PER of 25.4. Then he'd be even more valuable to the Spurs than Tim Duncan... PER-wise.
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asimpkins
Joined: 30 Apr 2006
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PostPosted: Wed Oct 31, 2007 12:09 pm Post subject: Reply with quote
Charles wrote:
I understand that jacking up a player's PER based on points per game helps keep it in sync with public perception, but, in the real world, forcing up bad shots does not make you a more valuable player.
But it all depends. If he's forcing up bad shots when his teammates could have taken better ones then it is bad. But if he's putting up bad shots when his teammates would have done even worse then it is a good thing.
It all depends on when the bad shots are happening and what the team's needs are. But this information is not available to PER because it's not available in the box score. So PER attempts to make the best one-size-fits-all estimate, and it can hardly be expected to do any better.
It has always been meant to be used in conjunction with other kinds of analysis. One team may need a higher usage player and another may not. PER won't tell you this, you have to scout that out yourself.
thref23 wrote:
From a logical standpoint, I am not sure why PGs would be underrated more than players at any other position. PER has obvious and unavoidable imperfections, most notably that the stats utlized to create PER are insufficient to measure defensive performance. My point being - many elite PGs are known for their offensive ability - and not their defensive ability.
I agree. If PGs don't have many intangibles counted in running an offense, then big men miss out on the intangibles they offer being the center piece of the defense. Ultimately, couldn't it just be that big men are on the average more valuable than PGs?
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Charles
Joined: 16 May 2005
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PostPosted: Wed Oct 31, 2007 3:23 pm Post subject: Reply with quote
asimpkins wrote:
Charles wrote:
I understand that jacking up a player's PER based on points per game helps keep it in sync with public perception, but, in the real world, forcing up bad shots does not make you a more valuable player.
But it all depends. If he's forcing up bad shots when his teammates could have taken better ones then it is bad. But if he's putting up bad shots when his teammates would have done even worse then it is a good thing.
Absolutely. The question is does PER reflect that volume/efficiency balance correctly. That's why I defined a specific situation where you can test the change in individual PER vis-a-vis the change in team scoring. It's just math. And the result is that Parker's PER goes up, despite the fact that the Spur's team scoring goes down.
If you change the input on the assumption that Parker maintains his TS% on those extra shots, what happens? His scoring and PER rise even more, while his teammate's PERs suffer and the Spurs, as a team, pretty much break even. Again, a rise in individual PER reflects a increase in the player's glamor stats (and perceived value) , but not necessarily an increase in the team's performance.
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asimpkins
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PostPosted: Wed Oct 31, 2007 5:05 pm Post subject: Reply with quote
But is there any set of values you could set for PER that would be completely immune to coming up with a scenario like you did where an individual player was benefiting at the expense of the team? (Or was not being properly credited for helping his team?)
Sure, in your scenario Parker was overshooting -- which we know because we watch the Spurs and know what the rest of the team was capable of. We could adjust PER to appropriately fit Tony Parker and the Spurs. But then another player on a weak offensive team will be incorrectly penalized for putting up lots of tough shots to keep his incompetent teammates from turning it over.
You can't tell a good shot from a bad shot by the box score.
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Harold Almonte
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PostPosted: Wed Oct 31, 2007 8:49 pm Post subject: Reply with quote
Can this "individual volume/efficiency balance" be balanced with some kind of team eff. adjust, or team volume (+/-) adjust? Then, if Parker wants (or needs) to increase his stats hurting the team and teammates's stats and ratings, there must be a cost for him from the team's results (and the opposite). That's to be assisted, or unassisted, on every stat. I also don't buy the argument that Iverson was just an average player the Sixers almost champs season, according to all ratings.
All this stuff was discussed before in the "diversified offense" topic, and it's also why some people try to make compounds ratings, counterpartings, etc. Maybe some ratings reward volume a little more while others thinks that efficiency (from a league average) is the only thing that matters. But the team context must be expressed inside a rating, not only player's skills. Another kind of balance.
That's why RebR% is probably the best isolate stat rating, because a player is rated against himself, opponents and teammates. WP's team defense adjust is an aceptable way to include the team context, although not perfect given that credits are assigned by play time, not by attempts, or on/off (or yes?). How can players's scoring be rated against teammates? And passing? How can we say in a formula that some players, even having a high FG%, low TOs, aren't good scorers in the sense that they are not as reliable for the most doable and relative easy scoring plays to be set for them, even if they are spotted right under the ring? How can we know a player is in good/bad over-usage mode?.
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Ryoga Hibiki
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PostPosted: Mon Nov 05, 2007 12:24 pm Post subject: Reply with quote
PER is influenced by volume scoring (overrating it, imo), more than anything else, so you'll likely see scorers among the top players.
PGs are very rarely volume scorers, that's why they don't score big on PER.
Btw, what's PER's balance of usage/efficiency?
Roughly, taking a 35% 2pt shot increases a player's PER, isn't there something wrong?
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John Hollinger
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PostPosted: Mon Nov 05, 2007 3:56 pm Post subject: Reply with quote
Thought I'd finally chime in on this, because there's one thing I think that's being missed. Basically, folks are only looking at the top half of the spectrum. You'll notice that not only are PGs underrepresented at the very top of the rankings, they're equally underrepresented at the very bottom.
This is to be expected -- we would anticipate much more variation between the best and worst players at the frontcourt positions than in the backcourt, because of the simple fact that there are so few people alive who are that size to begin with. Thus, teams are picking from the extreme right of the talent curve at the "normal" heights that most point guards are, but edge much closer to the middle by the time they get to 7-footers. And thus the variation between the best and worst bigs is going to be much, much larger.
And that, in turn, tends to be why teams value big men much more highly than guards ... at least when actual money is involved
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Mountain
Joined: 13 Mar 2007
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PostPosted: Mon Nov 05, 2007 10:23 pm Post subject: Reply with quote
Re: Breaking out the parts of the PG PER decline
On average the top 150 PG seasons of 2002-3 to 2006-7
defined as >6 assists per 48 / not an obvious non guard and sorteed by minutes (safely over 2000 for season)
compared to the top150 PG seasons of 1988-89 to 1993-94 (chosen as just prior to the major increase in 3 pt shooting frequency, a factor being tested as a major change agent) ...
made 0.9 less FGs and shot 3.7 %pts worse overall but made 2.0 more 3 ptrs and shot them 3.6 % points better.
They made 0.3 more FTs (perhaps due to handcheck enforcement) but ended up scoring 0.8 less points.
They had 0.5 less ORs- one-third less (perhaps more time overall behind 3 pt arc?).
They had 1.5 less assists.
All per 48 minutes.
(though in a bit under 4% less actual minutes)
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Mountain
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PostPosted: Wed Nov 07, 2007 12:32 pm Post subject: Reply with quote
I update because I forgot to mention the pace change in the notes. I assume because of the timing of the pace change it was caused primarily by the heavier usage of the 3 pt shot but haven't stuidied or tested that in detail.
The onset of the major 3 pt usage era saw PGs using this weapon more but gave it to many others too and we see PG FGAs down as a raw per game amount and assists down too. Overall team field goal attempts down by maybe 7% perhaps as teams passed and passed looking to end up with the 3 pt shot? PG share of FGAs actually crept under from 21.7 to 22.2% But the reduction in shots per game and assists and the other negative changes outweighed the positive changes that helped their PERs.
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Charles
Joined: 16 May 2005
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PostPosted: Tue Nov 13, 2007 2:19 pm Post subject: Reply with quote
John Hollinger wrote:
-- we would anticipate much more variation between the best and worst players at the frontcourt positions than in the backcourt, because of the simple fact that there are so few people alive who are that size to begin with. Thus, teams are picking from the extreme right of the talent curve at the "normal" heights that most point guards are, but edge much closer to the middle by the time they get to 7-footers. And thus the variation between the best and worst bigs is going to be much, much larger.
The fact that there are more six footers than seven footers in the general population does not imply that good NBA play makers are easier to find than good NBA rebounders. In fact, the variance in assists is usually significantly higher than the variance in rebounds. For instance, here are the top thirty assisters and top thirty rebounders from last season.
Code:
Avg Max 30th StDev
Assists per 48 minutes 9.0 15.8 6.8 2.2
Rebounds per 48 minutes 13.7 17.2 10.8 1.7
Yes, when you look at PER, point guards have both the lowest max ratings and least variance. However, the argument is circular. This is exactly what you would expect to find when play-making is under-valued vis-a-vis shot making.
Code:
---- PER ----
Pos Players Max StDev
1-PG 27 24.0 3.9
2-SG 26 28.9 4.8
3-SF 25 24.5 4.3
4-PF 31 27.6 5.1
5-C 31 26.5 4.5
However if, rather than PER, you use an independent measure such as plus/minus, the story changes. Now, point guards, join power forwards as having both the largest overall impact and the largest variance. Centers - despite the fact that seven footers are rare at the shopping mall - have, by far, the least positive impact and the smallest standard deviation.
Code:
---- Adjusted Plus/Minus ----
Pos Avg StDev
1-PG +1.1 4.4
2-SG +0.5 3.7
3-SF +0.9 3.8
4-PF +0.9 4.8
5-C -0.6 2.8
(I realize plus/minus is noisy at the player/season level, however, it appears to be quite valid when aggregated in this way. Certainly more valid than guessing at what weights to apply to individual statistics.)
More and more teams are figuring out that, in the modern game, tall, immobile players are rarely difference makers.
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Charles
Joined: 16 May 2005
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PostPosted: Tue Nov 13, 2007 2:32 pm Post subject: Reply with quote
John Hollinger wrote:
Thought I'd finally chime in on this, because there's one thing I think that's being missed. Basically, folks are only looking at the top half of the spectrum. You'll notice that not only are PGs underrepresented at the very top of the rankings, they're equally underrepresented at the very bottom.
Yes, this is exactly what I mean by "elite point guards are under-rated." The range from the top to the bottom is much too small. According to PER no point guard has had a "Strong MVP Candidate" season in 43 years. Magic managed a couple of "Weak MVP Candidate" seasons. But, Stockton, Kidd and Nash are doing well when they occasionally crack the "Bona fide All-Star" barrier.
I am not criticizing the particulars of the method. I am just pointing out that this type of thing (a one-size-fits-all linear weights formula) is bound to be biased in one way or another and this one greatly under-values elite point guards. People might want to be aware of that when they make judgments based on these numbers.
Actually, I think any method of this type will have problems with elite playmakers because assists, more than any other factor, tend to have a powerful non-linear impact.
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Mike G
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PostPosted: Thu Nov 15, 2007 10:24 am Post subject: Reply with quote
Charles wrote:
... this type of thing (a one-size-fits-all linear weights formula) is bound to be biased in one way or another ...
Well, they don't all have to be biased against elite passers. I give assists 1.33 times the weight of a point scored (at average efficiency). Surveying player seasons of >2000 minutes, for 20 years (1987-2006), I see Jordan's 1989 at the top of my 'T rates', when he was actually playing the point.
I forgot to pro-rate 1999, so it's out. And I'm left with the 100 best seasons from each year to sort from: 1900 player-seasons. I expect to find 20% of any large slice to be (arguably) PG's.
After MJ, the competition is thick with Shaq, Hakeem, DRob, Ewing, Barkley, Malone, etc, etc. Only 9 of the top 100 seasons belong to PG's, 4 by Magic; also Lebron'05, Wade'06, Stockton'91, and Brandon'96. These are all superstar-level seasons.
But in the 2nd 100 -- still the top 10% -- I find 31 PG-seasons: exactly 40 of the top 200. A single Drexler season ('92) that might be called iffy (as in, is he a PG?). Still using 'guard with 6.0 Ast/36' as the criteria. All these are solid Allstar-level seasons.
From the top 400, there are 103 PG-seasons. Supposing there are as many as 23 non-PG's (there aren't) who slipped into the list, we are still at 20%. So it is certainly possible for a 'linear-weight system' to rank top-flight PG's in agreement with their generally-perceived worth.
Here are the PG-like players making the top 200 seasons since '87 (showing # of times and first year of appearance):
Code:
# player year
9 Stockton 88
5 Magic 87
3 K Johnson 90
3 Payton 97
3 Kidd 99
2 Brandon 96
2 Wade 05
1 Jordan 89
1 Drexler 92
1 Price 94
1 A Hardaway 96
1 T Hardaway 97
1 Cassell 04
1 Davis 04
1 Iverson 05
1 James 05
1 Billups 06
1 Nash 06
1 Parker 06
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mathayus
Joined: 15 Aug 2005
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PostPosted: Sat Nov 24, 2007 7:13 pm Post subject: Reply with quote
My take:
1) Distributors (be they point guards or whatever) are systematically underrated in flat PER because of the assumed flat assisted basket percentage.
2) Distributors are typically underrated in stats in general because it's hard to accurately quantify their impact. I don't think the value of an assist is underrated, but I do think the impact of a good floor general in setting up a basket goes beyond the moment when he makes a pass to someone who then makes a shot. It's a less dramatic example of block shots where the main value of a shotblocker is not in the shots he blocks but in the shots he alters.
Harold Almonte
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PostPosted: Mon Nov 26, 2007 9:02 am Post subject: Reply with quote
mathayus wrote:
Quote:
1) Distributors (be they point guards or whatever) are systematically underrated in flat PER because of the assumed flat assisted basket percentage.
It's probably a two edges sword thing, because once you apply a basic assisted factor: Points(1-1/3*playerAd%), then PGs would be automatically overrated, and you would need to adjust for how assister are your teammates first (including your PG): LgAd%/TmAd%, and even for a player not being given the opportunity to be the main distributor and ball toucher: some kind of position adjustment, where being the PG would be (1) unit, and little increases depending on how far from PG duties a player makes offensive.
What I think is the only way a PG to be rated at real worth is accounting potential assists rate (probable assists that scorers waste), and assist percentage from FTs. Probably (but I'm not really sure), you would need to add extra credits for the extra point of a 3point-assist.
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mathayus
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PostPosted: Tue Nov 27, 2007 7:31 pm Post subject: Reply with quote
Hmm. Been a while since I analyzed the PER formula so maybe I'm missing something. When you replace guesstimates with the actual correct numbers, what's the problem? Yes it's possible that that could make people feel that the stat overestimates point guards, but if that's the case then the problem is with PER as a whole not this specific change (and them liking the PER previously wasn't based on the math but simply based on their own notions of how the results should look).
To the general idea of factoring in opportunity, that's not an unworthy goal, however the problem it addresses is not something introduced by this adjustment. Every aspect of this game of 1 ball with 5 guys simultaneously biases classical statistics toward the guy with the ball.
As far as truly capturing the impact of a great point guard, I'm skeptical we can do it. Case in point: We know that coaches have an impact on the final score, and that they influence it as the game happens by means of communicating with players, and I think we know that there's no way to really measure that value per action objectively. A great point guard, and really any leader for that matter, affects the game in the same way, hence the nicknames "floor general" "quarterback" "coach on the floor". As a result it just seems like a given that even the stat that perfectly measures resulting action will underrate such players due to not being able to factor in the cause statistically.
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Harold Almonte
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PostPosted: Wed Nov 28, 2007 8:26 am Post subject: Reply with quote
Agree. Intangibles can't be directly measured (just the effects), nor a little more tangible thing like ballhandling (passing is just a piece of this). The fact is that it's very difficult to define that a player is a better scorer (compared against another one with the same volume and efficiency level) because he opts or is obligued to assist himself in the most of cases, and would be also difficult for us (and a lot more for WOW followers) to downgrade a superscorer and supereficient player like Kevin Martin, because he needs to be assisted more than a 60%.
But, you can look it at this way: PGs are responsible to protect (almost all)the possession between the acquiring and the attempt, then that would makes you think that a lot of credits aren't being accounted for them.
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mathayus
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PostPosted: Tue Dec 11, 2007 8:28 pm Post subject: Reply with quote
Harold Almonte wrote:
Agree. Intangibles can't be directly measured (just the effects), nor a little more tangible thing like ballhandling (passing is just a piece of this). The fact is that it's very difficult to define that a player is a better scorer (compared against another one with the same volume and efficiency level) because he opts or is obligued to assist himself in the most of cases, and would be also difficult for us (and a lot more for WOW followers) to downgrade a superscorer and supereficient player like Kevin Martin, because he needs to be assisted more than a 60%.
But, you can look it at this way: PGs are responsible to protect (almost all)the possession between the acquiring and the attempt, then that would makes you think that a lot of credits aren't being accounted for them.
Not sure what you're asking exactly. We can easily get an estimate for turnovers per possession, and that's good, but I can't imagine that being thought to precisely measure a point guard's impact as it's really a team measurement, and if we're opening up the door to team measurements, isn't that giving up on figuring everything out purely by individual action? And I say this as someone who really is an advocate of some team based stats to help evaluate individuals, just not as someone who thinks you can ever get truly fine precision that way.
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Harold Almonte
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PostPosted: Tue Dec 11, 2007 9:25 pm Post subject: Reply with quote
The problem with boxscore stats (like TOs) is that you can reward or punish as much as the existency of that stat, you can't do anymore. If a PG doesn't commit TOs protecting the possession, you don't punish, but not to punish is not to reward, and it has some possession credit, and all credits can be translated to points. When you fail to rebound against an opponent you are not credited, but not to credit is not to punish. When a PG gives a bad pass before a FGMissed, he's not punished with a bad assist, and so on.
A PG is supposed to receive some credits by doing the ballhandling job for some scorers, but those scorers, even not being skilled enough to get open from his defender for an easy shot handling the ball, they probably can do it without the ball. While others can do all of that even without the help of the PG. And then about the assisted factor, you could end being more arbitrary than considering all assists 1/3 of a scored basket.
It's very complicated, and we are losing a lot of game inside stats.
