NBA Advanced Statistics Conversation with EvanZ of Golden State of Mind
by East Bay Ray on Jan 11, 2012 9:15 PM MST
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PrintMichael Lewis' 2003 book "Moneyball" opened the eyes of many to the potential benefits of analyzing baseball by more than simple scouting reports and statistics such as batting average, HRs, RBI, ERA and wins for a pitcher. In the years since, advanced statistics have revolutionized the way MLB front offices value player traits and production, as followers of Oakland A's general manager Billy Beane have spread throughout the sport.
The NBA followed suit, and advanced stats such as win shares, on-court/off-court, offensive rating, defensive rating and rebounding % now influence the decisions of NBA front offices in the same way. No longer are we bound by the basic stats of points per game, rebounds per game and assists per game, all of which are limited by lack of consideration to opportunity and efficiency of production.
Identifying efficient performers on the court is one of the goals of advanced stats analysis, but the larger goal is efficient use of resources by a team. While baseball has no official salary cap (but does have a de facto cap based on a team's revenue), the NBA does and it became a much harder cap with the ratification of the most recent collective bargaining agreement. This makes accurate valuation of players even more important to a franchise's chances for sustainable success.
We here at BSotS have dabbled in advanced stats analysis; we have some experts, some who are put off by it and some curious novices. Our SBN community has somewhat of a guru in the field in Golden State of Mind's EvanZ, who you might remember from a chat we had last summer. Evan participated in another Google chat with me recently as I picked his brain on some of the advanced data he analyzes when judging player effectiveness.
More after the jump.
Ray: When did you start to analyze NBA basketball using more advanced stats than simple PPG, RPG, etc?
Evan: Fairly recently...I think it was spring of 2010.
Ray: What caused you to start?
Evan: Actually, you might not believe this, but it was some time after I joined GSoM. In the beginning I was one of the "anti-stat" guys, but somehow I became convinced after losing countless arguments. After that I was "all in" and it grew from there.
Ray: How is it received at GSoM? Do you still have a wide divide between the stat people and the "anti-stat" people?
Evan: I think it's definitely acknowledged that it's a stat-heavy blog, but there are certainly a minority of folks who don't buy it. They tolerate us though.
Ray: How does analysis of advanced statistical data enhance your understanding of basketball?
Evan: I think it helps you understand "the bottom line" so to speak, what teams need to do to win, vs. what looks good on ESPN or something.
Ray: Does it change the way you watch games?
Evan: Yes, definitely. For example, I cringe when I see "bad shots" that players shouldn't take.
Ray: Haha. Try watching Shannon Brown. Yikes.
Evan: He looks good dunking
Ray: What are some of the data points you find most useful?
Evan: Really...efficiency, that's the number one thing.
Ray: As defined by what?
Evan: Points per possession (PPP). It can be applied to many things, though: at the team level, the player level, the type of play, etc
Ray: Basketball Reference, 82games.com and Synergy Sports are the websites that immediately come to mind with regards to advanced NBA stats. What others have you found to be helpful?
Evan: Hoopdata is the other big one. Oh, and I use Basketball Value a lot for my own metric. It's called "ezPM". There's a brief description of ezPM in "The Primer" (Ray's note: the primer is excellent and I highly recommend it), but basically it puts a value on every possession that a player uses and creates (through steals and rebounds). There's a couple of metrics in the primer that I developed. One is ezPM and the other is PSAMS (position- and shot-adjusted marginal scoring). I also develop metrics here and there when I find something missing in the "field".
Evan: And one more resource...
NBA Appspot
That's where I get the RAPM (regularized adjusted plus/minus) data
Ray: Can you give an example of a player who, according to advanced statistical data, is overrated by most fans?
Evan: Uh, Monta Ellis comes to mind.
(Ray's note: Yes, I am a big Ellis critic. No, I did not pay Evan off for this.)
Evan: Last season, a lot of advanced stats folks thought Rose was overrated - he's actually peforming better statistically so far this season (according to ezPM, anyway). John Wall appears to be highly overrated.
Ray: Underrated?
Evan: A lot of defensive guys like Nick Collison, Luol Deng, Andre Iguodala
Ray: Do you think the existing defensive metrics truly capture a player's value on that end?
Evan: I think RAPM generally does the best job. Unfortunately, there's just not a lot of data aside from blocks and defensive rebounds (which aren't really "defense" per se).
Ray: Obligatory question about the Suns and Warriors: for each team, what player does advanced stats analysis show to be better than we might think? Not as good as we think?
Evan: On the Warriors, it's easily Ekpe Udoh. RAPM has him as an above average player, but according to the box score, he's a zero. But anyone who watches him play see what he brings defensively. That's not captured by the box score. For the Suns, aside from Steve Nash possibly being underrated (I know hard to believe), I'm not sure you have any other players who are that much better than what people think. Markieff looks goooood, BTW, so good on you guys. (Ray's note: Nash is currently rated #6 overall in the league in RAPM.)
Ray: We are VERY excited about Markieff Morris so far.
Ray: Do you see a risk in losing the human element of the game by breaking it down into cold, rational metrics?
Evan: Well, basketball is way behind baseball, so I would ask whether baseball still has scouts? I think so. And that probably means there is still going to be a place for that in basketball for quite some time. Numbers can tell you a lot, but not everything.
Ray: What limitations do you find in statistical analysis of basketball?
Evan: The main limitations all basically boil down to not having enough data. I'll give one obvious example, which would be what I call "potential assists". The box score records an assist when a player scores, but what about when he doesn't score, but should have? Those are not recorded and thus, represent a data limitation. There are many more examples on both sides of the ball. (Ray's note: how many more assists would Steve Nash have this season if he was surrounded by better shooters than he currently is?)
Evan: If folks are interested in ezPM, I am keeping those continually updated on my blog.
Brightsiders, what say you? What value and what limitations do you see in advanced stats? I encourage you to follow the links above; there is plenty more to read.
Please feel free to fire away with your thoughts and questions for Evan, and I'd like to give him a big thanks for his time and expertise.
For more exclusive content, follow us on Twitter @Brightsidesun and "Like" us on Facebook.
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I feel like Basket ball is to fluid.
In Baseball and Football after every play the players reset and know exactly what to do the next play. That way a players advanced stats are more interpretable. you know precically what the out come should be (very little X factor). the reffing is another big factor, again calls like blocking or charging, lose ball fouls are not very cut and dry and subject to interpretation (Is there a Ginobli of the MLB). I’m not saying it can’t be done but it would en-tale a very complex (and still Subjective) system of equations, a profound understanding of mathematical modeling and differential equations along with a mastery of Matrix Mathematics…So ya, there’s that.
"Love me or hate me. Its one or the other…always has been. Hate my game, my swagger. Hate my fade-away, my hunger. Hate that I am a veteran, a champion. Hate that. Hate it with all your heart and hate that I am loved for the exact same reasons." – Kobe Bryant
don't even say it Ray
by 2NASHTY on Jan 11, 2012 10:23 PM MST reply actions 2 recs
Pitches in baseball are decided by the completely subjective strike zone called by the ump.
What is more subject to interpretation than that? Basketball players adjust to the way the refs are calling the game just as hitters and pitchers adjust to the way an ump is calling balls and strikes. I don’t see where officiating compromises the validity of advanced stats at all.
And dammit, 2N, you went and watched the game with the heretics over at SS&R, lost your bet and now you soil our fine blog with that vomit-inducing Kobe quote in your sig line. Tsk tsk.
Blogging Suns basketball for Bright Side of the Sun from California wine country.
Twitter: @EastBayRaymundo
by East Bay Ray on Jan 11, 2012 10:55 PM MST up reply actions
It it wasn't anyone but 2N...
We’d have to torch him…Of course he’d have to wait in line behind Shannon Brown
Maybe we could just banish him to the BEDGE for a week or two…
STAT may be gone but the Suns will rise....! BTW, If positivity is a crime, I plead guilty by reason of T-Bird...!
please no
can’t say shit there and that’s half my blogging Vocab.
"Love me or hate me. Its one or the other…always has been. Hate my game, my swagger. Hate my fade-away, my hunger. Hate that I am a veteran, a champion. Hate that. Hate it with all your heart and hate that I am loved for the exact same reasons." – Kobe Bryant
don't even say it Ray
With your grammar, I'm suprised they understand your cuss words...
Some Liguist expert over at SS&R is probably about ready to hang himself right aobut now…
STAT may be gone but the Suns will rise....! BTW, If positivity is a crime, I plead guilty by reason of T-Bird...!
technically
the suns lost my bet
"Love me or hate me. Its one or the other…always has been. Hate my game, my swagger. Hate my fade-away, my hunger. Hate that I am a veteran, a champion. Hate that. Hate it with all your heart and hate that I am loved for the exact same reasons." – Kobe Bryant
don't even say it Ray
the strike zone
is far less subjective IMO. plus the players don’t interact as much. A good basketball team must gel regardless of how much talent they have.
"Love me or hate me. Its one or the other…always has been. Hate my game, my swagger. Hate my fade-away, my hunger. Hate that I am a veteran, a champion. Hate that. Hate it with all your heart and hate that I am loved for the exact same reasons." – Kobe Bryant
don't even say it Ray
Moreover
Strike zones stay relatively consistent throughout the game. Even if there is fluctuation from ump-to-ump and game-to-game, it is pretty much the same for the entirety of the game.
That is vastly different from gauging someone’s shooting percentage, or even shooting percentage from 16-21 that doesn’t account for the defender, angle to the hoop and amount of open-ness.
Free Steve Nash!
This thread has too much Kobe LOLOL
"If Gortat pulls off a real Dream Shake in-game this year I will shave my head.
Mark my words." Piotr Szczesniak 12/12/11 2:12 PM
Cardinals, Suns, D-backs for life!
Agree.
Good statistics depend on measurement of repeatable events.
Baseball and football have a lot of those, so stats are reliable predictors of future outcomes.
By nature, basketball is a fluid game with few repeatable events, hence its statistics are unreliable.
There’s still no substitute for the sharp eyes and instincts of an experienced scout.
I'm Michael Beasley's imaginary friend.
by suns68 on Jan 12, 2012 12:35 AM MST via mobile up reply actions
By nature, basketball is a fluid game with few repeatable events, hence its statistics are unreliable.
Luckily, such a statement is provable or disprovable, and it’s just not true, and is in fact addressed quite well here: http://wagesofwins.com/faq/
SOME statistics are unreliable, and some are not. In fact, +/- is the most unreliable, and the one I’d place no faith in.
There’s still no substitute for the sharp eyes and instincts of an experienced scout.
Hmm. I wonder how often scouts are measured. I remember the last Lindy’s Pro Basketball I ever bought (sad memory in some ways – I used to love Lindy’s) that had a quote from a scout calling the rookie Adam Morrison a “Can’t miss” prospect. I bet that guy still has a job (just the clown who drafted him does), and really, that is a massive whiff – a sackable offence in, say, the financial community. I wonder if sometimes the “boy’s Club” of scouting isn’t protecting it’s own when confronted by the stats movement.
That's a false dichotomy
There’s still no substitute for the sharp eyes and instincts of an experienced scout.
Nobody’s advocating we don’t use our eyes to judge player value, but our eyes can deceive us and bias always creeps in. Of course we can’t say a player is good or not based on numbers on a page without seeing him play, but there also has to be an objective measure of production and advanced stats provide that.
Blogging Suns basketball for Bright Side of the Sun from California wine country.
Twitter: @EastBayRaymundo
by East Bay Ray on Jan 12, 2012 10:08 AM MST up reply actions
Good stuff EBR and EvanZ
My feelings on scouts vs statistics:
The difference between a scouts eyes and raw numbers are three – scouts eyes can’t be there all the time, human memory is faulty and human bias is unavoidable. Numbers see all, remember all and are unbiased.
Now a common argument is that numbers miss much and therefore aren’t trustworthy, but I disagree. The system (how we use the numbers) misses much, which is why we’re always working to improve it. But in a valid system, numbers never lie.
Blaming statistics for not showing the full picture is much like blaming your wrench for your engine not starting. The wrench is a tool, and does exactly what you ask if it, perfectly, every time. The fact that your car is out of gas is a failure of the system (application of the tools).
In a roundabout way I’m getting to my point: statistics always give the right answer if the question is asked properly.
borderline adequate
okay...
In a roundabout way I’m getting to my point: statistics always give the right answer if the question is asked properly.
What does my ass always itch at 3PM…? E ery formula I’ve tried doesn’t come up with the right anwer…
STAT may be gone but the Suns will rise....! BTW, If positivity is a crime, I plead guilty by reason of T-Bird...!
Probably proportional to amount of Thunderbird consumed.
Blogging Suns basketball for Bright Side of the Sun from California wine country.
Twitter: @EastBayRaymundo
by East Bay Ray on Jan 12, 2012 2:32 PM MST up reply actions
You asked:
What does my ass always itch at 3PM…?
I counter with:
if the question is asked properly.
“What does my ass itch” is most definitely not the proper way to ask that question.
Go Suns, Packers, Jays, and Huskers!
Read my thoughts on Creighton University athletics at Creightonian.com
I also edit things at Ridiculous Upside. Check it out.
Very well put, wax.
What I don’t understand is that many of the same people who bristle at stats like win shares or ezPM or RAPM have no problem throwing around PPG, RPG or APG. Raw scoring, assist and rebounding numbers are flawed as hell. Why resist attempts to improve upon them?
Blogging Suns basketball for Bright Side of the Sun from California wine country.
Twitter: @EastBayRaymundo
by East Bay Ray on Jan 12, 2012 2:31 PM MST up reply actions
Good point 2Nashty!
You’re right…the human element in all sports is very difficult to separate, or isolate, when dealing with statistics. This is the exact reason that many people discount stats as only telling part of the story, and in some instances leading to false conclusions.
For instance, I’m sure we’ve all looked at stats like the +/- in basketball from time to time and laughed at how inaccurate this one measurable can be. Look at the last game against the Lakers for example…Ronnie Price was our only player in the positive with a +3, while Nash had the second worst rating (-19) on the team. If you went solely by this, then Nash played like garbage and Price should have been starting. Or how about Lopez playing pretty well (0pts, 2rbs) with merely a -1, while Gortat stunk up the joint with his 16pts and 12rbs (-15).
Taking this stat at face value would be absurd because we all know that there is much, much more to the story. But some of these newer and more in-depth advanced stats, such as the ones being talked about by Ray and Evan in this article, do a better job at accurately representing the actual impact of each player.
All in all I think we still have to look at stats with a filter for common sense…I am beginning to trust certain stats more than I ever used to though because they are also evolving for the better, but by and large they still aren’t able to tell the whole story just yet…at least not in my opinion anyway.
Absolutely awesome write up Ray!
I’m just beginning to get into advanced stats and learning to trust them as much as, or more than, my own eyes.
The links to those sites that you and EvanZ mentioned are much appreciated. So far, the data I have studied seems to do a fairly good job of discerning efficient players from those who are simply overhyped. I’m slowly transitioning to this new way of analyzing players and I think you and EvanZ did a great job in introducing and explaining it.
by 7footer on Jan 11, 2012 11:36 PM MST via mobile reply actions
Read Wages Of Wins
http://wagesofwins.com/ – they have a much smarter analysis in many ways, at least in my opinion.
my advice to you is to go a bit further down the rabbit hole
you’ll find that Berri doesn’t know as much as you think he does, or as much as he thinks he does, to be honest.
Anyway, I was at the same place you are a little over a year ago. You’ll get there. Just keep digging.
And your credibility just skyrocketed.
you’ll find that Berri doesn’t know as much as you think he does, or as much as he thinks he does, to be honest
by Bullet Nation in Exile on Jan 12, 2012 12:12 PM MST up reply actions
ditto
;)
J-RIDAH: Its not 1 player in this draft better than Monta or Lee. Anthony Davis is no different than Al Farouq Aminu. Andre Drummond could be good but he is not impressive at this point at all besides his size. This draft is hella overated.
I've often resisted advanced stats analysis
simply because Dave Berri and WoW are paraded about as gospel by most stat heads, and while you had me curious, I’m definitely taking a look…so thanks :)
by Bullet Nation in Exile on Jan 12, 2012 12:22 PM MST up reply actions
What's going on with John Wall?
I haven’t seen the Wizards play this season (just highlights, and do like the new unis) but did go over and look at his stats after Evan mentioned him and, ouch. Saw a report that the team had checked out on Flip Saunders. Is that the story?
Blogging Suns basketball for Bright Side of the Sun from California wine country.
Twitter: @EastBayRaymundo
by East Bay Ray on Jan 12, 2012 12:30 PM MST up reply actions
Great article as usual Ray...
No offense to Evanz, but I personally think we have some superior STAT geeks over here as well. Alex can flat bring the pain and have one’s brain smoldering in no time. MMotherwell does a excellent job too .Will, Jim Coughenor. East Bay Ray, 7footer, Omaha and several others (If I left out a name, sue me…) all do a good job as well. Seth may not be as heavily into advanced stats, but I have been all over SBN, there is no greater analytical mind….period.
Bottom line, I think we have the the perfect amount of advanced stats and analysis at BSOTS…We got guys that than cover a strength or a failing stat-wise from so many different angles and provide great analysis to boot. That’s why I keep coming back. Keep up the good work…
STAT may be gone but the Suns will rise....! BTW, If positivity is a crime, I plead guilty by reason of T-Bird...!
There's always more to learn
And if you read Evan’s work, he’s taken it further than anything we’ve done here. Frankly, he sometimes takes it further than I would even want to go but I plan to incorporate more of this into my analysis. It’s a balance between the emotional fan approach and the overload you with data approach, and there’s value in each.
Blogging Suns basketball for Bright Side of the Sun from California wine country.
Twitter: @EastBayRaymundo
by East Bay Ray on Jan 12, 2012 10:02 AM MST up reply actions
I hear you, Ray...and I normally agree with you....
I for one am always down for learning a new trick or two…But I sincerely believe that what makes BSOTS such a good blog is the balance that we’ve already struck between emotionalism and data. It’s what gives us our identity. it’s why we have so many great “characters” on the forum – We all have different ways of presenting our thoughts and ideas and many use stats in differnt ways of doing that.
Maybe I am just old-school, but nary a fan has to have advanced statitics tell him/her that the Suns run so much better with Nash on the floor…It’s intuitive…Breaking down a missed assignment or rebounding issues is stuff we can chew on analysis wise but do we need data for that…?…Comparing back-up point guards and their contributions is stuff that data helps with. Not so sure I need Advanced Statistics to tell me that Garrett Siler belongs in the D-League…
Anyway, it was a great interview you had with EvanZ
STAT may be gone but the Suns will rise....! BTW, If positivity is a crime, I plead guilty by reason of T-Bird...!
I agree with you about the style of BSotS.
I’ve been to GSoM, and while it’s a nice place, it’s not for me.
And you mentioned me in you list, but I rarely go beyond basic stats (mostly their production compared with their efficiency i.e. P+R+A in combination with shooting percentages and turnovers) and most of my analysis is a healthy dose of the eye est. I believe in looking at the stats, then watching to see how those stats were accumulated. What were the circumstances that allowed for those stats to be put up?
I realize this can get me into trouble if I were to enter into a serious debate, but that’s the way I enjoy watching basketball. I’ll probably eventually check out the advanced stats, because it would be really interesting to see how the numbers stack up to my own observations.
Go Suns, Packers, Jays, and Huskers!
Read my thoughts on Creighton University athletics at Creightonian.com
I also edit things at Ridiculous Upside. Check it out.
Just watched Moneyball the other night
Hopefully Michael Redd can be our Scott Hatteberg.
Nice interview Ray.
"The Knicks with the swiss cheese defense.
...Vince Carter likes cheese." -Walt Frazier
I think it is an interesting discuss for bloggers
But I’m not so sure of its applicability. I think we’ve seen instances where the numbers made the decisions, rather than simply being used as tools (DBacks b/f Gibson’s tenure as Manager).
I also think that everyone should agree that basketball cannot set up the same thing in very large numbers. Baseball has 162 games with the batter standing in the same spot and the pitcher standing in the same spot. That’s a pretty large sample size with somewhat minimal variables (at least compared to basketball).
Given the variables in basketball, you almost have to know as much about the assumptions in the equation as the equation itself in order to appreciate the stats for any sort of value or a prediction to guide any decision-making (for coaches and GMs).
I think its greatest value is for defensive players in a man-to-man situation. What was your mark’s shooting percentage? Your mark’s points? You can rate the help defense, too, to some extent.
Free Steve Nash!
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