How much do NBA coaches matter?

Posted by on August 5th, 1:12 am

To what degree does Alvin Gentry impact the Suns? (AP Photo/Mark J. Terrill)

To what degree does Alvin Gentry impact the Suns? (AP Photo/Mark J. Terrill)

With a record 11 championships to his credit, it’s easy to argue that Phil Jackson is the greatest coach in NBA history.

Then again it would be hard not to rack up the rings coaching Michael Jordan, Scottie Pippen, Kobe Bryant, Shaquille O’Neal and Pau Gasol.

That’s not to take away from Jackson’s greatness as a coach — few coaches in league history could so adeptly manage all those personalities — but it’s a fact that the NBA is a player’s league and talent often trumps all else.

So that begs the question, how much do coaches matter in the NBA?

Clearly Jackson is a brilliant people manager and with the help of Tex Winter a superb tactician, but how many rings would an average coach have won with Jordan, Pippen, Shaq, Kobe and Gasol?

Jeremias Engelmann’s site “Stats for the NBA” attempts to answer the gist of that question — what kind of a difference do coaches make? — by analyzing how players perform in contrast to expectations with different coaches.

According to Engelmann: “The system gives estimates for players. If the players perform better than their estimates under a certain coach the coach will look good, even if all his players are bad players. A coach can also get a bad rating if his players perform worse than what the system expected them to. Carlisle in Dallas isn’t seen as a good offensive coach by the algorithm even though Dallas is a good offensive team. The system expected them to be better, because they were a better offensive team under other coaches.”

So basically the system compares how players performed under previous and future coaches with how they performed with the coach at hand to see how the coach improved or hurt the team’s respective offense and defense. So just because the Suns’ offense has been elite in recent years and its defense below average doesn’t necessarily mean their coaches will rank thusly since it’s more a comparison to expectations.

Tom Liston from Raptors Republic wrote of the system: “The easiest way to interpret this analysis is this: it attempts to treat the coach as if he is the ’6th man’ on the court. It’s measuring the coach’s influence on those who play, but as Mr. Englemann highlights ‘it can’t tell you whether a coach is good at identifying who is good and who is bad, and if he plays the good players more because of that.’”

On to the Suns, Alvin Gentry ranks 39th and grades out slightly negative overall with his teams playing -0.9 points per 200 possessions worse than expected. His offenses are a bit better than expected (positive 0.5) and defenses worse (-1.3). Keep in mind this data covers the period from 2002 to the present so the tail end of Gentry’s Clippers career is included.

Mike D’Antoni, 25th on this list of 97 coaches, barely impacts his teams at all according to this algorithm, with his squads performing -0.1 points per 200 possessions worse than expected. As one would expect, his offenses were above average (0.8) and defenses below average (-0.9).

Terry Porter not surprisingly ranked 1.0 points per 100 worse on offense but 0.3 better on defense to be 0.7 worse overall. It’s fair to say the Suns’ offense was a bit worse under his guidance than under that of D’Antoni or Gentry.

Going back a bit further, Frank Johnson’s teams were 2.2 worse than expected on offense but 2.0 better on defense.

Of course there are limitations to this analysis. It does not take aging into effect so, as Engelmann noted in an email, Scott Brooks will be credited with the natural improvement of Durant, Westbrook and the rest of the young Thunder players while John Kuester was negatively impacted by the demise of the Pistons.

Similarly a coach who got Shaq the last few years may be unfairly punished while Jackson will get more credit than he deserves just for coaching The Big Diesel during his prime.

However, this algorithm’s main conclusion is that the majority of coaches don’t make a huge difference. Only Tom Thibodeau improves his team by better than two points more than expected (and that should go down once he coaches more than one season), and just 10 coaches make their teams even a point better than expected. More coaches performed worse than expected (only 21 made a positive difference) but only five made their teams more than three points worse than expected.

This analysis does prove in part that coaches make their biggest impact on the defensive end as four of the top five coaches and five of the top eight led defenses more than three points better than expected. Former Suns coach Scott Skiles ranked as the best defensive coach (3.7 better per 100), while Thibodeau, Mike Fratello and Jeff and Stan Van Gundy round out the top five best defensive coaches (which passes the smell test).

It’s also worth nothing that new Suns defensive coach Elston Turner has spent the past decade coaching with Rick Adelman, whose defenses have performed 1.9 points better than expected despite his reputation as an offensive coach.

Tony DiLeo (1.4), Sam Mitchell (1.3) and Kevin McHale (1.2) rate as the best offensive coaches with D’Antoni tied for fourth and Gentry seventh. Former Suns coach Paul Westphal ranks eighth but only nine coaches rank better than 0.1, showing once again coaches can make a bigger impact defensively. UA fans might be interested to know former interim head coach Kevin O’Neill ranks last by a wide margin with an offense losing 4.1 points per 100 possessions than expected.

The great Phil Jackson himself ranks 11th overall (1.2 worse on offense and 2.1 better on defense for a 0.9 net positive), Jerry Sloan was 14th (0.3 worse offense, 0.8 better defense, 0,4 better overall) and Gregg Popovich 32nd (2.8 worse offense, 2.5 better defense, 0.4 worse overall).

Prof. David Berri of Wages of Wins fame has run a similar analysis using Win Score as his evaluation determinant and found that coaches don’t make a very big statistical difference.

Basketball Prospectus’ Kevin Pelton poked some holes in that analysis because there are so many different areas that a coach touches that it would be unfair to evaluate his effectiveness purely by player improvement.

My takeaway is that it is a bit unfair to judge coaches based on how effective their players play under them in comparison to how they play under other coaches because so many variables such as age and teammates cannot naturally be factored in.

As for the Suns it’s clear they have employed superior offensive coaches the past seven years aside from the Porter blip, although so long as we are asking questions it’s fair to ponder how much credit should be given to Steve Nash rather than the head coach for this offensive uptick.

It does appear as if the most effective coaches by this metric are known as defensive gurus, which lends credence to the theory that a coach can be the best possible “sixth man” by implementing a superior defensive game plan, which has not exactly happened in Phoenix this decade.

It would only be fair to conclude by noting there are so many other things that go into a coach’s job that do not factor directly into an analysis like this, such as crunch time execution and the ability to make a critical halftime adjustment and create chemistry.

Like many advanced stats this coaching stat isn’t perfect, especially to those who evaluate coaches based on rings, but it still provides an interesting window into how NBA coaches impact their teams.

Wages of Wins Journal on coaching

After this post was published, Andres Alvarez directed me toward Arturo Galletti’s post on the Wages of Wins Journal analyzing the impact of coaches.

Galletti graphed minutes per game against Wins Produced per 48 minutes for every player season since 1978 and found that “a player’s actual playing ability only accounts for less than a third of the variation we see in playing. What that means is that every time you scream at the television that the wrong guys are getting the playing time, there’s a good chance you are correct.”

As Alvarez cleared up for me on Twitter, this means a player’s ability (as seen through WP48) only explains one-third of minute allocation with the other two-thirds being “who knows.”

The “Stats for the NBA” coaching stat does not take into account who the coach plays, but this is clearly a major area in which coaches should be judged as it’s perhaps the biggest way they impact a game.

Galletti concludes by analyzing how playing times correlates with WP48, and Doug Collins won by a landslide last season with a 84.7 percent correlation. Gentry ranked 17th with a 38.9 percent correlation in part because of how much he played Vince Carter, Robin Lopez and Channing Frye, who puts up weak WP48 numbers.

Michael Schwartz founded ValleyoftheSuns in October 2008 and is the owner/editor emeritus of the site. He is currently working toward his MBA in sports business at San Diego State University.

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Tags: Alvin Gentry · Mike D'Antoni · Phoenix Suns · Phoenix Suns Analysis

5 responses so far ↓

  • 1 Steve // Aug 5, 2011 at 8:43 am

    I think NBA coaches affect the game less than the coaches of any other professional sports league except soccer. NBA players just go out there and do their thing, especially in today’s game. It’s not about fundamentals. It’s not about set plays, and it most certainly isn’t about teamwork. The NBA really isn’t a thinking man’s game any more (if it ever truly was). It’s just about seeing who’s quicker, stronger, or the better shooter. RARELY do we see a team that gets the concept of playing like a team the way that the Spurs have for the past decade and the Mavs did last year (and even still, they’re most scripted offenses, not really sets).

  • 2 EBJM // Aug 6, 2011 at 7:59 am

    First off I think that guy who wrote program has too much idle time on his hands. Did he really need to write a program to support what everybody all ready thought?

    Now to Steve. I guess you simply aren’t a basketball fan or have ever played the game. Today’s players just go out and do whatever they please? It isn’t about fundamentals?

    I can think of a couple of players where that would hold true. Carmelo Anthony is one of them. George Karl was happy not to have to design his games around him anymore.

    Allen Iverson was another.

    But that is hardly the status quo. Even the Heat tried to play as a team but Bosh is a bad fit and they don’t have much talent after James and Wade.

    So basketball was never truly a thinking man’s game? When you a player described as having a low basketball I.Q. those are the ones who aren’t thinking because they do not know how the game is played.. Now I know you have never played the game. Played properly you would never stop thinking. I’m not even going to waste my time explaining.

    Scripted offenses not sets? A set is a scripted offense, specifically a play designed to begin from a standstill after a stoppage in play.

    Teams never have run sets throughout an entire game. It just isn’t possible. They run SYSTEMS. Tex Winters is famous for the Triangle system. Almost every other coach uses the Princeton or variations of it. There are also Motion offenses and Read and React. D’Antoni with his SSOL.

    No fundamentals? A player must have basic fundamentals to even play the game. The ones lacking don’t get off the bench. Amare was or is lacking in some fundamentals but because he played with Nash and could catch the ball and dunk, he could get away without being a complete player.

    RARELY do I see such a clueless post.

  • 3 Steve // Aug 6, 2011 at 12:00 pm

    Rarely do you see any posts because you haven’t been around. I wouldn’t address your post if you hadn’t taken needless shots, but since you did, I’ll break down what you said point by point:

    1. “I guess you simply aren’t a basketball fan or have ever played the game. Today’s players just go out and do whatever they please? It isn’t about fundamentals?”

    You don’t know me. Yes. Correct.

    2. “I can think of a couple of players where that would hold true. Carmelo Anthony is one of them. George Karl was happy not to have to design his games around him anymore.”

    Ok, so now you’re working on proving my point… I’m not getting you

    3. “Allen Iverson was another.”

    Still working on my point… are you sure you disagree with me?

    4. “But that is hardly the status quo. Even the Heat tried to play as a team but Bosh is a bad fit and they don’t have much talent after James and Wade.”

    Oh, now you’re starting to argue. Phew, for a second there, I didn’t think we were getting anywhere. The Heat tried to play as a team? Is that was it’s called when you jack up 10 3′s in the last five minutes of a game when you’re up by 15 in the NBA Finals? Would you call isolation after isolation after isolation for either Wade of LeBron “teamwork.” At least two guys on the Heat are always standing, doing nothing (by nothing I mean waiting to fight for position to get the rebound off an ugly contested jumper, or standing behind the three point line waiting for the catch and shoot). The Heat had a system they worked, and I realize it was a system of Spoelstra’s design, so maybe I can’t blame the players as much as I should blame the coaches, but the Miami Heat’s offense was so juvenile that it was virtually nonexistent. They waltzed to the Finals on talent alone, and the only reason no one else in the East could beat them is because they weren’t talented enough. If there were a good TEAM in the East, which there isn’t (except maybe the dying Celtics, who are now too old for their own good and suffered a major chemistry blow late last season to derail any chance they had left), then the Heat would have been beat before they ever made it to the Finals. Did you watch the Heat vs the Bulls? That was the ugliest offensive series I have ever seen in a CF in my life. Ugly ugly ugly basketball. They called it “defense,” but that’s the biggest crock of crap I’ve ever heard in my life. Those teams were milking the clock and chucking up poor, contested shots all series long, or just plain missing wide open shots.

    I’m done on this little bit.

    5. “So basketball was never truly a thinking man’s game? When you a player described as having a low basketball I.Q. those are the ones who aren’t thinking because they do not know how the game is played.. Now I know you have never played the game. Played properly you would never stop thinking. I’m not even going to waste my time explaining.”

    Today’s basketball does not require the same level of thought as games like baseball, football, soccer, DRIVING (not NASCAR, F1 style driving), or especially the CC sports like golf or tennis. You know I haven’t played the game? Ha. Basketball was never the sport I was best at, but I’ve played it more than any other sport because I love it the most. My physical stature doesn’t bode well for my basketball skills, so a player like me has to depend on two things. Fundamentals and IQ. The way that I get by is that I am a good shooter and I am smart with my choices (obviously I am NOWHERE NEAR this level, but you could think of me as the Steve Nash of rec ball. It doesn’t seem like I deserve to be out on the court with those other guys, but somehow I keep getting the job done, and doing it well). What I mean by basketball not being a thinking game is this:

    In hoops, the vast majority of people predetermine their moves before they touch the ball or before they set to action off the ball. “I’m going to drive right when I catch this.” “I’m taking this shot.” “I’m going to drive until I get contact or a layup.” “I’m going to set this backpick then pop.” They predetermine two steps ahead when the game is truly a lot easier when you take what the defense gives you. And you can never convince me this isn’t true. Most basketball players (at the rec level or at the pro level, doesn’t matter) live in a world where their talent outmatches the guy across the court from them, therefore they can do what they want with him. Derrick Rose’s late game efforts against LeBron? He didn’t think about them AT ALL. Every single time Rose tried to get around LeBron, he was by him before he could blink. Every single time Rose actually gave it an effort. So, in late game situations, he settles for contested jumpers against a guy who’s a half-foot taller than him… Does that sound smart? Does that sound like a guy who’s THINKING about the game?

    6. “Scripted offenses not sets? A set is a scripted offense, specifically a play designed to begin from a standstill after a stoppage in play.”

    I think we have an issue of semantics to resolve before I get onto my point. What I mean by “set” is an X’s an O’s play. The play has at least 4 moving parts, with a depth of about 5 passes and at least 3 possible shot opportunities coming off that set. It’s what one might call a “play.” A “scripted offense” is more like an improvised formation, something like an amoeba in football or a form in soccer. There isn’t really a designed play, but the shape itself is supposed to lead to good things happening, spacing, ball movement, sacks, interceptions, whatever is applicable in the given sport. The most typical “scripted offense” I run in basketball is what I call four out (I play with a bunch of shooters and slashers, so this works perfectly for us). Basically, the two baselines and the two elbows extended are manned by shooters who work the ball around the perimeter or into the post (the one in the four out, one in, but it’s just easier to leave the “one in” off). If a perimeter man passes, he either sets a screen on or off the ball, or cuts to the hoop, then everyone in the formation shifts to get it back to its original shape. If the ball goes into the low post, shooters on the near side typically stay where they are and weak side shooters will typically slash or crash toward the hoop. If the ball goes into the high post, the baseline guys slash or crash, while the elbow guys extend or shift to find the open space. That’s the general gist. There are a couple of options in each scenario (and obviously I didn’t cover everything), but it’s “scripted.”

    Scripted offenses work really well for rec ball or high school ball, when people don’t have the time or mental capacity to learn a bunch of sets. It works almost like a set, but require MUCH less thought and the execution is much simpler, but on the flip side, it’s also much easier to defend. Most teams in the NBA, the Suns included, run a scripted offense for the vast majority of their plays. They get into their offense the same way. The Heat tried this in the Finals after they realized Dallas was better, running high screens with Wade and LeBron over and over and over, but in the Heat’s case, it wasn’t even a five man script. It was a three man script, and the basic hope was that one of the two best players alive would bail out Spoelstra and/or all the morons on the team who aren’t smart enough to run sets.

    7. “Teams never have run sets throughout an entire game. It just isn’t possible. They run SYSTEMS. Tex Winters is famous for the Triangle system. Almost every other coach uses the Princeton or variations of it. There are also Motion offenses and Read and React. D’Antoni with his SSOL.”

    You’re right that teams have never run sets exclusively. But in today’s game, they are virtually limited to plays after timeouts or inbounds plays. That’s pretty much it. I’m pretty sure someone making $6M annually who plays a game for a living has the time to learn 48 minutes worth of set offenses (or even 10 minutes worth of set offenses). It’s not PRACTICAL to run a set every time, but it definitely is POSSIBLE. I don’t get mad that NBA players don’t run sets every time, it’s more that they virtually never run sets. The NBA is mostly about two things: isolation and PnR.

    8. “No fundamentals? A player must have basic fundamentals to even play the game. The ones lacking don’t get off the bench. Amare was or is lacking in some fundamentals but because he played with Nash and could catch the ball and dunk, he could get away without being a complete player.”

    You keep asking questions as if you’re not sure what I’m saying. Yes, I said “NO FUNDAMENTALS.” Watch Warrick shoot. Watch Marion shoot. Watch Shaq play at all. Watch Tim Duncan shuffle his feet EVERY time he touches the ball. Watch Bruce Bowen’s defense. Watch LeBron dribble. Watch Wade’s pathetic J and it’s sideways rotation glory. Watch Josh Smith shoot 100 more threes annually than he should. Watch the 300 travels per game that don’t get called. Watch every single guard gain separation by carrying. Watch Jason Richardson not box out Ron Artest. Watch Jason Richardson help off the best three point shooter in the NBA on Christmas Day when we’re up by two. I could write a book about his mishaps alone. Fundamentals are the BASICS of the game. Pivot foots, shooting pockets (btw, watch 80% of the NBA shoot FTs, it’s pathetic), dribbling… things every second grader knows. The NBA isn’t about fundamentals. It’s about ATHLETICISM.

    And you’re truly out of touch with the world of basketball if you actually believe it’s any different than that.

    9. “RARELY do I see such a clueless post.”

    Right back at ya, big guy.

  • 4 Wilson // Aug 8, 2011 at 10:10 pm

    @ Steve: I think I disagree with the sets vs. scripted offence bit.

    Sets are easy to run. They tell you specifically what route to run, when to set a pick, what your first, second and third options are, etc. The hard part is deciding which set to run and that would either be on the coach or the PG.

  • 5 Justin // Aug 12, 2011 at 8:35 pm

    Coaches in the NBA have a very different role than they do at any other level of basketball because they’re no longer coaching skills or fundamentals. Because of this, they aren’t directly responsible for the skill level of their players per se, which in every other level is their primary focus.

    NBA coaches have two responsibilities: to handle personalities, and to game plan. So coaches do matter a lot, because if a coach can’t keep his team together and can’t draw up a play for the winning shot or prepare his team by effectively scouting, he’s a failure. More talented teams will win 90% during the regular season because their simply that: more talented. Coaching comes into play at the end of games, or over a playoff series.

    In the NBA, coaches who can manage their personnel (Phil Jackson) and can use their smarts to game plan (Popovich) give their team the best chance at being successful.

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