David Berri on Adjusted Plus/Minus

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Way back in 2006, David Berri, Martin Schmidt, and Stacey Brook came out with a book called The Wages of Wins. It was supposed to be Moneyball for sports other than baseball, but for a lot of people, the book read like Moneyball with a serious chip on its shoulder. In a team game with lots of variables, Berri and his co-authors were confident in their regression-based assertions that  there were 90 players more valuable than Allen Iverson during the season that he won MVP, that scoring was vastly overvalued while rebounding was too often neglected, and Ray Allen had been just as good throughout his career as Kobe Bryant. 

The general feeling among a lot of hard-core basketball fans and analysts was that the Wages of Wins system, which relied only on box-score based statistics, couldn’t possibly accurately capture everything that made a player valuable in a five-on-five game. The logical extreme of that philosophy came in the form of Wayne Winston, the former stat guru for the Dallas Mavericks whose brainchild was adjusted plus/minus, which sought to measure a player’s value without using any box-score statistics whatsoever. As it turned out, he had some even more outlandish conclusions than Berri and co. did. He said that the Knicks should never have traded Tim Thomas, that Lamar Odom was better than Kobe Bryant, and that Kevin Durant wasn’t helping the Thunder win. 
After last weekend’s Sloan stats and analytics conference, David Berri has a short post up on adjusted plus/minus. Here’s the crux of Berri’s argument for box-score bases metrics over adjusted plus/minus:
JC Bradbury and I – in a forthcoming article in the Journal of Sports Economics — report that only 7% of a player’s adjusted plus/minus is explained by what a player did the previous season (oddly enough, unadjusted plus/minus has a stronger – albeit still relatively weak – correlation).  In other words, the correlation coefficient for adjusted plus/minus from season-to-season is below 0.30.   And when we look at players who switch teams – as Songaila did – we fail to find a statistically significant relationship. In contrast, any measure (PERs, Wages of Wins measures, NBA Efficiency, Win Shares, etc…) based on the box score will have a correlation coefficient of at least 0.65, and often these marks are above 0.80. 

Berri makes a solid point. He uses Darius Songalia as a case study for how inconsistent adjusted plus/minus can be, but he could easily have used Kevin Durant, who started the season as a posterchild for how plus/minus based stats could contradict box score metrics but is now an example of how elastic adjusted plus/minus can be from season to season. 

I’m a big believer in using advanced stats to gain knowledge about basketball, but it appears that both Berri and Winston have holes in their metrics. Berri’s box-score based metrics don’t necessarily reflect who was doing what helped his team win the game. For example, let’s say Matt Barnes plays great defense on Kobe for 20 seconds and forces him into a tough fadeaway. Dwight Howard then blocks out Pau Gasol and keeps him from getting to the rebound. The ball caroms off the rim and goes to Vince Carter, who collects the easy rebound. In Berri’s system, only Carter gets credit for doing something right on that play. 
Winston’s system would theoretically give Barnes and Howard most of the credit for the play above. However, the issue is that they could have radically different roles on a different team. With another team, Barnes might not be a starter or a perimeter scorer, but a stretch four who provides energy and outside shooting off the bench without giving much on the defensive end. Thus, he could have a radically different value with a different team. 
Advanced statistics in basketball are wonderful, but they are far from airtight. For the foreseeable future, the best approach with advanced statistics will be to use a number of different metrics and see how they inform each other rather than wait for one perfect formula to reduce contributions to a single integer. 

Charles Oakley plans to attend Knicks game in Cleveland

FILE - In this Jan. 20, 2011 photo, then-Charlotte Bobcats assistant coach and former New York Knicks star Charles Oakley directs players in the first half of an NBA basketball game against the Philadelphia 76ers in Charlotte, N.C.  Oakley was forcefully removed from his seats at Madison Square Garden and arrested after an altercation near team owner James Dolan. Oakley shoved security guards before they pulled him away from his seat behind the baseline during the first quarter of the Knicks' 119-115 loss to the Los Angeles Clippers on Wednesday night, Feb. 8, 2017. (AP Photo/Chuck Burton, File)
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Charles Oakley might not be welcome at Knicks games in New York.

Knicks games in Cleveland? I suspect he’ll get a different reception.

Ian Begley of ESPN:

Charles Oakley plans to attend New York’s road game against the Cleveland Cavaliers on Thursday night, the former Knicks player told ESPN’s Jeff Goodman.

Oakley, a Cleveland native, has grown close with the Cavaliers. LeBron James particularly backed Oakley in his dispute with Knicks owner Jim Dolan.

To be clear, Oakley’s feud is more with Dolan than the Knicks, Oakley’s former team. So, assuming Dolan doesn’t attend tonight’s game, this won’t into the fireworks we saw at the last Knicks game Oakley attended.

It’ll just be a chance for more people outside Dolan’s payroll to embrace Oakley.

Paul George says he was in dark as trade rumors swirled, “thought I would have been in the loop”

NEW ORLEANS, LA - FEBRUARY 18:  Paul George #13 of the Indiana Pacers greets fans prior to practice for the 2017 NBA All-Star Game at the Mercedes-Benz Superdome on February 18, 2017 in New Orleans, Louisiana.  (Photo by Ronald Martinez/Getty Images)
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If your goal over the next few months is to make your star player happy, build a contender around him, and convince him he wants to be here as a free agent in 2018, the Pacers got off to a rocky start Thursday.

George had been linked to the Celtics, while teams such as Denver and Atlanta made runs at him. It was a swirling vortex of rumors with a lot of “will the Pacers pull the trigger or not” intrigue.

What was it like to be in the middle of that? George wouldn’t exactly know, he was learning of things when we were, and he sounded a little ticked when talking about it to the media Thursday.

Damn.

Those rumors you hear about George going to the Lakers as a free agent in 2018 have some real weight behind them, much of the league thinks that could well happen (2018 is a long way off, but other teams that would like to get in the conversation think that’s PG’s intention).

The Pacers need to change his mind, and it sounds like the first step was in the wrong direction.

Hawks trade Mike Scott to Suns

ATLANTA, GA - SEPTEMBER 26:  Mike Scott #32 of the Atlanta Hawks poses during media day on September 26, 2016 in Atlanta, Georgia.  (Photo by Kevin C. Cox/Getty Images)
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The Hawks wanted a stretch four to back up Paul Millsap and likely spend time with Dwight Howard.

Realizing its roster lacked an adequate one, Atlanta traded for Ersan Ilyasova.

The stretch four the Hawks already had — Mike Scott — has barely played this seasonand looked lousy when he has, shooting just 4-for-27 on 3-pointers ((15%).

Hawks release:

The Atlanta Hawks Basketball Club has acquired a protected second-round draft pick from the Phoenix Suns in exchange for Mike Scott, the draft rights to Cenk Akyol and cash considerations, it was announced today by President of Basketball Operations/Head Coach Mike Budenholzer.

Money was the driving force behind this trade.

The Suns can count Scott’s entire salary ($3,333,334) toward the floor while paying only the prorated portion remaining ($941,177). So, Phoenix saves the difference ($2,392,157) and gets whatever cash Atlanta sent.

Presumably, the Hawks included an amount less than they would’ve had to pay just to waive Scott themselves ($3,333,334).

The Suns can undertake a reclamation project on Scott. Or they could just waive him. The 28-year-old looks pretty wayward.

Phoenix also gets Akyol as another nearly valueless piece. The window for Akyol, the No. 59 pick in 2005, to join the NBA is rapidly closing, if it hasn’t already. He’ll turn 30 in April.

Even in the likely event Scott and Akyol amount to nothing for the Suns, they still get the financial benefits. And so do the Hawks.

Magic Johnson’s Lakers trade for point guard: Tyler Ennis from Rockets

LOS ANGELES, CA - OCTOBER 26:  Jordan Clarkson #6 of the Los Angeles Lakers scores on his layup as he is fouled by Tyler Ennis #6 of the Houston Rockets during a 120-114 season opening win at Staples Center on October 26, 2016 in Los Angeles, California.  NOTE TO USER: User expressly acknowledges and agrees that, by downloading and or using this photograph, User is consenting to the terms and conditions of the Getty Images License Agreement.  (Photo by Harry How/Getty Images)
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Has legendary Lakers point guard Magic Johnson found someone to follow in his footsteps?

Almost certainly not.

But, in his second trade with the Rockets since taking over the Lakers’ front office this week, Johnson found a point guard to take a flier on: Tyler Ennis, who was exchanged for Marcelo Huertas.

Adrian Wojnarowski of Yahoo Sports:

The Los Angeles Lakers have acquired guard Tyler Ennis from the Houston Rockets, league sources told The Vertical.

The Lakers sent guard Marcelo Huertas to Houston in exchange for Ennis, sources said. The Rockets will waive Huertas.

Ennis was the No. 18 pick in the 2014 draft. But he has just looked over his head in three NBA seasons with the Suns, Bucks and Rockets. There’s a reason the Lakers got him so cheap. It’s unlikely he’ll stick in the NBA, and D'Angelo Russell is clearly still the franchise point guard.

Still, point guards tend to develop late, and Ennis is just 22. There’s always a chance he’ll rediscover the court vision he displayed at Syracuse.

The Lakers will hope he plays better — just not too much better. Because his fourth-year team-option was declined, they can re-sign him for a starting salary up to just $3,066,713 (what he would’ve earned, with the rookie-scale adjustment under the new Collective Bargaining Agreement, if his option had been exercised).

Also in the final guaranteed year of his contract, Huertas is making $233,880 more than Ennis. That’s not much, but if the Rockets were going to waive Ennis anyway — this trade suggests they were — why not save that money?

The 33-year-old Huertas likely drops out of the NBA. He already fell out of the Lakers’ rotation.

And with that spot open and a little extra money to spend — including more from the K.J. McDaniels trade — Houston can be a player in the post-buyout market as it revs up for a playoff run.