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. 

Raptors players say emotions will run high when Dwane Casey returns

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TORONTO (AP) Kyle Lowry and Jonas Valanciunas spent a dozen years between them developing their games under coach Dwane Casey. Valanciunas had never played for any other NBA head coach before this season.

When they welcome Casey and his Detroit Pistons back to Toronto on Wednesday night, the two longest-serving current Raptors know emotions will be running high.

“It’s going to be different, but hey, I’m still going to try to take his head off, the team’s head off,” Lowry said with a laugh.

The Raptors will face Detroit for the first time since Casey was fired, just days after Toronto was ousted from the playoffs by Cleveland for the third consecutive season.

Lowry became a four-time NBA all-star under Casey’s watch, while Valanciunas has grown into a multi-skilled big man. Casey had kind words for both Raptors on the eve of his visit. Lowry got off to a rocky start with Casey when the Raptors acquired the temperamental guard in 2012, but he and Valanciunas returned the compliment.

“(Our relationship) changed a lot,” Lowry said. “It went from a guy who kind of wasn’t trusting in what I did, and me not trusting in what he wanted, and kind of us battling back and forth, to him being like, `Hey listen, I believe in what you can do, you show me what you can do,’ and me saying `All right, if you show me that and I’ve showed you what I can do, I’ll listen to you more and we’ll have a good relationship.”‘

“It turned into a great coach-player relationship. And him having young kids, and me having … they played soccer together, so we created a bond off the court also.”

Nick Nurse, who was promoted to head coach after Casey’s dismissal, insisted he was looking forward to seeing his former boss despite rumors the two were not close.

“My communication with whoever is between me and whoever I’m communicating with, whether it’s between Kyle and me and Kawhi (Leonard) and me or Case and me. . . or whoever,” Nurse told The Canadian Press. “I’ll keep that to myself. I am looking forward to seeing him.”

Nurse characterized his relationship with Casey as “good.”

“We have five years together and a lot of success. A lot of battles and a lot of long hours together, working hard,” Nurse said. “He took a team from relative obscurity or the hinterlands to relevance, and that may be the hardest thing to do in this league. I’m glad I was a part of it for five years. We had a lot of success and I learned a lot from the guy and have a lot of respect for the guy.”

The 51-year-old Nurse said the biggest lesson learned under Casey was professionalism and diligence.

“The seriousness of the day-to-day, the grind and probably most importantly is the work ethic,” Nurse said. “He used to say it to us a lot. He’d put his work ethic up against anybody in the league and he was right in that. The guy always had our staff prepared and our players prepared, he taught me all those things.”

After leading Toronto to a team-record 59 wins and the top seed in the East last year, Casey was also named the NBA’s Coach of the Year – after his firing.

The Raptors have a video tribute planned for the 61-year-old Casey early in the game.

“He did some really good things for the city, for the team. I think everybody respects him,” Valanciunas said. “(But) as a business we’ve got to move on and he (ended) up pretty well, so that is life. Sometimes we’re separating.”

More AP NBA: https://apnews.com/NBA and https://twitter.com/AP-Sports

Steve Kerr jokes after Durant-Draymond spat: ‘I kicked MJ’s ass’

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Golden State Warriors general manager Bob Myers said on Tuesday that Kevin Durant and Draymond Green had not yet spoken after the two had a dust-up during Monday night’s overtime loss to the Los Angeles Clippers.

Green was suspended for one game, apparently for repeatedly calling Durant “bitch” while the two were still on the court with the Clippers. It was testy, and Durant was even seen saying what appeared to be the words, “That’s why I’m out.”

Things didn’t calm down when the Warriors returned to the locker room after the game, and a suspension was issued by the team.

Meanwhile, Warriors coach Steve Kerr said that he felt that the team would be fine. He reiterated that no team he had ever been on had always experienced smooth sailing. Kerr famously got into a scuffle with Michael Jordan in Bulls training camp in 1995.

To that end, Kerr joked on Tuesday that he had, “Kicked MJ’s ass.”

Via Twitter:

Will things be okay in the Bay moving forward? The team has such a strong culture it’s hard to bet against things getting patched up, especially with regard to how the team will play as they seek another championship this season. Remember, Green was one of the guys who recruited Durant to Golden State in the first place, and the two have the same goal.

The real question many have is whether this spat will have an impact on Durant staying with Golden State this offseason. That’s anybody’s guess, seeing as how Durant is nearly impossible to predict.

For now, we just have to wait.

Kevin Durant appears to mouth ‘That’s why I’m out’ after Draymond Green dustup

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Is Kevin Durant leaving the Golden State Warriors? That has been the question on the minds of many NBA fans for some time now, and the big dust-up between Durant and teammate Draymond Green on Monday night has continued to fuel the speculation that the superstar wing might be headed elsewhere.

That was before any of us saw the following video, where Durant appears to mouth the words, “That’s why I’m out” after he and Green had to be separated during their OT loss to the Los Angeles Clippers.

Take a look for yourself and tell me that’s not what it appears Durant is saying in this clip.

Via Twitter:

I’m no professional lip-reader, I just play one here on the internet. But it does seem that Durant said to himself, “That’s why I’m out.”

Meanwhile, Green will serve a one-game suspension and new doubt has been cast on the inevitability of the Warriors sweeping through the rest of this season.

I don’t know where Durant will end up next year, but the journey we’re going to be on until he decides is going to be a bumpy one.

Report: Minnesota tried to talk Jimmy Butler for Bradley Beal trade with Washington, was turned away

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The Washington Wizards have been an absolute train wreck this season, a team where the players’ clearly do not like each other.

The Minnesota Timberwolves started the season as a train wreck, with Jimmy Butler doing his best to burn the franchise down in an effort to get traded.

That led to Minnesota reaching out to Washington with a “want to swap problems” proposal, which was shot down by Washington, reports Marc Stein of the New York Times in his latest newsletter.

Word is the Wolves did try to engage Washington — another team falling well short of expectations — in trade talks for the sharpshooting guard Bradley Beal.

But the Wizards have kept Beal off limits amid their 4-9 start. They would naturally prefer to trade the struggling Otto Porter, or perhaps even John Wall, but both possess hard-to-move contracts.

This follows the buzz around the league — Washington is open to a change, but teams are calling about Bradley Beal but the Wizards know he’s their best player and are not interested in moving him.

John Wall is almost impossible to trade (read ESPN’s Zach Lowe’s primer for details) because his designated veteran max extension kicks in NEXT season, and if he is traded before then there is a 15 percent trade kicker. Otto Porter has been a pretty average player on a max contract, the kind of deal every team is trying to avoid.

Minnesota made it’s move, trading Butler to Philadelphia. The Timberwolves didn’t get better talent-wise with the trade, but they did start to restructure the team around Karl-Anthony Towns (as it should have been for a while now). They made a move, even if it started with a step back.

Washington may be stuck with this roster until at least next summer. Just add it to the list of dysfunctional things in our nation’s capital.