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. 

Stephen Curry starts ridiculous Warriors fast break (VIDEO)

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Golden State is such a thing of beauty to watch in transition.

This play starts when Stephen Curry slides down to help on post defense on Clint Capela, steals the ball, saves it to a teammate and then gets it back when they start the break. James Harden tries to slow Curry down, cutting him off in the backcourt, Curry just whips a 20-foot behind-the-back pass to Andre Iguodala, who lobs it to Leandro Barbosa for the finish.

Houston fought back from 16 down early to make it interesting for a while, but Golden State pulled away late for the 123-110 win. Curry finished with 35 on the night.

Report: Pelicans’ Tyreke Evans out for season due to planned knee surgery

NEW ORLEANS, LA - JANUARY 19: Tyreke Evans #1 of the New Orleans Pelicans shoots the ball during the game against the Minnesota Timberwolves on January 19, 2016 at the Smoothie King Center in New Orleans, Louisiana. 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. Mandatory Copyright Notice: Copyright 2016 NBAE (Photo by Layne Murdoch Jr./NBAE via Getty Images)
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The Pelicans’ just can’t get and stay healthy. Tyreke Evans just can’t stay healthy this season.

Evans — who has averaged 15.2 points and a team-high 6.6 assists per game this season — will be done for the season following planned knee surgery, reports Shams Charania of the Vertical at Yahoo Sports.

The Pelicans had been looking at potential trades for Evans, all of that is dead now. (New Orleans would like to move Eric Gordon, but most other teams are more interested in Ryan Anderson.)

The Pelicans have been 3.2 points per 100 possessions better this season with Evans on the court. However, in recent weeks coach Alvin Gentry has given increasing minutes and increasing responsibilities to Jrue Holiday.

It is possible Gentry keeps Bryce Dejean-Jones starting and bringing Holiday off the bench (as he did last game), just to keep the bench rotations where he wants them. Also, expect Norris Cole to get more run.

None of this matters much, this has been a lost season for the 19-32 Pelicans. They are the current 12 seed, 6.5 games out of the last playoff spot, they are not catching anyone. Don’t be shocked if Anthony Davis is shut down early for the season as well.

John Wall, Wizards ruin Rambis’ Knicks debut with 111-108 win

during their game at Madison Square Garden on February 9, 2016 in New York City.   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.
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NEW YORK (AP) — John Wall had 28 points and 17 assists, Bradley Beal scored 26, and the Washington Wizards beat New York 111-108 on Tuesday night in the Knicks’ first game under Kurt Rambis.

Wall made four free throws in the final 6.6 seconds and the Wizards held on when Langston Galloway‘s 3-pointer at the buzzer was just short.

Carmelo Anthony had 33 points and 13 rebounds, but the Knicks lost their sixth straight in their first game since firing Derek Fisher on Monday. They have dropped 10 of 11 and started Rambis’ era the same way Fisher’s ended, by quickly falling in a huge early hole.

Rookie Kristaps Porzingis scored 20 points, but just two after his 14-point third quarter.

Beal also took a charge against Arron Afflalo when a video replay overturned what had been ruled a blocking foul on a basket with 44 seconds left, a play that could have cut Washington’s lead to two.

Wall then kept the Wizards ahead with his free throws and they won for the third time in nine games. The All-Star made the go-ahead basket midway through the fourth, and later added a pair of jumpers before a 3-pointer that seemed to put it away at 106-96 with about 1:50 left.

The Knicks fired Fisher on Monday and appointed Rambis the interim coach through the remainder of the season. Drafted by the Knicks in the third round in 1980, Rambis said for the second straight day that it’s important for the Knicks to get into the playoffs, but that will take a huge turnaround after the All-Star break.

They allowed 63 first-half points, trying their most this season, after he said they had to toughen up their defense.

Porzingis hit a couple of 3-pointers early in the third, but his signature play came much closer to the basket, when he spun baseline around Jared Dudley and threw down a powerful dunk with Marcin Gortat nearby. That put a buzz in the building as only the rookie can and it stayed there as the Knicks caught up at 83-all to end the period.

But Porzingis was on the bench to start the fourth and the Wizards had just gone ahead for good before he returned.

TIP-INS

Wizards: Washington has won five straight at Madison Square Garden. … Guard Gary Neal missed the game with a sore right leg.

Knicks: Phil Jackson, during an interview with MSG Network, said the chances of a trade before next week’s deadline were “very slim” but that they would be looking. … Reserve forward Lance Thomas returned after missing two games because of a concussion. … F Thanasis Antetokounmpo rejoined Westchester of the NBA Development League after playing two games for the Knicks.

 

Hassan Whiteside ejected for elbowing Boban Marjanovic in face (video)

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Hassan Whiteside defends himself when questions about his maturity early in his career with the Kings arise:

“That was a long time ago,” Whiteside said. “If they want to think about things that happened four, five years ago, that’s up to them.

“I don’t think it’s something that should follow me, but I really don’t know right now. That was years ago. Things didn’t work out in Sacramento. I worked my way to get back here. I could’ve easily gave up and went back home and just chilled. But I put in the work, and I feel like I’m a hard worker or I wouldn’t be here.”

But then he does something like this.