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. 

Giannis Antetokounmpo beats Celtics with late-game tip-in, series goes 2-2 (VIDEO)

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It was an exciting finish in Milwaukee on Sunday, where the Bucks took home a win on their home court to level the series against the Boston Celtics, 2-2.

The game came down to the wire, with 2016-17 NBA Rookie of the Year Malcolm Brogdon giving the Bucks the lead after a corner 3-pointer with just 33.5 seconds left. The Celtics responded with a sideline out of bounds play that resulted in Al Horford tying the game with free throws.

On their final possession, the Bucks again went to Brogdon, who missed on a layup driving to the left side of the floor. Luckily, Giannis Antetokounmpo was there to follow with the tip-in with just five seconds left.

Via ESPN:

Boston was unable to convert on a final play, and Milwaukee grabbed the win, 104-102.

Game 5 will be in Boston on Tuesday.

Report: Ime Udoka, Ettore Messina, David Fizdale to interview for Hornets job

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The Charlotte Hornets have a new GM in Mitch Kupchak. Upon taking the helm, Kupchak made short work of firing head coach Steve Clifford.

Now, the Hornets need a new coach and they have quite a few names to choose from.

According to a report from ESPN’s Adrian Wojnarowski, the Hornets will be interviewing current San Antonio Spurs assistants Ime Udoka and Ettore Messina along with former Memphis Grizzlies head coach David Fizdale.

Via Twitter:

All three have extensive coaching experience under their belts. Udoka played in the NBA for seven seasons and has been an assistant coach in San Antonio since 2012.

Messina is a four-time Euroleague champion as a coach, and a two-time winner of the Euroleague Coach of the Year award. He’s coached abroad and in the U.S. since 1989, and he’s been with the Spurs since 2014.

Fizdale coached the Grizzlies for two seasons. Before that he was a longtime assistant coach with the Miami Heat under Erik Spoelstra.

Hornets star Kemba Walker said that who the team chose as GM would influence his decision to re-sign after 2018-19. Walker loved Clifford, so who Charlotte picks as coach could carry significant weight with Walker as well.

LeBron James, Cavaliers hope to even series with Pacers

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INDIANAPOLIS (AP) — LeBron James has been in this playoff position before, just not in the first round.

With Cleveland down 2-1 to the Indiana Pacers in the first round, James was asked if Game 4 in Indianapolis Sunday was a must win.

“It’s the postseason,” said James, who is 10-0 in his career in first-round playoff series with Cleveland and Miami. “Every game is a must win. You want to come in and play well and win no matter what. No matter if you have home-court advantage or if you’re starting on the road, that’s the mindset you have to have. I felt like (Friday) was a must win. We didn’t win, obviously, but it’s the same mindset on Sunday.”

James, who scored 28 points, grabbed 12 rebounds and delivered eight assists in a 92-90 road loss Friday night, rejected what he felt were reporters’ attempts to ask if the other players needed to do more.

“You guys think I’m going to throw my teammates under the bus? I’m not about that,” James said. “Guys just, we have to be better, including myself. Had six turnovers (Friday). I was horrible in the third quarter, couldn’t make a shot. If I had made some better plays in the third quarter, the lead doesn’t skip.”

The Pacers cut a 17-point halftime deficit to six points in the third quarter and finally took their first lead in the fourth quarter.

“We know we all gotta play better as a collective group, no matter who it is,” James said. “We got production to start the game and in the second half there wasn’t much production. We still had a chance to win. We’ve got to regroup and figure how we can be better in Game 4.”

Cleveland coach Tyronn Lue said the Cavaliers were limited because George Hill‘s back “locked up” in the second half. Hill played only nine minutes in the second half, scoring two of his 13 points. Lue used James and Jordan Clarkson rather than backup point guard Jose Calderon in the fourth quarter. If Hill can’t go Sunday, Lue said he will likely start Calderon.

Hill had an MRI on Saturday, but the results weren’t back. He is listed as questionable for Game 4 with back spasms. Hill was hurt during Game 1 when Trevor Booker set a back screen and felt stiffness before Game 2, but played 20 minutes.

For the Pacers, Bojan Bogdanovic was the difference maker, scoring 15 of his team-high 30 points in the fourth quarter. Bogdanovic struggled shooting the first two games of the series.

Bogdanovic, who made 7 of 9 3-pointers, kept his focus after two quick fouls in the first quarter and had to leave briefly in the fourth when he picked up his fifth foul. The seven 3-pointers tied a franchise playoff record, also held by Reggie Miller twice, Chuck Person and Paul George.

“I thought it was going to be another poor performance from myself, but in the second half I started hitting shots and started feeling (much) better and I think a did a great job (Friday night),” the Croatian forward said.

Bogdanovic said he was most pleased with his defense against James.

“Everybody thought before this season that I cannot play defense,” he said. “I don’t say that I am playing great defense, but I am working hard at trying to make it tough for each offensive player that I am guarding.”

Bogdanovic said he tries to push James so he catches the ball far from the basket.

“Against those type of players you just try to stay aggressive on them,” Bogdanovic said.

Pacers coach Nate McMillan was impressed with his ability to produce both ways.

“You’re taking a pounding if you’re on the defensive end of the floor if you’re guarding LeBron,” McMillan said. “But offensively he found some energy. He got some good looks and he knocked them down.”

The Pacers came back to win eight times during the regular season after being down 15 or more points.

“We’ve been resilient,” guard Victor Oladipo said. “We made an adjustment in the second half and it helped us. But it’s only one game; I’m looking forward to Sunday.”

Rumor: Portland coach Terry Stotts could lose job after being swept out of playoffs

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Regular season: Terry Stotts was mentioned as a Coach of the Year candidate after leading the Portland Trail Blazers to 49 wins and the three seed in the West, led by a top 10 defense.

Playoffs: Portland was swept out of the postseason in the first round by Anthony Davis.

The latter part of that is going to lead to some real soul searching and changes coming to the Trail Blazers. That could include Stotts losing his job, reports Marc Stein of the New York Times.

There is plenty of blame to go around for Portland’s quick exit from the postseason, Stein is right that it’s not all on Stott’s shoulders. In fact, I would argue most of it is not.

However, this is the third time in four years Portland is out in the first round, and it leads to the question “what is it about their style that makes them so defendable and beatable in the playoffs?” This is a little like Toronto in recent years, where despite a lot of talent they were predictable and therefore defendable in the postseason. How much of that falls on Stotts vs. the roster he has to coach?

After a period of reflection in Portland, there are going to be changes in the wake of this sweep. Stotts’ job will be part of that discussion, no matter how good a job he did. The question for Blazers management is, if not Stotts then who is next? Who are they getting that’s better?

That said, if Stotts were to be let go he would hand on his feet very quickly.