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. 

Watch Harrison Barnes nab a game-saving steal to put Mavericks past Clippers, 97-95

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DALLAS (AP) Harrison Barnes thrived in a new position on Thursday night, and so did the Mavericks.

Barnes made the go-ahead basket, then stole the ball from Blake Griffin with 3.9 seconds left as Dallas beat the Los Angeles Clippers 97-95.

Mavericks coach Rick Carlisle started a big lineup, with Barnes moving from power forward to small forward.

“I have a little bit more energy from not banging with as many bigs,” Barnes said.

Barnes made a 14-foot jumper with 1:06 remaining for the game’s 11th lead change, making it 96-95. After he stripped Griffin, Wesley Matthews made a free throw with 0.9 seconds to play before J.J. Redick missed a 3-point attempt that would have won it at the buzzer. His shot bounced off the far side of the rim.

“We had a great shot on the last play,” Clippers coach Doc Rivers said. “That was great execution, and it was a 3, would have been a game-winner. Make, miss, we will live with that.”

Griffin scored 21 points, including nine in a row in the fourth quarter, but he missed his last three shots and turned the ball over four times in the game.

“I got to take care of the ball on the last play of the game,” Griffin said, “if you trust me with the last play of the game.”

Dallas expected Griffin to have the ball.

“I have to give credit to our coaching staff,” Barnes said. “They scouted that play well before the game. We knew it was coming to Blake. I just tried to play good defense, and I was in the right spot and the right time.”

The Clippers had their three-game winning streak snapped. Dallas, battling from behind for a playoff berth, had lost four of six.

“I don’t care about the race,” Rivers said. “I care about how we play.”

Seth Curry led Dallas with 23 points. Barnes finished with 21 and Dirk Nowitzki had 14.

The new lineup had Nerlens Noel starting at center and point guard Yogi Ferrell on the bench.

Curry started at point guard and had four assists.

“We’re going to give this a look,” Carlisle said. “It may be the rest of the year, it may not.”

Noel finished with 12 rebounds, two blocked shots and two steals, including one in the final minute.

DeAndre Jordan had 14 points and 18 rebounds for the Clippers. Chris Paul scored 15 points and Austin Rivers had 13.

The Mavericks led by as many as 12 points in the second quarter. But after trailing 44-32, Los Angeles finished the first half on a 22-4 run for a 54-48 halftime lead.

Paul had 13 points in the first half, and Jordan already had a double-double with 10 points and 12 rebounds. Nowitzki and Curry each had 10 points for the Mavericks.

Dallas started the third quarter with a 13-2 run to regain the lead at 61-56. The Mavericks took a 79-77 lead into the fourth quarter.

TIP-INS

Clippers: Redick’s four-point play in the second quarter was the 31st of his career. … The Clippers outrebounded Dallas 25-15 in the first half, but only 20-19 in the second.

Mavericks: Barnes has scored 20-plus points 35 times this season. He totaled 19 games of 20-plus in his first four NBA seasons with Golden State. … Dallas scored 21 points off 17 turnovers, nine in the second half. The Mavericks committed only nine turnovers for eight points.

THE LINEUP

Carlisle seemed pleased with the lineup change.

“We got to look at Curry at point with a really conventional team out there. We got a look at Noel with Dirk and Barnes. We got to see how things would shake out with Barnes at 3.”

THE MIGHTY FALL

Dallas’ J.J. Barea – listed at 6 feet, 185 pounds – was ejected with 5:29 to play in the third quarter after pushing the 6-10, 251-pound Griffin to the floor.

Crew chief Bill Spooner explained the call.

“The contact, in our judgment, was deemed unnecessary and excessive. The contact was to the shoulders and above to the throat. That is deemed as a flagrant penalty two.”

UP NEXT

Clippers: Begin a three-game homestand on Saturday afternoon against Utah.

Mavericks: Play the third game of a four-game homestand vs. Toronto on Saturday.

Marquese Chriss gets up for huge alley-oop off no-look pass vs. Nets (VIDEO)

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Phoenix Suns rookie Marquese Chriss is an athletic big man. During Thursday night’s matchup against the Brooklyn Nets, Chriss got loose behind the defense for an alley-oop off a no-look pass from Tyler Ulis.

The play came about halfway through the first quarter. Ulis was out in transition, and four Nets players committed to the arc with nobody back to guard the rim.

That allowed Chriss to slip past everyone down the left side of the floor for the monster dunk.

Brooklyn beat Phoenix, 126-98. The win was the Nets’ first consecutive win of the season.

Watch DeMar DeRozan score 40 as Raptors beat Heat, 101-84 (VIDEO)

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MIAMI (AP) DeMar DeRozan scored 40 points, marking the first time he’s had that many in consecutive games, and the Toronto Raptors pulled off their 19th double-digit comeback of the season to beat the Miami Heat 101-84 on Thursday night.

DeRozan shot 14 for 25 from the field and 12 for 13 from the line. He needed 38 shots to score 42 against Chicago on Tuesday.

Norman Powell scored 14 and Delon Wright added 13 for Toronto, which never led until midway through the third quarter. The Raptors allowed 33 points in the first quarter, then held Miami to 35 points over the next 27 minutes.

Playing with 13 stitches in his right hand, Hassan Whiteside scored 16 points and grabbed 14 rebounds for Miami. Rodney McGruder and Goran Dragic each had 13 points for the Heat, with Dragic shooting just 5 for 18.

He wasn’t the only Miami player to struggle. The Heat shot only 39 percent, 26 percent from 3-point range. The 84 points tied for Miami’s second-lowest total of the season, and was the first time the Heat failed to reach 90 at home.

The Raptors trailed by 15 points early and eventually led by as many as 17 – a 32-point turnaround. No one in the NBA has been better at pulling off big comebacks than the Raptors, who have come from behind six times since the All-Star break alone.

“It talks about toughness, heart,” Raptors coach Dwane Casey said. “Our give-a-crap level is pretty high, and it’s one of those things where when you count us out, we find a way. My thing is just find five men who are going to play hard.”

Neither team moved in the Eastern Conference playoff standings. Toronto (43-29) remained in the No. 4 spot, pulling within a half-game of No. 3 Washington. Miami (35-37) stayed No. 8, now just a game ahead of No. 9 Chicago and No. 10 Detroit.

TIP-INS

Raptors: DeRozan has two 20-plus-point halves against Miami this season. He had 22 in the second half on Nov. 4, and 24 in the first half of this one. … P.J. Tucker started for Serge Ibaka, who served his one-game suspension for fighting Chicago’s Robin Lopez on Tuesday. … Toronto outrebounded Miami 51-36.

Heat: Wayne Ellington played, one day after the birth of his son. Wayne Ellington III arrived Monday afternoon. … Miami’s three second-quarter field goals were a season-low for any quarter. The previous low was four, done four times. … McGruder reached double figures for only the second time in his last 14 games.

DEROZAN HISTORY

DeRozan became the second player in Toronto history to have a season where he scored 32 or more points at least 20 times. He was an 11-year-old when it last happened – Vince Carter had 28 of those games in 2000-01.

WAITERS UPDATE

Heat guard Dion Waiters missed his third game with a sprained left ankle, and remains in a walking boot. There’s still no timetable for his return, but the Heat said the swelling in his ankle continues to decrease.

UP NEXT

Raptors: Visit Dallas on Saturday. It’s the second time this month Toronto faces Miami and Dallas consecutively.

Heat: Visit Boston on Sunday. Miami is 0-3 against Boston this season, losing by eight, 10 and three points.

JJ Barea goes after Blake Griffin, earns Flagrant 2 and ejection (VIDEO)

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Dallas Mavericks guard JJ Barea didn’t like that Los Angeles Clippers big man was coming to set a screen on him, so he slapped his hand away. Griffin then retaliated with an elbow — which may or may not have connected — and that kicked off a row between the two players that resulted in Barea claiming a Flagrant 2 and an ejection.

It came during the third quarter with Barea at the top of the key and both Griffin and DeAndre Jordan on either side of him.

Here’s how the play looked from multiple angles:

Curious that Griffin wasn’t assessed a foul at all given his own handsy nature. After the game referee Bill Spooner responded to pool reporters by saying that Barea was ejected for his contract above the throat. Meanwhile, Spooner also said that whether Griffin flopped or not was irrelevant.

“It has nothing to do with the merits of the play,” said Spooner.

Meanwhile, the Mavericks beat the Clippers, 97-95.