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. 

Kyrie Irving: ‘I see you. I see everyone. More than just your physical presence, I see your energy. I feel it. I know it’

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Kyrie Irving has done good lately.

Not just during Celtics games. He gave his jersey and shoes to military members in the crowd, and he recently shared a Thanksgiving dinner with Boston families.

Irving also addressed the event.

Irving, via Nicole Yang of Boston.com:

“I see you,” he said. “I see everyone. More than just your physical presence, I see your energy. I feel it. I know it.”

“I think that the most important thing that I strive to live by is extremely by truth and by consistently giving others the truth, without any judgement, without constraints, without anything extra except the understanding that I see you,” he said. “I have family members who come from knowing energy, and it was passed along to me.”

I can’t get enough of all this stuff.

Report: Derrick Rose away from Cavaliers, evaluating his future in basketball

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When Derrick Rose went AWOL from the Knicks last season for what he called a family issue, rumors swirled that he was contemplating retirement. Rose denied it, but those whispers are reemerging.

Adrian Wojnarowski of ESPN:

Rose has been out with what seemed like a relative minor, for him at least, ankle injury. The 29-year-old could stick in the league for a while thanks to his reputation and ability to attack the rim to create shots for himself. But the guard is a shell of peak form after years of more serious injuries. This isn’t the career anyone expected for him when he was named the youngest MVP ever in 2011.

Before the season, Rose was talking about getting a raise on his next contract. He seemed happy to join a contender and have LeBron James in his corner.

But something is amiss. Hopefully, Rose can find contentment – whether that’s continuing his NBA career or walking away.

Ryan McDonough: Suns want to sign two-way Mike James to standard contract

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Brandon Knight got hurt. Eric Bledsoe got traded.

The Suns made Mike James – a 27-year-old rookie on a two-way contract – their starting point guard.

Though he eventually ceded the role to Tyler Ulis, James – the only player on a two-way contract to start an NBA game – is still a rotation regular. He’s an aggressive defender and possesses plenty of offensive moves.

The problem: Unless demoted to Phoenix’s minor-league affiliate before then, he’ll max out the 45 allowable NBA days for a two-way player Dec. 6.

Suns general manager Ryan McDonough, via Scott Bordow of azcentral:

We’d still like to get him on the 15-man roster and we’re looking at different ways to do that.

The Suns can unilaterally convert James’ two-contract into a standard one-year minimum deal. Both sides could also negotiate a longer contract.

The bigger issue is clearing a roster spot.

Phoenix has the maximum 15 players with standard contracts with no obvious cuts. Derrick Jones Jr. doesn’t play much, but the 20-year-old’s athleticism creates intriguing upside. Second-rounder Davon Reed is hurt, though teams rarely cut bait so quickly.

So, a trade is possible. Greg Monroe never seemed long for Phoenix. Or anyone else could be moved.

If it comes to it, the Suns could send James to the minors to bide time. But they want to play competitive basketball, and he helps. So, expect something else to give within the next couple weeks.

Joel Embiid upgrades himself from 69% to 81%: ‘Shoutout to Jalen Rose’

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A story in three parts:

1. After posting 46-15-7-7 in a win over the Lakers, frequently injured 76ers center Joe Embiid declared himself to be 69%:

2. ESPN analyst Jalen Rose called that joke “unprofessional:”

3. Embiid upgraded his status to 81% with a “shoutout to Jalen Rose:”

In case you didn’t get the joke.