Plus-minus stars and disappointments of the NBA season

Plus-minus stars and disappointments of the NBA season

Analytics

Plus-minus stars and disappointments of the NBA season

derrick rose lin

One of the best ways to get a feel for how a player is impacting the game is to look at the on/off-court splits, and seeing whether he is impacting his team’s performance in a positive or negative way when on the floor.

It’s a really simple test that anyone can do, and all the data is publicly available for each team on the NBA.com stats page. If a player is performing in a way that hurts or helps his team that isn’t obvious, the on/off numbers are typically the first place where you’ll find something interesting – if there’s anything interesting to be found.

On/off-court splits are just simple plus-minus statistics and contain a ton of what’s called “noise” in the data, since it doesn’t tell who a player is playing with or against and in what situations. This is why interpreting pure plus-minus numbers when a players is on or off the court is in many ways is more art than science, and it’s always a great idea to look at the numbers and then go back to the film and check if there really is something to understand.

There are adjusted plus-minus systems such as ESPN’s RPM – which are fantastic over longer time periods at telling how a player improved or worsened a team – that are meant to adjust to variables such as teammates and opponent skill level, but due to the mathematics involved, it’s quite difficult to get reliable results quickly. And over shorter periods of time, it’s often better to “try and figure it out from the raw numbers yourself” – as it were.

Typically, when you look at the on/off statistics, every now and then there are players who just jump out will surprise even the most avid NBA watchers with how good or bad their team is with them on the court. It’s obvious that Stephen Curry, Kawhi Leonard and LeBron James are standout performers, but more often than not you’ll actually find a role player leading the team in the point differential.

kyle korver

Players such as Kyle Korver and Tyson Chandler have often been these types of “on/off stars” in their respective careers. Neither has been the best player, but both have been the kind of supporting players who just make everything work, and their teams seem to just “click” around them. When the defense is scrambling, it always feels like Korver is taking that open three-pointer. Chandler was the defensive anchor of a championship team with Dallas, and when the defense broke down, Chandler was rolling to the rim for morale breaking alley-oop dunks.

In the two tables below, I’ve listed the players whose numbers just pop-out on the screen when you see them this season – first the stars and then the disappointments. In the stars category, I’ve tried not to include star players who obviously make their team better, and in the disappointments I’ve tried to include bigger names, or just guys who couldn’t keep themselves off the list.

For reference, an average .500 team usually has a net rating of around zero, while a 50-win team is somewhere around and above +4.0 in net rating, and +10.0 is a historically good team. A 30-win team is typically a -4.0, and the worst team in the league will hover around -10.0 in net rating.

STARS

*  Notable mentions: Wesley Matthews, Rudy Gobert, Kristaps Porzingis, Chris Bosh and Tiago Splitter

Every NBA team would love to have a prototypical 3-and-D wing that can hit outside shots at a high rate, defend multiple positions, switch assignments and doesn’t need the ball to be successful – an important skill in the modern NBA, where ballhandling is often dominated by point guards. Every year some of these players are the most underappreciated role players, and this season Jae Crowder is the one you’d point to as being the perfect example. The Celtics did a great job with a five-year, $35 million deal that looks like it’s going to be a bargain, and the contract runs straight through the entire prime of Crowder’s career.

Marcus Morris and Al-Farouq Aminu are examples of players who, despite three-point shooting that can come and go, are versatile enough to guard power forwards giving their teams’ positional versatility to battle both in big and small lineups. Also, the Bulls should be encouraged that the team has played well with Tony Snell this year, and Snell has the mix of physical tools and shooting to become the next breakout 3-and-D star.

tony snell

The Orlando Magic have been fantastic this season with Channing Frye, outscoring opponents by 7.8 points per 100 possessions with him on the floor. Many thought Frye was out of place with such a young and talented roster, but his shooting helps spread the floor for Victor Oladipo and Elfrid Payton to get into the lane and make plays. With Frye off the court, the Magic have been outscored 3.7 points per 100 possessions, equaling the difference in net rating between the Cavaliers and the Suns.

Omri Casspi has been on fire this season, shooting 47.7 percent from the three-point line and he’s a very good complement next to DeMarcus Cousins on the frontcourt in small-ball lineups, since it makes it harder to double Cousins in the post.

Since the Kevin Love era in Minnesota, Ricky Rubio has always been a plus-minus star. Known for his flashy passes, it’s actually Rubio’s defense that makes the biggest difference. Rubio has been the NBA’s most underrated defender for a while now. He’s a pest in passing lanes and incredible off the ball denying the ball from his man. He’s also big and gets over screens to contest shots and overall a really smart team defender. The Timberwolves allow just 98.6 points per 100 possessions with Rubio on the court, equaling the the Pacers’ defense this season. When Rubio sits, the Timberwolves allow 109.4 points, which is worse than the 30th ranked Lakers defensively.

DISAPPOINTMENTS

* Notable mentions: PJ Hairston, Dwyane Wade, Shabazz Muhammad, Kyle Singler, Kobe Bryant and Kosta Koufos

You may have noticed Garrett Temple on the better list, and Gary Neal among the disappointments. This is probably less due to Temple’s greatness and more so about the fact that the Wizards’ defense has cratered with Neal on the court, allowing 110.6 points per 100 possessions, a number so far beyond what any team typically gives up it’s hard to find a comparison.

Derrick Rose has done an amazing job fighting back from multiple knee surgeries, but this season he hasn’t helped the Bulls at all. It’s very difficult to have a good team when you have a primary ballhandler that’s shooting under 40 percent from the field and below 24 percent from the three-point line taking 2.5 threes per game. Down from his best seasons, when Rose went to the foul line for around 6-7 attempts per game, Rose is attempting just 2.6 free throws per game, a horrendous mark for a player whose main skill is supposed to be getting to the rim.

Even when rookies put up big numbers and seemingly play well, it’s rare that they actually make a positive impact on the court. Jahlil Okafor falls straight into this camp. He struggles defensively and the team has been much better without him, particularly when they play Nerlens Noel by himself. Okafor is averaging 20.0 points per 36 minutes, but hasn’t been good in virtually any other area of the game so far.

Perhaps most disappointing for a long-time fan is too see how poorly Chandler has played. Chandler has been a historically good finisher around the rim, but he’s getting older and struggling to score over size inside.

Chandler can’t get off the ground right now, and at age 33 it’s becoming increasingly unlikely he’ll ever be the same again.

The Hawks are slowly walking into an interesting point guard dilemma, and Dennis Schroeder has publically said he’d like to start. Jeff Teague has played against better competition, skewing his numbers, and Schroeder’s limitations as a shooter would likely be a bigger problem in a starting role. Just by the numbers however, the Hawks have been significantly better with Schroeder on the court, and he’ll be up for an extension next summer, or heading into restricted free agency the summer after that – the same summer Teague hits unrestricted free agency. Though the two have played together, it’s tough to commit big long-term money to two players who play the same position. The Hawks will have choices to make, and it’ll be interesting to see how they decide to play this out.

Mika Honkasalo is an NBA writer, geek, chart maker and most of all fan. He studies computer science and works in software development and business analytics. His writing can be found at Nylon Calculus and Vantage Sports, and you can find him on Twitter @mhonkasalo.

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