Plus-Minus: Chart a Player’s Success across the Entire Floor
Nov 01, 2019
4 Min Read
What better way to find a player’s value than examining whether the team wins or loses when they’re on the court? That’s the power of plus-minus.
During a nationally-televised NBA game, ABC’s cameras picked up a conversation between Golden State Warriors coach Steve Kerr and star shooter Stephen Curry, who was in the midst of a poor shooting night.
“That’s your shooting totals. That’s your plus-minus,” Kerr said, while showing Curry a stats sheet. “Alright? So it’s not always tied together. You’re doing great stuff out there. The tempo is so different when you’re out there. Everything you generate for us is so positive. It always shows up here [points to plus-minus]. You’re doing great. Carry on, my son.”
Plus-minus has become a favored stat among basketball coaches because it shows how the team performed when a certain player is on the floor. It goes beyond points, rebounds and other traditional stats to paint a more complete picture of one player’s impact at both ends of the court.
“When it comes down to it, numbers don’t lie,” Ryan Fretz, the head coach of Clyde High School (Ohio), said. “We’re up front about it. We’ll show [the players] the numbers. If you want more playing time, you’ve got to progress here. It gets us looking at the numbers outside of points, rebounds and assists.”
How It Works
Plus-minus qualifies how you’re performing across all 85 feet of the floor—not just the 22 feet around your opponent’s basket. Let’s take a look at the box score from a recent boys basketball state playoff game. Team A below lost by a dozen, despite a respectable 16-point effort from Andrew Abraham in 26 minutes.
Contrast that with Team B here, which is full of plus-minus totals in the double-digits.
Jake States led the team in this stat despite a paltry 2-for-7 night from the floor. How? Because he filled up the stat sheet in other ways in fewer minutes than the team’s leading scorer.
Let’s take a look at it from an NBA viewpoint. Two-time Defensive Player of the Year Rudy Gobert is never going to be mistaken for an offensive dynamo, but his plus-minus figure from a recent season actually fared better than perennial MVP candidate James Harden.
Gobert’s box score stats don’t give him the appearance of a game-changer, but factoring in his defense shows his true value
A player can score 20 points in a game, but if they’re simply hunting shots, not involving others and playing shoddy defense, are they really helping the team?
Plus-minus isn’t a foolproof way to gauge defense, but can shine a light on some less-heralded players.
How Coaches Value It
As coaches tinker with their substitution patterns and how they stagger minutes for their star players, they’re using plus-minus to help separate the rubber from the road.
It’s often particularly resourceful when it comes to evaluating role players off the bench, and what kind of energy they bring to the floor.
“They’re not perfect stats for us, but when you have a bench girl come in and she’s plus-four in five minutes, you go, okay, she’s obviously helping out,” says Lynden Christian (Wash.) girls basketball coach Brady Bomber. “That’s one of our favorite conversations. ‘Okay, this girl was plus-7, why is that? Is it because she’s playing with all the better starters so she’ll get better minutes?’
“But it’s nice for us because we win some games by a lot and others are more competitive, and we can filter out the games that weren’t competitive and just look at those stats for the competitive games.”
It goes the other way, too. Plus-minus data from scout film helps coaches make deeper discoveries. If your opponent is paying attention, that plus-four girl off the bench might be getting more minutes. What are her tendencies? How does she move without the ball? What should you take away from her when she’s on the floor?
How You Can Use It
One of the best ways to use plus-minus is in determining which players should be on the floor together. By looking through the lineup data, you can see which combinations played well together and outscored the opponent.
The plus-minus of lineup data highlights who meshes well. It’s a simple way to help you find your strongest combinations. But like any stat, it isn’t totally flawless.
You should take into account when a player was on the floor (an athlete playing against all reserves might not play as well against the opposing starters) and sample size.
But when combined with other relevant statistics like VPS and the Four Factors, it helps uncover important information that may otherwise slip through the cracks. After all, it’s literally a measure of winning and losing. What’s more valuable than that?
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