Connect with us

NBA

A Primer on the NBA’s Plus-Minus Statistics

Ben Dowsett explains what plus-minus is and how it can be used to better understand each NBA player’s impact.

Published

on

Modern basketball analysis contains a plethora of advanced statistics and metrics to help us better understand and parse what’s going on out there on the floor. We can go beyond simple measures like points, rebounds and assists to contextualize the game more effectively – from metrics like true shooting percentage that help track the value of shots to advances like SportVU data that help us dig into the granular level of every pass, shot and rebound.

Growing in popularity within the analytics community over the last several years has been another metric: Plus-minus. The term sounds simple enough, but what exactly is it? Let’s break it down in simple terms even the casual fan can understand.

What is Plus-Minus?

In its simplest form, plus-minus is exactly what it sounds like – when a given player is on the floor, be it for a single game, group of games or a season, does his team get outscored or does it outscore the opponent? This very simple metric is housed in most common single-game box scores, and is the rawest way of determining what sort of effect a player has on his team (and the opponent) while on the court.

The results of such a simple statistic can often have tons of noise involved, however, and those in the statistical community have derived more advanced measures to help add detail and context. This process, and the resulting outputs, are most commonly referred to as Adjusted Plus-Minus (APM).

There are a number of different well-known types of APM metrics, each of which uses slightly different techniques to reach their final output. The most basic goal is to account for the other players on the floor when establishing a guy’s total, and this can be done by adjusting a number of different variables. The statistician can control for such elements as coaching, opponent, time in between games and more. They can also use longer stretches of prior games to “inform” the model (the process of setting a concrete statistical baseline with which to compare subsequent players). There are also formats known as Statistical Plus-Minus, which include elements of standard box scores as well.

What Can We Learn From Plus-Minus?

The answer here will vary somewhat depending on which version we’re viewing, but the general goal remains to contextualize the effect a player has on his team and opponents while accounting for as many situations and player combinations as possible. Rather than tracking what a player accomplishes individually, the idea is to determine what each individual player’s cumulative contribution has meant to what their team does while they’re on the floor.

Beyond this, the details will depend on the model. ESPN’s Real Plus-Minus, for instance, factors in both teammate and opponent context for each individual player, and also has an element of box score statistics involved – it’s among the more complex measures out there, and generally considered one of the more “accurate,” so far as such a term confirms what we already can glean about players.

Let’s look at a simple example of how this sort of thing can be useful even for the casual observer:

Quantifying a player’s defensive abilities has always been one of the toughest areas within analytics. Anyone with a keen eye and experience can get a good rough idea by watching players, and one can use NBA.com’s advanced on/off court logs to determine that a team tends to suffer defensively when one particular player steps on or off the court. There are a few other tracking services (such as Synergy Sports and SportVU cameras) that can assist us here.

These are helpful things to know, but they’re limited. What if, for instance, a guy has bad on/off numbers which would indicate that he’s a defensive liability, but in reality he simply plays a huge portion of his minutes with at least one other bad defensive player? That’s where APM metrics come in. By aggregating figures neither our brains nor simple on/off measures could ever keep track of over long periods of time, they can do a much better job of separating the true causes of a team’s positive or negative play on an individual level.

Now, none of these metrics are perfect by any means – it’s why there are so many variations favoring slightly different approaches. No stat can track how well a guy contests a shot, or whether he pushes himself to 100 percent to get around every single screen set against him. But because these metrics touch so many individual data points that help smooth out incongruities, the guys who make these sorts of “non-trackable” plays will almost always eventually show through in APM outputs.

Who Are Some Plus-Minus Outliers?

Part of what helps indicate the effectiveness of a metric like Real Plus-Minus is the fact that a look at the top of the rankings typically reveals all the guys we’d think of as the best players in the league. Last season’s top five for RPM, in order, were: Stephen Curry, LeBron James, James Harden, Anthony Davis and Kawhi Leonard – or in other words, the top three MVP vote-getters, the Defensive Player of the Year, and the best under-22 player since LeBron at that age.

That said, each iteration of APM will highlight several outliers on both ends of the spectrum: guys who the models either like or dislike in stark contrast with what consensus opinions of them tend to be.

Last year’s prime example here would be Milwaukee’s Khris Middleton, who finished 10th overall for RPM despite coming into the year as a relatively unknown player. A large factor was the way his impact on the court for the Bucks was consistently felt even when he wasn’t putting up traditional numbers.

His versatility defensively is a huge plus – Middleton’s capability to guard up to four positions in the right situations made him a plug-and-play piece who could fit with plenty of different lineup combinations. In the long run, these elements plus Middleton’s ability to stay within his role on both ends of the floor made him a Plus-Minus All-Star, and there’s no question the rise in prevalence of these measures at the front office level contributed to him receiving a hefty pay day last offseason.

There are several others as well – Kyle Korver has always rated very well, and guys like Draymond Green and Tony Allen can look to APM metrics as some of the greatest representations of their value on the floor. Michael Kidd-Gilchrist is another who sees his defensive contributions accurately reflected even when traditional stats are unable to do so. In general, while we do see examples of big positive outliers offensively, the majority of them tend to come on the defensive end where aggregating counting stats has always been more difficult.

On the other side of the coin, traditional stats have inflated certain players’ reputations to a point that APM metrics disagree with, sometimes strongly. Enes Kanter is one example – he was 45th of 55 centers for total RPM last season, and was dead last among these same 55 for isolated Defensive RPM. And yet, Kanter still managed to ink a gigantic deal in restricted free agency. Carmelo Anthony is another, finishing just 400th of 474 total players last season mainly due to a big negative figure defensively – confirming to many the prevalent opinion that he’s a one-way player and short of a true superstar for that reason.

A word of caution, one that could be applied to any single-number metric out there: This is not an end-all statistic. A simple look at RPM rankings, or those of any other APM derivative, is not a surefire way of determining which players are “better” than others in any sort of concrete sense. These metrics have error margins, and even their creators would acknowledge that there will always be parts of the game they struggle to pick up entirely. They also don’t do a good job at all of telling us why certain guys rate so highly, a determination that can be tough at times.

Still, APM and plus-minus in general have a number of very effective uses. The ability to contextualize the effect a guy is having on his team over the long run, with a keen eye to certain situations or combinations that may be leaning heavily on his overall production, is a valuable one. Plus-minus metrics aren’t going anywhere, and will only become more useful as our best statisticians figure out ways to make them even more reliable and less prone to error.

Ben Dowsett is a Deputy Editor and in-depth basketball analyst based in Salt Lake City. He covers the Jazz on a credentialed basis for Basketball Insiders, and has previously appeared in the Sports Illustrated and TrueHoop Networks. He can be found on Twitter at @Ben_Dowsett.

Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Headlines

Grizzlies trade Jonas Valanciunas to Pelicans for Eric Bledsoe, Steven Adams

Published

on

According to ESPN’s Adrian Wojnarowski and Andrew Lopez, the New Orleans Pelicans are shipping guard Eric Bledsoe, center Steven Adams, the Nos. 10 and 40 picks of the 2021 NBA Draft, and two future first-round picks to the Memphis Grizzlies for center Jonas Valanciunas and the Nos. 17 and 51 picks of this week’s upcoming draft. So, the Pelicans are giving up the Lakers’ 2022 first-round pick. Valanciunas, the 29-year-old veteran center, averaged 17.1 points, 12.5 rebounds, and 1.8 assists per game in 62 games played throughout the 2020-21 season. He also shot 59 percent from the field. The seven-foot Lithuanian also ranks fourth overall in true shooting percentage (.616) among active players. On July 11, 2019, Valanciunas signed a three-year, $45 million contract with the Grizzlies. He is set to earn $4 million next season.

Additionally, in 71 games played last season, Bledsoe averaged 12.2 points, 3.4 rebounds, and 3.8 assists. The six-foot-one guard also shot 42.1 percent from the field in the 2020-21 season. On November 23, 2020, as part of a four-team trade, Bledsoe and Adams were traded to the Pelicans from the Oklahoma City Thunder, along with two future first-round picks and the right to swap two additional first-round picks. Last season, in 71 games played, Bledsoe averaged 12.2 points, 3.4 rebounds, and 3.8 assists. His field goal percentage was 42.1 percent as well. The 11-year veteran is set to earn $18,125,000 in the 2021-22 season. Before he was traded to New Orleans, on March 4, 2019, the guard signed a four-year, $70 million extension. He earned his first All-Defensive second-team selection in the 2019-20 season.

Moreover, in 58 games played last season, Adams averaged 7.6 points, 8.9 rebounds, and 1.9 assists per game. The six-foot-eleven center ranks fifth among active players for effective field goal shooting percentage (.591). The eight-year veteran also ranks third in offensive rebounding percentage, with an active statistic of 14 percent. On November 23, 2020, the same day Adams was traded to the Pelicans, he signed a two-year, $35 million extension. For next season, he is projected to earn $17,073,171. To add to this trade news, the Grizzlies and Pelicans are swapping second-round picks in this year’s draft, too. Referencing NBA.com’s “Consensus Mock Draft” article, with the No. 10 pick of the draft, the Pelicans were originally expected to draft either Josh Giddey or Davion Mitchell at this number. However, plans have now changed.

From ESPN’s Bobby Marks, the trade will not be finalized until August 6th, and this is because of the annual salaries of these said players. Free agency will begin on August 2, 6:00 p.m. (EST). Furthermore, per Spotrac’s 2021-22 NBA salary cap table, next season’s luxury tax threshold is $136,606,000. The team’s current available luxury tax space is $22,555,195. The Pelicans and Grizzlies have a salary cap maximum of $112,414,000. Brandon Ingram, Bledsoe, and Adams had a combined cap percentage of 39.2 percent. Considering that Bledsoe and Adams are traded away, this will clear up $35,198,171 of dead cap space.

Yesterday, CBS Sports reported the news pertaining to Lonzo Ball’s desire to remain in New Orleans. With extra cap space, the team is expected to re-sign the 23-year-old guard. Likewise, for the Grizzlies, the teams has a luxury tax space of $37,019,952. Their current cap space is $8,321,229. As stated before, the transactions have not yet been finalized. The Grizzlies’ outgoing cap is now $14 million, but from the contracts of Adams and Bledsoe, they are bringing in $35,198,171.

Continue Reading

Headlines

NBA Trade Rumors: Jazz considering trade offers for Bojan Bogdanovic, Joe Ingles, Royce O’Neale, and No. 30 pick of the 2021 NBA Draft

Published

on

Per one interesting announcement from Bleacher Report’s Jake Fischer, the Utah Jazz are open to trading forward Bojan Bogdanovic, forward-guard Joe Ingles, small forward Royce O’Neale, and the No. 30 pick of the 2021 NBA Draft. Fischer stated, “The Utah Jazz are known to be one of the few teams actually searching to move playoff-tested talent. Retaining Mike Conley is an offseason priority, sources said, and the Jazz have held numerous discussions with teams around the league about offloading salary to create for Conley in free agency.” Point guard Mike Conley is set to become a free agent this offseason. Though, general manager Justin Zanik will aim to re-sign the 33-year-old guard in the coming weeks. Conley earned $34.5 million in the 2020-21 season.

“League personnel most often mention Joe Ingles as the Jazz wing to watch, and Bojan Bogdanovic and Royce O’Neale are also considered available for trade as Utah narrows its focus towards building a contender around Donovan Mitchel. The Jazz are also open to discuss trading their No. 30 pick, sources said.” In the 2020-21 season, in 72 games played, Bogdanovic averaged 17 points, 3.9 rebounds, and 1.9 assists per game. On May 1, 2021, in the team’s 106-102 victory over the Toronto Raptors, the six-foot-seven Croatian scored a season-high 34 points, shooting 12-for-22, and he finished his performance with four rebounds and four assists as well. On July 7, 2019, he signed a four-year, $73 million contract with the Jazz.

In 67 games played last season, Ingles averaged 12.1 points, 3.6 rebounds, and 4.7 assists per game. The six-foot-eight forward is set to earn $14 million in the 2021-22 season. Plus, among the mentioned players, Royce O’Neale has contributed the least. In 71 games played last season, he averaged seven points, 6.8 rebounds, and 2.5 assists. On January 19, 2020, the forward signed a four-year, $36 million extension with the team. He will earn $8.6 million next season. According to The Athletic, in the team’s seventh workout for draft prospects, they viewed Quentin Grimes, David Duke, Matt Mitchell, and a few other players. In the first round, if the team chooses not to draft any of the players they are holding workouts for, the organization will trade the No. 30 pick.

Just for a reminder, retrieved from Spotrac, the 2021-22 NBA luxury tax threshold is $136,606,000. Utah’s active roster cap is $133,284,695, the maximum cap is $112,414,000, and the current cap space is $72,990,215. Furthermore, center Rudy Gobert currently has the highest guaranteed contract on the team. On December 20, 2020, Gobert signed a five-year, $205 million extension with the organization. Gobert is set to earn $35.3 million in the coming season, whereas Donovan Mitchell will earn $28.1 million. Gobert and Mitchell combined consume 47.6 percent of the team’s salary cap. For the upcoming 2021-22 season, the Jazz have a guaranteed total of $129,719,453. Based on the team’s future outlook, the Jazz will have to make a trade or two in order to retain their star players. This should go without saying.

NBA Analysis Network reported a few days ago that a potential Jazz-Knicks trade target is Bojan Bogdanovic. Greg Patuto proposed the Knicks receiving Bogdanovic, while the Jazz would receive Kevin Knox II, and the Nos. 19 and No. 32 picks of the 2021 NBA Draft. Now, this could still happen at some point during this draft week, but then again, sports bettors and fans alike understand that these news reports could be just rumors. The most intelligent, unforthcoming general managers know not to leave bread crumb trails for the media, especially leading into the offseason. They will do everything necessary to protect their foolproof plans.

Continue Reading

Headlines

Raptors, Pacers, Timberwolves, Kings, and Cavaliers among teams showing interest in Ben Simmons

Published

on

According to Jake Fischer of Bleacher Report, five teams have shown interest in pursuing Ben Simmons from the Philadelphia 76ers. Fischer reported, “Cleveland, Indiana, Minnesota, Sacramento, and Toronto all showed interest in acquiring the runner-up for Defensive Player of the Year.” Furthermore, the teams are wanting Simmons to change position from point guard to forward. “Multiple executives from those teams, when contacted by Bleacher Report, mentioned their excitement at incorporating Simmons as a play-making forward—not at the point guard position he’s played in Philadelphia.” The six-foot-eleven guard averaged 14.3 points, 7.2 rebounds, and 6.9 assists in the 2020-21 NBA season. This might sound fine for a young rookie, but as a five-year player, these aforementioned statistics were career lows.

However, the 25-year-old also earned his third NBA All-Star selection and second All-Defensive first-team selection last season. After a less than mediocre performance in his third postseason of his NBA career, the majority of 76ers’ fans would agree that it’s now time for Simmons to have a change in scenery. With a regular season record of 49-23 (.681), the No. 1 ranked 76ers in the Eastern Conference entered the conference semifinals as favorites over the Atlanta Hawks. Leading into this series, some NBA analysts were predicting Philadelphia to prevail four games to two. The 2016 first overall pick was expected to limit Trae Young in scoring and rally his team from point deficits, but none of this ever manifested.

Pertaining to postseason averages, Simmons had a playoff series-low of 9.9 points and 6.3 rebounds per game in the conference semifinals against the Hawks. This lackluster showing proved to be a more significant downfall for the superstar, considering Simmons had only five points, eight rebounds, and 13 assists in Game 7 versus the Hawks. In the 2019-20 season, he averaged 2.1 steals per game, leading all other players in the league. Moreover, Simmons currently ranks sixth in the NBA for active player triple-doubles (32). With a total of 32 career triple-doubles, he ranks 13th on the all-time list, tied with Clippers’ guard Rajon Rondo.

On July 16, 2019, Simmons signed a five-year, $169.65 million contract extension with the 76ers. He is set to earn $30.5 million in the 2021-22 season. Among these teams interested in Simmons, Cavs’ Kevin Love has the fourth largest contract guarantee of $91.4 million. Love is due to earn $31.3 million next season, and the 13-year veteran’s contract consumes 26 percent of the team’s salary cap. He could be traded this offseason. Timberwolves’ Karl-Anthony Towns has a contract guarantee of $130.8 million. The 25-year-old Wolves center will earn $31.6 million in the upcoming season.

Plus, Kings’ 2017 first-round pick De’Aaron Fox has a guaranteed contract of $171.1 million. Fox will earn $28.1 million next season. To add to that, Raptors’ Pascal Siakim has a contract guarantee of $131.4 million. Not to mention, reported by Yahoo Sports via trade rumors yesterday, the Golden State Warriors are a potential trade partner for Toronto. The Warriors could make a move on Siakim, clearing up space on the Raptors for Simmons. Per Spotrac, the 2021-22 season cap maximum is $112,414,000. In the coming weeks, one of these said five teams might make a substantial trade offer to the 76ers’ organization that they cannot refuse.

Continue Reading

Top Betting Offers

NBA Team Salaries

Insiders On Twitter

NBA On Twitter

Trending Now