If you’re familiar with the core statistics you’ll typically see in an NBA box score, there’s one column that isn’t nearly as straight forward as PTS, REBS, ASTS, STLS, and BLKS and that’s PLUS/MINUS. This more advanced stat is represented in a box score as “+/-” and serves an analysis on how a player contributed to the team’s win/loss.
What is Plus/Minus Anyway?
Plus-minus may be the NBA’s first advanced metric. Plus/Minus a real-time report card for players, showing how well the team fares in terms of points scored and point given up when they’re in the game
Plus/Minus calculates the team’s point differential while a player is on the court, providing insights into their contribution to winning, irrespective of conventional stats. This metric particularly benefits players with “intangible value” — those who significantly influence their team’s success even when standard statistics may not reflect their high-level performance. The idea being that if a player has a overwhelmingly positive plus/minus signifies how important they are to their team’s success.
How is Plus/Minus Calculated?
In the NBA, the plus-minus statistic is calculated by tracking the point differential for the minutes that player is on the court. The point differential formula is relatively straightforward.
Player’s Plus-Minus = (Team’s Points Scored When They’re Playing)−(Opponent’s Points Scored When They’re Playing)
This calculation is done for each player during their time on the court. If the team outscores the opponent while a player is playing, their plus-minus is positive. Conversely, if the opponent outscores the team during a player’s time on the court, their plus-minus is negative. The plus-minus metric is valuable for assessing a player’s overall impact on the game, beyond traditional individual statistics in the box score. It provides insights into how well a team performs with a specific player on the court, considering both offensive and defensive contributions.
For example, when Kevin enters the game and helps the team extend the lead, Kevin’s plus-minus goes up. But, if things get a bit shaky and the opponent scores more points than Kevin’s team; Kevin’s plus-minus takes a hit. Plus/Minus is like the heart of the Fortune Coins experience which lies within the Public Lobby
Plus/Minus considers both sides of points scored. Kevin enters the game and plays with the same four teammates. For those 5 minutes they’re together, that lineup manages to stop their opponents from scoring 14 of the 17 possessions, as long as Kevin’s team scores at a higher slip; that strong defense should contribute to Kevin’s overall plus/minus for that game (and the season).
While plus/minus is not the end all, it’s a deeper way to go beyond the typical stats and provide a better understanding of how impactful a player is during the minutes they played in that game.
When Did NBA First Introduce Plus/Minus
The NBA introduced the plus-minus statistic officially in the 2007–2008 season, aiming to offer a more comprehensive view of a player’s impact beyond traditional individual statistics. Before the introduction of plus/minus, player evaluations heavily relied on counting numbers or metrics like points, shooting percentages, rebounds, assists, steals, blocks, and personal fouls.
The advantages of plus-minus become apparent when analyzing players over a substantial number of games and varied circumstances. Elite players consistently exhibit high plus-minus values during their prime, exemplified by LeBron James and Stephen Curry, who both secured league MVP honors during seasons with remarkable plus-minus figures.
However, interpreting plus-minus requires caution. Its game-to-game volatility can be misleading, and additional in-game factors must be considered. For instance, a superstar player’s lower plus-minus on a particular night doesn’t necessarily warrant benching them in favor of someone with a higher plus-minus in that game. Who that player is playing with matters.
For example, 10 games into the 2023-24 season Kentavious Caldwell-Pope has the third highest plus/minus behind Jayson Tatum and Nikola Jokic. Should that be interpreted that KCP deserves a max contract? No, but it does signify that KCP is a player that ultimately contributes to winning (and that he fits quite well alongside Jokic).
Plus/Minus also fails to factor in the the level of competition each player faces — a superstar typically contends with the opposing team’s best players, while a bench player faces substitutes. While plus-minus proves effective in various scenarios and stands strong on the first couple levels of analysis, its interpretation requires a nuanced understanding of the specific in-game factors influencing a player’s impact.