No, plus/minus is not inherently a "bad stat" in the NBA. While it has inherent limitations, it serves as a valuable and informative metric that helps provide context to a player's impact on their team's performance.
Understanding Plus/Minus
Plus/minus, often abbreviated as +/- or BPM (Box Plus/Minus for advanced versions), measures the net point differential for a team when a specific player is on the court during a game. A positive plus/minus means the team outscored its opponent while that player was playing, while a negative plus/minus means the opponent outscored the team.
The Value of Plus/Minus
Despite its simplicity, plus/minus offers unique insights into a player's contributions:
- Revealing Team Impact: A key benefit of plus/minus is its ability to indicate, at least partially, how a player's performance is affecting the team's overall success. It moves beyond individual statistics like points or rebounds to highlight whether a player's presence genuinely contributes to their team winning or losing their minutes.
- Contextualizing Individual Statistics: Plus/minus can serve as a crucial diagnostic tool. For example, if a player consistently scores 20 points per game but their plus/minus frequently runs negative, it might suggest that their scoring, while impressive on paper, isn't translating into a net positive outcome for the team during their time on the court. This prompts a deeper look into other aspects of their game, such as defensive efficiency, shot selection, or playmaking.
- Highlighting Intangibles: Often, players who contribute through defense, screening, off-ball movement, or spacing, but don't fill the box score, can show up positively in plus/minus, reflecting their actual value to the team's success.
Limitations of Plus/Minus
While useful, it's important to understand the limitations of basic plus/minus:
- Team Dependency: A player's plus/minus is heavily influenced by the performance of their teammates and opponents during their time on the floor. A player on a very strong team might have a high plus/minus even if their individual play is average, and vice versa for a player on a weak team.
- Lack of Granularity: It doesn't specify how a player contributed to the point differential. It doesn't differentiate between a player scoring, making a key defensive stop, or simply being on the court during a scoring run by their teammates.
- Small Sample Size Issues: Over a short period, a few fortunate or unfortunate plays can significantly skew a player's plus/minus, making it less reliable until a larger sample of games is collected.
Conclusion
In summary, plus/minus is not a "bad stat," but rather a foundational metric that provides valuable context. It's best used in conjunction with other traditional and advanced statistics to paint a comprehensive picture of a player's effectiveness and impact on the court. It's particularly useful for identifying players whose individual statistical output might not align with their actual contribution to team success.
