The Basics of Plus/Minus
If you've spent any time watching NBA coverage or reading basketball box scores, you've probably noticed the +/- column sitting at the end of a player's stat line. It might show something like +14 or −7, and unlike points or rebounds, it doesn't measure anything a player directly did. So what does it mean?
Plus/minus measures the net point differential while a specific player is on the court. If your team outscores the opposition by 14 points during your minutes, your plus/minus is +14. If the opposition outscores your team by 7 during your time on the floor, it's −7.
How It's Calculated
The formula is simple:
Plus/Minus = Points scored by your team − Points scored by opposition (while you were on court)
It resets to zero at the start of each game and accumulates over a player's playing time within that match. At season level, it's averaged per 100 possessions to allow fair comparison between players with different roles and minutes.
Why It Matters
Traditional stats like points, assists, and rebounds only capture what a player directly contributes. Plus/minus attempts to capture impact — including defensive positioning, spacing, screens, and other contributions that don't show up in a box score.
- A bench player with 4 points but a +18 rating had an enormous impact on the game's flow
- A high scorer with a −10 may have been winning individual battles while the team struggled
- Coaches use plus/minus to identify which line-up combinations work best together
Limitations of the Basic Plus/Minus Stat
Raw plus/minus has well-known weaknesses. It is highly dependent on:
- Teammates — playing alongside elite players will inflate your rating
- Opponents faced — bench units often face weaker opposition
- Sample size — a player with limited minutes can have a wildly skewed rating
For this reason, analysts have developed more sophisticated versions of the stat.
Advanced Plus/Minus Variants
| Metric | What It Does Better |
|---|---|
| Adjusted Plus/Minus (APM) | Controls for the quality of teammates and opponents |
| RAPM (Regularised APM) | Uses statistical regression to reduce noise from small samples |
| RPM (Real Plus/Minus) | ESPN's proprietary version, blending on/off data with box score stats |
| BPM (Box Plus/Minus) | Uses only box score data to estimate impact — no play-by-play required |
Reading Plus/Minus in a Box Score
When you look at a game's box score, each player's plus/minus reflects only their individual contribution to the team's margin during their specific minutes. Two players on the same team can have very different plus/minus figures — one might have been on court during a strong defensive spell, while another played during a difficult second-quarter run.
The Bottom Line
Plus/minus is a useful, quick indicator of a player's impact beyond traditional counting stats. It works best when used alongside other metrics rather than in isolation. For the casual fan, it's a great way to spot which players truly shifted the momentum of a game — even if they didn't light up the score sheet.