Plus/minus (+/-) in basketball

Plus/minus (+/-) is the score difference while a player is on the floor. Take the points the team scored during that player's minutes and subtract the points the other team scored. The NBA's stats glossary defines it as "the point differential when a player or team is on the floor". The FIBA Statisticians' Manual calls it the team's net points while the player was on the court.

The formula

+/- = team points scored while on the floor − opponent points scored while on the floor

A player who is on the court while their team scores 18 and the other team scores 12 is +6. A player on for a stretch the team loses 4 to 10 is −6.

How it is counted

At every score, by either team, each of the five players on your floor gets the points added or taken away:

• Your team scores a three: all five on the floor get +3.
• The other team makes a free throw: all five get −1.
• Players on the bench don't change.

A quick check: add up the +/- of everyone on one team and you get five times the final margin. In a game won by 5, the team's plus/minus column adds up to +25.

What it needs

Plus/minus needs two records, and it is only as good as both:

• Who was on the floor, from the starting five and every substitution. One missed sub puts the wrong five on the floor until the next one, and every score in between goes to the wrong players.
• Every point by both teams. If you only keep your own team's scoring, every player's number only counts up. That is not plus/minus.

In HoopReads, plus/minus needs Track lineups on, and it only means something with Track opponent on too. With opponent tracking off, the other team's points are never recorded. Then +/- counts only your own points and can't go negative. Turn both on before tip-off if you want a real plus/minus.

“4:32, Carter in for James”

“their 23 hits a three, James answers with a three”

Judgment calls

• Free throws after a sub. A foul is called, then subs come in before the free throws. Whose plus/minus gets those points? Stat systems differ. HoopReads uses the five on the floor when the free throw is shot, not when the foul happened.
• Missed subs. Until a substitution is fixed, the floor is wrong. HoopReads holds plus/minus when a sub would leave four or six players on the floor, and asks you to fix the lineup first.

What it can't tell you

Plus/minus measures what happened while a player was out there. It doesn't measure what that player did. A bench player who only plays with the starters can post a big plus. A good defender stuck with a weak unit can post a minus. It is noisy over one game, especially in short minutes. Read it next to the player's minutes and over several games before you draw conclusions.

See it in a box score

The sample box score shows a full game with a +/- column for one team, and you can check that it adds up. For the other core stats, go back to the basketball stats guide.