Plus-Minus in Hockey: How It Is Calculated and What It Misses

In hockey, plus-minus (+/-) is a skater’s on-ice goal differential for the goals that qualify for the statistic.

A player receives:

• +1 when they are on the ice for their team’s even-strength or shorthanded goal.
• −1 when they are on the ice for an opponent’s even-strength or shorthanded goal.
• No change for a power-play goal scored by either team.

Add the pluses and subtract the minuses. A player who has accumulated 18 pluses and 11 minuses has a +7 rating.

The NHL statistical glossary defines plus-minus as team goal differential while a particular player is on the ice, excluding power-play goals for and against but including empty-net situations. It is recorded for skaters, not goaltenders.

Which goals affect plus-minus?

Game event while the player is on the ice	Player’s team scores	Opponent scores
Even-strength goal	+1	−1
Shorthanded goal	+1	−1
Power-play goal	0	0
Empty-net goal in an otherwise qualifying situation	+1	−1

The shorthanded-goal rule creates an important asymmetry. If Team A scores while killing a penalty, Team A’s skaters on the ice earn a plus and Team B’s power-play skaters receive a minus. If Team B instead scores a power-play goal, nobody’s plus-minus changes.

A skater does not need to score or assist to receive a plus. Conversely, a player can score a power-play goal without adding to their plus-minus. The statistic records an on-ice result, not individual point production.

A worked example

Suppose a player begins a game at 0 and is on the ice for these events:

1. Their team scores at five-on-five: +1
2. Their team scores on the power play: no change
3. The opponent scores at five-on-five: −1
4. Their team scores while shorthanded: +1
5. The opponent scores into an empty net at even strength: −1

The final rating is:

(+1) + (−1) + (+1) + (−1) = 0

The power-play goal is absent from the calculation. The empty-net goal counts because the scoring situation otherwise qualifies, even though the player’s team had replaced its goalie with an extra attacker.

What does a +10 or −10 rating mean?

A season rating of +10 means the player’s team scored 10 more qualifying goals than it allowed while that player was on the ice. A −10 means the team allowed 10 more than it scored.

It does not mean the player personally created or prevented 10 goals. Every skater on the ice shares the result, regardless of who made the decisive play. A player can receive a minus after defending well if a teammate turns over the puck or the goalie concedes the goal. The reverse is also true: a player can receive a plus without contributing meaningfully to the scoring play.

Plus-minus therefore answers a limited descriptive question:

What was the qualifying goal differential with this player on the ice?

It does not, by itself, answer:

How much individual value did this player create?

Why plus-minus needs context

Raw plus-minus mixes the player’s performance with several other influences:

• Team strength: Skaters on dominant teams generally have better conditions for accumulating pluses.
• Linemates and defensive partners: Frequent combinations share many of the same on-ice goals.
• Opposition: The final number does not show whether a player faced top scorers or depth lines.
• Deployment: Offensive- and defensive-zone assignments change the conditions in which shifts begin.
• Goaltending and finishing: On-ice save percentage and teammate shooting percentage can lift or depress the result. The NHL glossary identifies both as possible explanations for unexpectedly good or poor plus-minus ratings.
• Ice time: Players with more minutes have more opportunities to accumulate both pluses and minuses.
• Empty-net usage: Skaters deployed while their team is trailing can take minuses on late empty-net goals.

Adjusted plus-minus models were developed to address some of these attribution problems. A 2010 paper used shift data and regression to estimate each player’s even-strength scoring and goal-prevention effect independently of teammates and opponents (Macdonald, 2010). A later model added ridge regression, controlled for shift-start zone and tested goals alongside higher-frequency shot measures; its authors reported smaller error bounds for the shot-based versions because shots provide substantially more observations than goals (Macdonald, 2012). These are different models, not alternate definitions of the official plus-minus statistic.

How to use plus-minus

Treat plus-minus as an initial descriptive signal, not a final player ranking. For a more informative comparison:

1. Compare players in similar roles and over similar spans.
2. Separate five-on-five play from shorthanded and empty-net situations.
3. Use goal differential per 60 minutes if ice time differs substantially, while remembering that a rate does not remove teammate or opponent effects.
4. Check on-ice goals-for share alongside shot-attempt or expected-goal share.
5. Account for teammates, opponents, zone starts and deployment.
6. Be cautious with short samples because goals occur infrequently.

Plus-minus is easy to calculate and useful for describing what happened during a skater’s qualifying minutes. Its central limitation is attribution: the number appears on one player’s stat line, but the goals behind it were produced—and allowed—by everyone on the ice.