What Is Corsi in Hockey? Shot-Attempt Differential Explained

Corsi in hockey is a count of every shot attempt a team takes and allows while a given player is on the ice — shots on goal, shots that miss, and shots that get blocked all included — used as a stand-in for puck possession. The reasoning runs like this: the NHL does not record how long each team holds the puck, but it logs every shot attempt, and a team that controls play naturally fires more attempts and surrenders fewer. So shot-attempt differential becomes a proxy for who is driving the game. A player whose team out-attempts opponents while he is on the ice is, more often than not, helping his side control the puck.

The formula

Corsi has two raw pieces and one rate stat built from them:

• Corsi For (CF): total shot attempts your team takes while the player is on the ice.
• Corsi Against (CA): total shot attempts the opponent takes during that time.
• Corsi For % (CF%): CF ÷ (CF + CA)

Corsi For % = CF ÷ (CF + CA)

Because two teams are competing for the same attempts, the league-wide average CF% is 50 percent by definition — every attempt for one team is an attempt against another. That fixed midpoint is what makes the stat easy to read: above 50 is good, below 50 is not.

A worked example

Suppose that across a game, while a defenseman is on the ice, his team registers 55 shot attempts and the opponent registers 45.

• Corsi For: 55
• Corsi Against: 45
• Corsi For %: 55 ÷ (55 + 45) = 55 ÷ 100 = 55%

A 55 percent Corsi For is a strong result — his team controlled the shot count decisively during his shifts. Note what is not in this number: it does not matter whether those attempts were dangerous or whether any went in. Corsi is a volume measure of who is generating play, not a quality or scoring measure.

How to read Corsi For %

Corsi For %	Rating
55% and up	Elite, dominant play-driver
52% to 54.9%	Strong
50% to 51.9%	Above break-even
48% to 49.9%	Slightly below average
Below 48%	Being outshot when deployed

A related figure worth knowing is Corsi relative, which compares a player’s on-ice CF% to his team’s CF% when he is on the bench. It strips out how good or bad his team is overall, isolating his individual impact — a useful way to spot a strong player buried on a weak roster.

Why Corsi matters, and where it falls short

Corsi caught on because, over a full season, it predicts future success better than short-term goal totals do. Goals are rare and streaky; shot attempts pile up fast and stabilize quickly, so Corsi gives an early, reliable read on which teams and players are genuinely controlling play before the goals catch up.

Its blind spot is quality. Corsi treats a harmless point shot the same as a slot chance — every attempt counts as one. A team can win the Corsi battle with a barrage of low-danger shots while losing the game to a handful of better chances. That is why modern analysis increasingly pairs Corsi with expected-goals models that weight shots by danger, the same idea behind xG in soccer. And Corsi says nothing about goaltending, which can override any possession edge on a given night.

Read as intended — a long-run indicator of play control, not a scoreboard — Corsi remains a cornerstone of hockey analytics. For the players who combine possession dominance with finishing, the greatest NHL players is stacked with them, and the most goals in NHL history shows what happens when driving play turns into pucks in the net. To see how other sports build “value versus expectation” stats, compare our explainers on EPA in football and true shooting percentage.

Bottom line: Corsi is shot-attempt differential — all attempts for and against — as a possession proxy, with Corsi For % centered on 50 percent, above 52 strong, measuring who controls play rather than who wins the scoreboard.