Corsi Number

A Corsi number is determined by taking the number of shot attempts at even strength and dividing it by the number of shot attempts by the opponent. Shot attempts are different from shots on goal in that a shot attempt is any shot directed at the net. Shots on goal, shots that miss the goal and blocked shots are added together to get the total shot attempts.

For an individual player, the Corsi number is calculated by taking the number of shot attempts his team gets at even strength while he is on the ice and divides it by the number of shot attempts the opponent gets while he is on the ice. So, it’s like plus-minus, but for shot attempts instead of goals.

A team’s Corsi number takes the number of shot attempts by the team and divides it by the number of shot attempts by its opponent.

The higher the number, the better. In 2013-14, the Stanley Cup Champion Kings had a plus-931 Corsi number (3,888 shot attempts for, 2957 allowed), while the Maple Leafs, who finished sixth in the Atlantic Division, had a negative-1064 (3,259 shot attempts for, 4,323 allowed).

The Corsi number can also be expressed as a percentage that is calculated by taking shot attempts for, and dividing it by shot attempts for and against. In the case of the Kings using the numbers from their championship season, (3,888 / 3888 + 2957), their CF% was 56.8. The Maple Leafs, in that season (3,259 / 3,259 + 4,323), had a CF% of 42.9. Corsi for percentage (CF%) is the most widely-used version of Corsi.

You may also see Corsi numbers that are adjusted for certain game situations, such as when the team is in a close game, or ahead or behind.

Corsi is the best approximation for puck possession, which analytic studies have shown is a great predictor of future success.