The advanced stats revolution in hockey is still in its early stages, but hasproduced a handful of metrics that help determine a team's or player'seffectiveness in certain situations.
Though they are often referred to as "fancy stats," many of these numbers are derived from simple math. One of the most important ideas with hockey's advanced stats is that puck possession is very important.Thethinking there is that a team is more likely to win if itpossesses the puck longer than itsopponent;its players would, logically,have more opportunities to score while the opponent has fewer opportunities in less time.
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No stats are absolute, but they can help deduce which playersand teams are best at doing the things that lead to wins.
What is a Corsi number?
A Corsi number is determined by taking the number of shot attempts atevenstrength 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'slike 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).
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What does CF% mean?
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 certaingame situations, such as when the team is in a close game, orahead or behind.
Why is the Corsi number important?
Corsi isthe best approximation for puck possession, which analytic studies have shown is a great predictor of future success.
