The Corsi Defined; History and Impact of the Game

With the 2021 Stanley Cup semifinals in full swing, it’s important for NHL fans to understand key statistics that can show them how their favorite team is performing throughout the game.

The Corsi is an advanced hockey statistic that not many may know of, but is useful to know when analyzing teams or even single players. Keep reading to learn a little bit more about what the Corsi is exactly, the history behind the statistic and how it impacts the game we all know and love.

If you are familiar with the concept of plus/minus, the Corsi is easy to understand. Simply defined, the Corsi is an advanced statistic that is used in hockey to measure shot attempt differential while two teams are at even strength play. Shots on goal, missed shots on goal and blocked shot attempts on the opponent’s net minus the number of shot attempts directed at your own net are all included.

The Corsi stat was first introduced to the game around the 2004-05 season. It is named after the person who introduced the concept and brought it to importance, Buffalo Sabres goalie coach Jim Corsi. Corsi was the goaltending coach for the Sabres from 2001 to 2014.

While working with the team, he was searching for a way to measure how much work his goalies were facing during the game. He wanted to measure this because a shot attempt, whether or not it ends up being a goal, requires attention and reaction from a goalie. There was no previous way to measure this, and Corsi set out to change that.

So, how does the Corsi impact the game? The Corsi is greatly influenced by the goaltender’s performance and luck but also has helped to predict a team’s performances and can be repeated. A team can obviously impact the number of shots they take on their opponent’s goal but can’t always control how many shots are taken on their goalie and which ones go in (or out) of the net.

However, the raw Corsi For and Corsi against statistics doesn’t tell a person as much as they would like. From these numbers we can tell whether a team is attempting more shots than they’re allowing on their goal. To find this out, you need to calculate a team’s Corsi For Percentage. You can do this by dividing their number of Corsi For Events by the team’s total number of Corsi Events, both For and Against. If a team has a percentage above 50%, things are going well for them.

Out of the 16 teams that made the 2021 Stanley Cup playoffs this year, 11 teams had a Corsi For Percentage of 50% or higher. For this reason, the Corsi is an important statistic to learn and understand since it can predict your favorite team's success and overall performance.