Advanced Statistics: for dummies! Corsi

This is the second installment in a series of posts, designed to introduce advanced statistics in hockey to people who don't know about them, or don't understand. You can find the first post 'Advanced Statistics: for dummies! PDO' here. 

Corsi is the next statistic i would like to touch on. This is a puck possession statistic, meaning, if you have a positive Corsi then your team theoretically has control of the puck more then the other team, while you are on the ice.

Corsi is somewhat of a three part stat, you have your Corsi rel, Corsi off and Corsi on. In my opinion Corsi on is the most important of the three because this is the Corsi that the player can control, to a degree. Corsi is calculated by adding up the total amount of goals against, saves for, blocked shots for and missed shots against and subtracting it from the total amount of goals for, saves against, block shots against and missed shots for, while a certain player is on the ice.

What this statistic is saying is that any puck directed at your net is a negative whether it results in a save, a goal, a blocked shot or misses the net entirely, while any save, goal, blocked shot or missed shot directed at the oppositions net is a positive. So, if you're looking at a certain player's Corsi and it is a positive, what you can take away from that is when this player is on the ice the puck is going the right way more often then not, and if this is happening you will generally see good results for this player. From just looking at Corsi on, there is no way of knowing if this certain player is dictating the play, or riding the coattails of good line mates, one way of telling this is by looking at Corsi off.

Lets take a look at Phil Kessel's Corsi:

This chart is saying is that Kessel has a negative Corsi on, and while that is not a good thing, look at the teams Corsi when he is off the ice, it's over three times worse. This is saying that while the Leafs aren't great when Kessel is on the ice at controlling the play, they are even worse when he is off the ice. This brings me to Corsi rel. Corsi rel is a good way of comparing players to their teammates, as you can see it is the difference between Corsi on and Corsi off, showing how much better or worse the team is with said player. In this category Kessel is in the positive, this is, marginally, a good thing, as it means he is directing shots at the opposing net better then most of his teammates.

Something you should know is that Corsi is something that should be looked at within the same team. You cannot look at Kessel's Corsi (-1.05) and D. Sedin's Corsi (20.54) and compare the two, as they are on different teams with different line mates, and have faced different competition. It is not a perfect stat but it really helps show you some things that you may not have realized yet about a player and how dominant they are, or aren't while on the ice.

Corsi can be tracked at www.behindthenet.ca . I encourage you to go check out your favorite team, and favorite players and see how they stack up against their teammates.

Follow me on twitter at @phoking_awesome and as always, throw any questions in the comment section.