The official glossary guide to CanucksArmy’s analytics-focused post game: The Statsies
By Michael Liu
1 year agoAfter writing two Statsies, I’ve come to realize that having to repeat the definition of each advanced stat is probably not the best course of action. If I leave it out, it isn’t conducive to making these articles accessible, while writing out the definition would bog down the flow of the piece.
As such, here’s a list of the advanced stats that we’ll be looking at and their definitions.
Corsi
Corsi is a measure of shot attempt differential while at even-strength play. This statistic includes blocked shots, shots on goal, missed shots, and blocked shot attempts with the opposing team. Corsi attempts to communicate how often a player spends time in the offensive zone vs the defensive zone through the use of shots, thus indicating the puck possession of the team while the player is on ice.
Corsi For (CF) = Shots + Blocks + Misses
Corsi Against (CA) = Shots + Blocks + Misses from the opposing team
Corsi (C) = CF – CA
Corsi For % (CF%) = CF / (CF + CA); A positive CF% would imply that a player is controlling the puck more than he is not, while a negative CF% would communicate the exact opposite.
Corsi Against (CA) = Shots + Blocks + Misses from the opposing team
Corsi (C) = CF – CA
Corsi For % (CF%) = CF / (CF + CA); A positive CF% would imply that a player is controlling the puck more than he is not, while a negative CF% would communicate the exact opposite.
Corsi For % Relative (CF% Rel) = CF% – CF% of the team while the player is off the ice; If a player is making a positive impact, then their CF% Rel should be positive. If a player is making a negative impact, their CF% Rel should be negative.
Corsi Per 60 Minutes at Even Strength (C/60) = (CF – CA) * 60 / TOI
Expected goals
To put it simply, expected goals is the likelihood of an unblocked shot resulting in a goal. This is the best way to measure shot quality with the current play-by-play record keeping that the NHL uses. An algorithm was created to help in calculating these values, which uses the following variables according to MoneyPuck (ranked in order of importance):
- Shot Distance From Net
- Time Since Last Game Event
- Shot Type (Slap, Wrist, Backhand, etc)
- Speed From Previous Event
- Shot Angle
- East-West Location on Ice of Last Event Before the Shot
- If Rebound, difference in shot angle divided by time since last shot
- Last Event That Happened Before the Shot (Faceoff, Hit, etc)
- Other team’s # of skaters on ice
- East-West Location on Ice of Shot
- Man Advantage Situation
- Time since current Powerplay started
- Distance From Previous Event
- North-South Location on Ice of Shot
- Shooting on Empty Net
These numbers are tested by inputting a chunk of values into the algorithm and training it to produce the xG statistic. It’s a helpful gauge to see exactly what sort of shots a team is taking.
Expected goals for (xGF) = The sum of the expected goal values a player or line has generated
Expected goals against (xGA) = The sum of the expected goal values a player or line has conceded to the other team
Expected goals for % (xGF%) = xGF / (xGF+xGA); A positive xGF% suggests a player is generating more scoring opportunities than giving up, while a negative xGF% suggests the opposite.
Expected goals for % Relative (xGF Rel) = xGF% – xGF% of the team while the player is off the ice; A positive xGF% rel suggests a player is making a positive impact when compared to the rest of his team in creating goals.
High Danger Scoring Chances
According to Natural Stat Trick, each shot is assigned a value on this chart. Attempts made from the neutral or defensive zone are excluded.
The yellow areas are given 1 point, the red given 2, and the blue given 3.
Add 1 to this value if the attempt is considered a rush shot or a rebound. A rebound is any attempt made within 3 seconds of another blocked, missed or saved attempt without a stoppage in play in between. A rush shot is any attempt within 4 seconds of any event in the neutral or defensive zone without a stoppage in play in between. Decrease this value by 1 if it was a blocked shot. Any attempt with a score of 2 or higher is considered a scoring chance. (Natural Stat Trick).
SCF – Number of Scoring Chances for the team while that combination of players is on the ice.
SCA – Number of Scoring Chances against the team while that combination of players is on the ice.
SCF% – SCF / (SCF+SCA); Percentage of total Scoring Chances while that combination of players is on the ice.
SCA – Number of Scoring Chances against the team while that combination of players is on the ice.
SCF% – SCF / (SCF+SCA); Percentage of total Scoring Chances while that combination of players is on the ice.
High Danger Scoring Chances (HDSC) – A scoring chance with a value of 3 or higher.
Goals Saved Above Expected
Goals against average and save percentage have long dominated the statistical conversation surrounding goalies, and it’s easy to see why. They’re easily accessible, while being good indicators of a goalie’s performance. However, in recent years goals saved above expected (GSAx) has become possibly a better way of statistically evaluating netminders. The model is based on expected goals models that value shots against differently based on their quality. Thus, it’s a better indicator of how well a goalie performs since it accounts for the different types of shots they will face.
Thus, how this statistic is calculated is simple. The formula boils down to expected goals against minus goals against. It’s a valuable way to isolate and measure the impact of a netminder and what they contribute to a team.
GSAx Per 60 Minutes (GSAx/60) = GSAx * 60 / TOI
That’s most of the stats we’ll be covering for the Statsies, hopefully it was informative. We’ll be sure to link back to this glossary at the start of every Statsies article, and to update this glossary guide if and when we introduce new terminology.
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