October 3rd, 2011, 7:35 pm
We like advanced hockey stats, and by advanced, we mean stats that are not in your average box score. Sometimes we forget to define them when we use them in the podcast or in posts, so now we have a glossary to give some quick definitions. Most of these stats can be found at BTN.
Corsi – A similar stat to +/-, Corsi measures all pucks directed towards the net, including missed shots and blocked shots. Corsi counts many more events than +/-, so it’s not nearly as finicky as +/- can be. Like +/-, players on good teams tend to have higher ones, so that’s why some like to look at Corsi Relative.
Corsi/60 (Corsi per 60) – A player’s Corsi, normalized to 60 minutes of ice time.
Corsi Relative (also called Corsi Rel) – A way to compare players that neutralizes team effects, Corsi Rel is a player’s Corsi when they are on the ice versus when they are off. If a player has a Corsi/60 of 5.0 (meaning the team directs 5 more shots towards the opposing net than they surrender when the player is on the ice) but a Corsi/60 of 6.0 when the player is sitting on the bench, the player’s Corsi Rel is -1.0. Corsi Rel is always per 60 minutes of ice time.
ESSV% – A goalie save percentage at even strength. Provides context to overall SV%, because a goalie’s SHSV% (short handed save percentage) is usually much lower, so a goalie’s overall save percentage is partially a result of something the goalie has zero control over – how many penalties are taken. While the league average SV% is around 0.911, the league average ESSV% is around 0.920.
Fenwick – Same as Corsi, but does not count blocked shots. Fenwick is sometime used instead of Corsi because it has been found to correlate to winning percentage better.
Goalie Steal – A stat invented by Mike, indicating when a goalie basically stood on his head and stole the game. A Goalie Steal is when the goalie faced 35 or more shots, and gave up one goal or less.
GVT – Stands for Goals Versus Threshold, this is designed by Tom Awad as a one-size-fits all metric for any player. It attempts to control for team, era, and competition. Similar to Bill James’ Win Shares, a 3 or 4 GVT roughly translates into one win. 0 means the player is replacement-level, i.e. a decent AHL player that is brought up to fill a hole. Roughly, low single digits is a third or fourth line forward or bottom pairing defenseman. High single digits is a great third liner, decent 2nd line, or very good defensemen. Over 10.0 is a top line player or excellent defensemen, and over 20 is All-World for a skater, and top-10 for a goalie. For reference, Patrick Marleau’s GVT for 08-09 through 10-11 was 17.0, 19.8, and 14.0.
PDO – No idea what this stands for, but this is the sum of the team’s save percentage and shooting percentage at even strength. Average is around 99. When applied to a player, it reflects the team’s shooting percentage and the goalie’s save percentage when that player is on the ice. High shooting percentage (and low save percentage) have been shown to be fleeting stats that regress towards the mean (few players have a shooting percentage consistently above the league average, and bad goalies wash out), so a high PDO for a player is generally regarded as a pretty lucky situation, and a low PDO is considered unlucky. In 2010-2011, Kyle Wellwood had the best PDO of any Shark, 1030 (with a .972 save percentage!), which means his +/- and scoring rate was probably inflated by ‘puck luck’.
QualComp – From BTN, the quality of competition metric is a a pro-rated stat for each player, measuring the Rating of the opposition per minute of ice time. Higher means tougher competition, zero is average, and negative means inferior competition.
QoC Corsi Rel – From BTN, a quality of competition metric that uses Corsi Rel rather than Rating. Over 1.000 is stiff competition indeed, and 1.500 is insane Nicklas Lidstrom territory. Less than -1.000 is extremely sheltered (hello, George Parros).
QS – Quality Start, invented by Robert Vollman of Puck Prospectus. Like the baseball pitcher stat, it’s a measure of when the goalie generally played well. A quality start is awarded if a goalie allows two or fewer goals with a save percentage above 0.884, or allows three or more goals with a save percentage above 0.911 (league average).
QS% – Quality Start Percentage, i.e. the number of Quality Starts a goalie has versus total starts. 60% is generally very good, especially over years. Antti Niemi had a QS% of 65.0 in 2010-2011, good for 5th in the league behind Thomas, Luongo, Rinne, and Bobrovsky. Only seven goalies have had an overall QS% over 60 since 2007-08 – Thomas, Nabokov, Brodeur, Luongo, Lundqvist, Miller, and Hiller.
Rating – From BTN, it’s the player’s +/- when they are on the ice versus when they are off. Similar to Corsi Rel, but not quite as significant.
SHSV% – A goalie’s short handed save percentage.
Zone Starts – Zone starts is a metric that measures the percentage of times a player starts his shift in the offensive zone versus the defensive zone. Neutral zone faceoffs are not counted. Coaches choose when and how to use players before face offs, so a very low Zone Starts number (below 45%) indicates the coach thinks the player is very defensively responsible. Players that have a high zone starts number are considered sheltered, because shots (which improves a player’s Corsi number) and goals are much more likely to result when a shift starts in the offensive zone. In 2010-2011, Jamal Mayers had a zone start percentage of 54.8% (and a QoC Corsi Rel of -0.471), making him the most sheltered player on the Sharks. Joe Pavelski, on the other hand, had a Zone Starts percentage of just 44.5%, a QoC Corsi Rel of 0.581, and still had a Corsi Rel of 11.8. Impressive.