If you read my articles here on the regular, you may notice I use a wide range of stats in my analysis. Some of these are often referred to as “advanced stats” or “fancystats” and have a lot of taboo and mystery around them. With the new season just around the corner, I figured now would be the best time to provide a beginner’s introduction to these statistics so that anyone curious can get to grips with them for the coming season. So, make sure you bookmark this in your browser for a quick reference when needed.
The first thing you need to remember is that “fancystats” are actually extremely simple. Tremendous amounts of hard work have been done already by the people who developed these metrics, the people who track and post the numbers on their websites and the people who break this stuff down and find new perspectives in their article writing. Thanks to their hard work, all that is left for the average fan to do is usually just read the number charts and articles, or, if you want to get a little bit deeper, do some basic adding and division to work stuff out for yourself. Simple as.
-Possession Metrics-
Corsi
The word “Corsi” often seems to put people off, but it is a very simple concept (“Corsi” is just the surname of the Buffalo Sabres goaltending coach who came up with the metric) which basically means “shot attempt differential”. Shot attempts are: goals, shots on goal, shots that miss the net, and shots that are blocked. It is usually represented as either a percentage, or as a plus/minus rating for either a team as a whole, or for individual players.
Unlike regular shot statistics, a player’s Corsi number refers to the amount of shot attempts by his team, minus the number of shot attempts by the other team while he is on the ice.
The theory among “stats heads” is that the difference between good teams and bad teams is 5v5 puck possession. Successful teams dominate in this respect while unsuccessful teams don’t. The best way to measure puck possession is by seeing whether teams direct more shots at the opposition’s net than the opposition direct at their net during a game, the theory being that you must have control of the puck to take a shot, and the more shots you direct at goal, the more goals you’re gonna score over the course of a season. So, Corsi is a proxy for puck possession.
This also works the same way for individual players. Some players drive puck possession, some get dominated. Theoretically, assembling a team of strong puck possession/Corsi players is likely to result it a high level of success.
For example, say Zach Parise is +7 in Corsi over the course of the game, that means 7 more shots were directed towards the opponents net than were directed towards the Wild net while he was on the ice.
-Here are the different types of Corsi numbers you will see:
-Corsi ON (or “Corsi/60”) = (Total Corsi +/-) x (60 mins) · (The player’s total ice time).
-Corsi OFF = Team’s overall corsi number while a player is off the ice, tabulated in a similar fashion to Corsi ON.
-Corsi REL = Indicates how solid a player’s possession statistics are relative to those of their team-mates. (Corsi ON – Corsi OFF = Corsi REL)
For more on Corsi:
–http://www.habseyesontheprize.com/2013/7/16/4376378/fancy-stat-summer-school-corsi
Fenwick
Fenwick is almost the same as Corsi, the only difference being it does not factor-in blocked shots. It is named after Matt Fenwick, the Calgary Flames blogger who invented it.
Whether you choose to use Fenwick or Corsi is up to you. Both metrics have a very high correlation with team success.
The stat which is considered the have the highest correlation with team success is “Fenwick Close” which is defined as the Fenwick number when the game is within one goal in the first or second period and tied in the third period and overtime. This number is usually reported as a percentage of Fenwick evens that a particular team gets. Thus an average team has a 50% close Fenwick. The reason for this being, when one team has a comfortable lead they often “take their foot off the gas” and play a more defensive system and allow their opponents to control the puck, while attempting to prevent high quality shooting opportunities. When a team is behind in a game they are “playing desperate” in an attempt to tie up the game. They play a much more offensive system where they control the puck and may be susceptible to high quality scoring chances on the counter-attack.
For example, the charts in this article on Eyes On The Prize last season show exactly how strong Fenwick Close teams tend to make the playoffs and the Stanley Cup more often than not. That article is a must-read.
For more on Fenwick:
–http://www.habseyesontheprize.com/2013/7/17/4520794/fancy-stat-summer-school-fenwick
–http://www.pensionplanpuppets.com/2012/7/25/3184137/intro-to-advanced-hockey-statistics-fenwick
–http://www.habseyesontheprize.com/2013/4/4/4178716/why-possession-matters-a-visual-guide-to-fenwick