I am taking a departure from my in depth analysis of Jay Feaster’s first two seasons as the Flames' GM to comment on statistical analysis in hockey. Specifically as it pertains to the Calgary Flames.
The reason I am doing this is because I read a post on another site maligning the Wideman signing quoting (so-called) experts who called the Wideman signing the worst UFA signing of the off-season. This assertion was based on Wideman’s Corsi numbers.
Reference to Corsi numbers on the Internet has become more and more prevalent as the knowledge of advanced statistical analysis trickles down from the number crunchers working for NHL teams to the average fans. So what the heck are Corsi numbers?
Corsi is a statistic which can be simply described as a metric that measures shot attempt differential. As an example: In a hypothetical game between the Flames and Oilers, the Flames direct 50 shots at the Oiler’s net. 30 shots hit the net, 10 shots are blocked and 10 shots go wide. The Oilers direct 40 shots at the net. 30 shots hit the net, 5 shots are blocked and 5 shots go wide. The end result is a game in which both teams have 30 shots on net, but because the Flames directed 10 more shots at the net it gives them a Corsi rating of +10. The interpretation might be the Flames outplayed the Oilers, which may or may not be true. An individual’s Corsi stats are simply the differential when that player is on the ice.
Corsi numbers come in different forms, which I won’t go into, but like all stats they are just numbers, and without context, although useful, are certainly not the be-all-and-end-all of player analysis. These stats can be skewed in many ways much like when a player jumps on the ice on a line change and before they are into the play a goal is scored. This player receives a plus or minus depending on which team scores, but really the stat is meaningless because the player had no influence on the play.
There is even an alternative to Corsi called Fenwick which dismisses the shot-blocking variable on the premise that shot-blocking should be omitted because it is a skill and not a random occurrence. Well, as we all know, sometimes it is and sometimes it isn’t.
With the Flames’ advanced analysis tools like PUCKS and Decision Lens, these numbers can be more accurately qualified and evaluated.
Because statistics are completely situational their context is important to get an accurate picture of what they really mean. Using the PUCKS system the Flames can look at each situation that generates a stat on video to provide context and throw out instances which are meaningless because of the situation, or weight them more heavily if they feel it is warranted.
These situational-adjusted numbers can then be plugged into the Decision Lens software for multiple players and weighted to suit the team’s various criteria to help make the decision of which player(s) to acquire.
But these are just numbers and do not take into consideration a player’s individual skills, leadership, character, ability raise his game etc. So there has to be a human component involved in the analysis as well.
In the case of Denis Wideman, he is a well known quantity to John Weisbrod who was with the Bruins during Wideman’s time with the team. So there is significant first hand knowledge of the more human aspects of Wideman and his game.
Whether Wideman will be successful with Calgary and a solid acquisition is yet to be determined, but the decision was well thought out and used the most advanced software and statistics available in the decision making process.
In conclusion: People who don’t think Feaster knows what he is doing, simply don’t know what he is doing.
Factoid: Denis Wideman was selected to represent the Washington Capitals in the 2011-2012 All-star game.
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