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The Puck Stops Here

Jan Hejda’s +/- And Corsi

Probably the least logical results I have found in this summer’s look at sabermetrics and hockey surround Jan Hejda of the Columbus Blue Jacket.  Hejda was among the Columbus Blue Jackets leaders in ice time with over 22 minutes played per game.  He is not an offensive star as he contributed only 21 points last season.  Most of his value is defensive. 

If we look at the top 20 adjusted +/- ratings from last season, we find Hejda’s +19.4 is good for sixteenth best in the league.  That is a clear sign that he has been a good player.  However, if we look at the worst 20 adjusted Corsi Numbers from last season, we find Hejda’s -155.8 is nineteenth worst in the league.  That suggests he has been a bad player and clearly contradicts his +/-.  How can that be?

It is clear that when Jan Hejda is on the ice, his team outscores their opponents.  It is also clear that his team is outshot significantly in the process.  The logical conclusion is that Hejda forces opponents to take bad shots instead of creating good offensive opportunities.  This is consistent with observation of his play. 

Hejda highlights a problem with Corsi.  It does not distinguish between bad shots and good shots.  A blocked low percentage shot counts the same as a goal.  He is the most significant example of a player in the NHL who has successfully forced lots of bad shots in place of a lesser number of good shots as a defensive strategy.  He is an example that shows that Corsi Numbers of defencemen with little offensive talent should be taken with a grain of salt - especially when they disagree with +/- ratings.

Jan Hejda is a good defenceman.  His +/- shows that he is effective in limiting scoring when he is on the ice.  The fact that he does this by forcing low percentage shots does not hurt his playing level.  His Corsi is misleading.  He is the best example of that in the NHL.  It is reasonable to be skeptical of the Corsi Ratings of other defensive players with low offensive value.  In cases where their Corsi Rating and +/- disagree, the +/- is more likely to be the meaningful one.

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About The Puck Stops Here

imageThe Puck Stops Here was founded during the 2004/05 lockout as a place to rant about hockey. The original site contains over 1000 posts, some of which were also published on FoxSports.com.

Who am I? A diehard hockey fan.

Why am I blogging? I want to.

Why are you reading it? ???

Email: y2kfhl@hotmail.com