from David Staples of The Cult of Hockey at the Edmonton Journal,

The concept of rating hockey players through Corsi, a measure of each player’s shots-at-net plus-minus at even strength, is an excellent one.

In practice, however, using the standard tools available in 2013 for Corsi analysis, employing on-ice shots-at-net numbers to rate NHL players is problematic and can lead to unfair and inaccurate judgments, as NHL general managers will find if they rely too much on this advanced stat metric to make personnel decisions.

Corsi does have its strength. It corrects one of the major problems of the NHL’s official plus-minus system, doing so by tracking not goals, but shots-at-net, a far more common event in a game than goals, which greatly increases Corsi’s sample size and its accuracy . At the same time, however, Corsi fails to fix the other other major problem with official plus-minus, the high percentage of false positive and negatives handed out in on-ice plus-minus systems.

This is a flaw in the way Corsi is generally used right now, but not fatal to the Corsi concept itself, which might one day be coupled with intensive video analysis to provide a superior plus-minus metric.

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