Wild About Numbers: An Introduction to dCorsi With Wild Defencemen Rankings

Stats-orientated hockey writers are always looking for ways to improve on the advanced stats metrics they currently have at their disposable. While Corsi, Fenwick, PDO etc. have been remarkably successful in predicting future performance, there are still people looking for ways to make them better and develop new metrics.

Steve Burtch, who writes for our good buddies over at Pension Plan Puppets has, with the help of PPP commenter 'Frag', been slowly developing a new metric called dCorsi (Delta Corsi).

Another way of applying context to individual Corsi numbers is by looking at Quality Of Competition, Zone-Starts and Quality Of Teammates. Generally we look at these numbers, maybe on a Player Usage Chart, and make vague assessments like "that player has a very bad Corsi, but he plays really tough minutes so it's understandable" or "that player has a great Corsi but is very sheltered so take that with a pinch of salt".

While these statements aren't false, it would be better if we could take all these different contextual factors along with a player's Corsi and turn it into one number so we could really see which players are under-performing or out-performing the expectations set by the degree of difficulty of their role. This is what dCorsi effectively does. Or at least, that's my understanding of it. I recommend you read Steve's original post about it for a better explanation.

From that post, here's a basic description of how dCorsi is calculated:

Since that original post, Steve has worked-out the updated numbers and last night he posted a link to the Excel spreadsheet on his Twitter account, which I downloaded. So far he has only done the defencemen, setting the cut-off point at 200+ minutes played this season, which left 179 candidates.

This metric isn't perfect, but it should grow and develop over time and for now it's something interesting to look at. Hopefully it is available on sites like ExtraSkater.com in the near future so we can track it during the season, rather than waiting for Steve to compile it every few months. Also, major thanks to Steve for doing all the work he put into this.

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