
Marek Zidlicky, Jhonas Enroth, and a Corsi Event. Not pictured: a high-quality scoring chance. (Jim McIsaac, Getty Images)
Last week, Cam Charron wrote about the NHL’s counting problem here at Backhand Shelf, bemoaning the secrecy of NHL teams when it comes to advanced statistics. One part in particular, however, caught my eye when he talked about hockey’s “Aha!” moment when it comes to statistics.
There’s a reference in the Friedman piece to Craig MacTavish walking around looking for the “Aha!” moment when it comes to hockey analytics. I don’t think MacTavish has realized that half the hockey world is a step ahead of him in that regard. The “Aha!” moment comes when you realize that shots are a hell of a lot more predictive than goals for determining future events. As soon as you realize that hockey is a game between two teams trying to take shots on goal, I think the rest of it falls into place.
Cam isn’t really wrong, but this is also one of the biggest problems that people seem to have with so-called advanced statistics: they’re almost entirely reliant on counting shots. Corsi and Fenwick are both shot-based statistics that are pretty much the opposite of “advanced.” All they are is adding and subtracting shots. The more shots for your team and the fewer shots against, the better. Outshoot your opponent enough, particularly at the right time of the game (such as when the score is tied or within one goal), and you’ll win a lot more games than you lose.
If this seems like an incredibly simplistic view of hockey, that’s because it is. It’s also a completely inaccurate view of hockey. That isn’t to say that Corsi and Fenwick aren’t useful, because they certainly are. As Cam points out, shot-based analytics have impressive predictive power. But they also are coming at hockey from the completely wrong end.
I believe this is part of the reason why so many people are resistant to shot-based statistics. What matters is winning, winning requires goals, and a high volume of shots does not, strictly speaking, create goals. Shots are a by-product and not a cause.
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