Sunday, 13 October 2013

Dan Hamhuis Has a 57% Corsi; May Be Struggling

Pictured: despair. Image via Chris Peters
One of the quickly developing storylines of the still infantile season is the play of Dan Hamhuis. If you're reading this, you probably know that he's failing the eye test in ways that are either hilarious or depressing, depending how much of your life hinges on a game that takes place before the season is even 10% done. Most recently he, Jason Garrison and Roberto Luongo did a thing. They did this thing:

I, uhh, yeah. That happened. Remember, you, valued season ticket holder, Francesco Aquilini paid those three guys a combined $212,976 tonight for that blooper, which really means nothing but I'm sure it'll get someone somewhere fired up if you tell them.

What isn't meaningless is that despite all his perceived struggles, Dan Hamhuis is killing it on possession. At the time of this post, he's sitting at a Corsi% of 56.8%, good for 3rd on the team behind only the Sedins. Yes, his PDO has been awful and he's due for an uptick in that. But, saying "oh you're just perceiving his poor play because Luongo isn't stopping pucks when he's on the ice" isn't really a valid response to criticisms like "he took a miserable interference penalty" or "he turned the puck over and fell down" because it doesn't address the aspects of his game that are being complained about.

So is there some crucial context that we're missing when looking at his Corsi numbers in isolation? Why is Hamhuis crushing puck possession but failing the eye test so mightily? Well, there are a couple of possibilities that I'll sum up in three main points:

  • Hamhuis' most common forward linemates are the Sedins, who are the Canucks' best possession players.
  • When Hamhuis starts a shift, it is more likely to be in the offensive zone with talented offensive players, relative to all other Vancouver Canucks defenders.
  • Consequently, Hamhuis' possession numbers are being inflated by John Tortorella's coaching decisions.

We know that starting a shift in the offensive zone leads to a boost in Corsi% immediately proceeding the faceoff, and we also know that playing with the Sedins will drag up a Corsi% too. Hamhuis leads all Canuck d-men in OZone start%, and is 4th behind Edler, Garrison and Bieksa in quality of competition. He has also started the lowest percentage of his shifts in the defensive zone out of all Canucks defensemen. While he's not being sheltered, he's the closest to it right now.

As a result, it's possible that Hamhuis' possession numbers are simply being inflated by Tortorella's usage of him. Tortorella has put Hamhuis in the best position of any Canuck defender to have strong possession numbers, and his deployment is working. This also would help to explain why Hamhuis' WOWYs look so damn good, as someone playing with Hamhuis is already more likely to be in a position where the Canucks get the next Corsi event, and someone playing apart from Hamhuis is more likely to be buried in the defensive zone. Good WOWYs here would have less to do with Hamhuis and more to do with coaching.

Of course, there's always an element of good old human error when using the eye-test. Since we're all in a frenzy just waiting for a Hamhuis gaffe, we'll definitely notice when he makes a small mistake just like every other NHL player makes from time to time. As a result of our attention, we're more likely to recall times in which Hamhuis struggled in order to better fit our hypothesis of him playing poorly. This is called confirmation bias.

I do suspect that there's a large element of confirmation bias going on in regards to Hamhuis' play, but quoting his Corsi% as evidence that he's not playing poorly misses a ton of context. The bottom line is that Dan Hamhuis should have the best possession numbers of any Canucks defenseman because he's been put in a position to have the best possession numbers of any Canucks defenseman. He may not be struggling as much as you think, but his possession numbers definitely don't tell the whole story.