Shot suppression and the Canucks

There’s an article up on Progressive Hockey by Jen LC about how important shot suppression is for regular season and playoff success. The post is well worth reading, but the gist is that teams are far more likely to be successful if they suppress shot attempts against (FA60) as well as dominating possession (FF%). The best teams control pace of play as well as puck possession: ‘low event hockey’.

A paragraph near the end of the article should be interesting to Canucks fans:

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2014/2015 League Projections

These predictions aren’t something I take very seriously. I think it’s fun to have preseason impressions of how the season will go, mainly for the end-of-season laughs at how hilariously wrong I was when Edmonton wins the division (maybe in 2022). What I’ve done is take last years 5v5 Fenwick percentages as the basis for my assessment of each team. From there, my main considerations were special teams ability, and whether the team’s shooting and goaltending talent likely differs substantially from league average (ie LA, NJ and FLA have persistent low sh%). Finally, I considered how offseason changes to coaching staff or playing personnel might have helped or hurt each team. This is what I ended up with for the Western Conference, with each team’s FF% from last season in brackets.

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On Alex Edler

I’ve always been an Alex Edler fan. He gets beat up a fair bit for disappearing during games, for being soft, for not playing tough defence and for whatever else, but I’ve always enjoyed watching him play. The last couple years there have been persistent rumours that the Canucks have been shopping him, with some saying he nearly went to Detroit at the 2013 draft. That 2013 draft was just before the 6 year, 30 million dollar extension they signed him to kicked in, and only a year before Edler had put up a 49 point season. So why were they trying to trade him? There are a lot of defencemen that get hammered in the media for being error-prone or weak defenders that fancy stats support as being really good players (Mike Green comes to mind), but Edler doesn’t really fit into that group. He consistently posts a CorsiRel above zero, but doesn’t seem to be a particularly effective play driver. I thought it would be useful to have a look at some context stats, his WOWYs, and to have a look at how he is on special teams.


Canucks team CF%: 51.9
Alex Edler CF%: 52.5
OZFO%: 35.7 (highest of any Canuck D)
TmCF%: 51.9 (second highest of any Canuck D, after Ryan Stanton)
OppCF%: 50 (QoC isn’t particularly impactful, but I included it for interest’s sake)

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Daniel Sedin’s slow decline (or not)

For many Canucks fans it’s been difficult watching Daniel Sedin for the last few seasons. 47 points last year is nothing to sneeze at – second on the team – but it’s hard to watch him out on the ice without remembering his 104 point Art Ross season in 2010/2011. His offensive ability seems to have just dried up since then, and it’s hard to put a finger on why. The most popular theory seems to be that he hasn’t been the same since he was concussed by Duncan Keith near the end of the 2011/2012 season. There is, obviously, a natural decline as a player ages and I think it is pretty hard to say whether the Keith hit could be responsible. Below are his even strength goal and point scoring rates per 60 minutes since 2008/2009.

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Daniel has seen his even strength point and goal scoring rates drop rapidly since the 2009/2010 season. There’s nothing super unusual about this in itself: he is 33 years old and 13 years into his NHL career. There are a couple things that make Daniel’s decline unusual. He isn’t scoring less because he can’t drive play anymore, that’s for sure. When Daniel is on the ice the Canucks are still dominating possession play and scoring far more goals then their opponents – his career rates haven’t really changed.

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It isn’t just the percentages that have stayed the same: the number of shot attempts per 60 minutes the Canucks are generating with Daniel on the ice has been very consistent over the last 6 years. So if Daniel is still driving possession and producing as many shot attempts as ever when he’s on the ice, why doesn’t he get as many points anymore?

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dCorsi and the Canucks: defence

An addendum two weeks after writing: I have a couple thoughts to add on dCorsi and context-adjusted possession stats: Domenic Galamini has worked on a similar project, using Net FF20 to then calculate NetGoals. I definitely recommend reading his writeup and looking at the numbers here. Both of these statistics, while intensely interesting and valuable, need to be considered a bit before being taken to be definitive. Standardizing how contextual factors can be adjusted into possession stats is still in its early days, and will only continue to develop with time. So when we get a strange result (like Alex Edler’s) you have to look at his standalone stats and question at least a little bit whether it feels plausible. That isn’t to say it’s wrong: we have such a long way to go on judging defence people still think Jack Johnson and Andrew Macdonald are good defencemen worth millions upon millions of dollars. It’s just worth considering.

I’ve spent a lot of time thinking about the Canucks defence since I started to dive into the dCorsi data in earnest. What I find so interesting about the Canucks D last year is that even though the Canucks were a top-10 possession team, the “core” of the Canucks D last year fell off a cliff in terms of possession numbers. I think most people around the league have generally agreed that the Canucks have a really solid defence group in Hamhuis, Edler, Bieksa, Tanev, and until recently, Garrison. That group looked shakey in comparison to years past last season, and Garrison’s season was so brutal that they traded him in what mostly amounted to a salary dump. Their possession numbers really did collapse last year: below is a chart of that core group’s average CorsiRel from the previous three seasons compared to last year.

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Every single member of that group posted a worse CorsiRel last season under Tortorella than they had posted over the previous three seasons. This isn’t a fluke or some sort of crazy simultaneous decline of every Canucks defenceman either: Tortorella has had a similar effect on defencemen in the past.

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dCorsi and the Canucks: forwards

Note: for this post to be worth reading you need to have an understanding of what Corsi is. If you’re looking for a resource for learning about Corsi and possession statistics, try this one.

Stephen Burtch of Pension Plan Puppets has been working on a statistic for individual player possession that takes into account outside factors: zone starts, team effects, faceoff wins, and more. dCorsi, the statistic, measures the difference between a player’s Corsi and their ‘expected Corsi’ – the result if that player’s minutes had been played by “a perfectly average player in an average season if he was handed the same minutes with the same players against the same opposition”. Expected Corsi is calculated using a multivariate linear regression of the previously mentioned factors and others, including position, age, and TOI. Simply, a player is driving possession if their Corsi is higher than their Expected Corsi. dCorsi isn’t calculated as a singular piece: it’s split up into dCorsi For (offence) and dCorsi Against (defence). Generating shot attempts and preventing them are not highly correlated, so being able to identify contributions both defensively and offensively is really useful and interesting. Burtch explains the intuition and the mechanics of dCorsi in full here, and the data visualizations for each player in the league are available here.

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