Updated Adjusted Corsi

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Via Flickr

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Adjusted Corsi isn’t perfect, but it allows us to get a much clearer picture of what a player’s visualized Corsi actually means. There are some effects we won’t be able to completely correct for; teammates who are really good or are really bad can have a huge impact we can’t cut out all the way. In case you’re not familiar with adjusted Corsi, know that it adjusts a player’s Corsi On for starting position, quality of teammates and quality of competition.

Let’s take a look at the updated numbers. Less than 30 games means you’re not counted. Chart is sorted by GP.


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Forward Raw Corsi% Expected Corsi Adjusted Corsi
Mikael Backlund 51.4 -8.1 9.3
Joe Colborne 47.1 -8.7 2.6
Lance Bouma 43.6 -12.7 -5.5
Brian McGrattan 37.7 -7.9 -21.5
Sean Monahan 45.4 -6.0 -4.3
Jiri Hudler 47.6 -5.6 2.0
Matt Stajan 48.1 -11.7 5.1
Mike Cammalleri 51.3 -7.2 9.1
TJ Galliardi 50.6 -9.0 8.9
David Jones 45.3 -12.1 1.9
Paul Byron 49.8 -8.2 3.9

Mikael Backlund leads the pack here, as usual. The Forward is having better than a superb season thus far, taking on the toughest comp the league has to offer and regularly outshooting them. Joe Colborne has also shown well (or, at least, better) compared to earlier in the season. The move to wing has had a noticible effect on his shot attempt numbers; it’s good that he’s found a home on the right side. If your expectation is for Colborne to be a 3W, you’ll be happy to know he’s almost already there – #239 in PPG among regular forwards. Top 270 are considered at least 3rd liners.

I was a little surprised to see Lance Bouma with such a poor total; even if we had used Fenwick numbers I think Bouma would be under the watermark still, but a lot of it probably has to do with him playing with McGrattan and Westgarth so much. I think we’d see that number tick up a little if he got away from those two players – some suck you just can’t adjust enough for. This is further evidenced by the 7.5% Corsi jump Bouma gets when he’s away from McGrattan and almost 3% when he’s away from Butler. If he can’t demonstrate the ability to get over the hump next year, though, I’m going to be a lot less lenient. 

Monahan gets a bit of a pass as well, since he’s 19 – but he’s played with much better teammates and has a high OZ% but hasn’t really been doing much with it in terms of shot attempt differential. Obviously this doesn’t matter as much right now as it does for the guys who are fully-developed players but I’d still like to see it on the right side of the ledger.

Cammalleri has had these types of results for as long as I can remember. He’ll probably still be a good possession player into his mid-thirties but I don’t want to pay a 33 year old possession player a scorer’s rate, which is what he will probably be seeking. Still, for right now, these are really good results. 

Stajan, like Cammalleri, will probably be a good possession player into his mid-30s but he’s being paid like a 3rd liner, not a 30-goal guy. Good results, good contract, good player – might as well keep him around. I doubt he was worth more via trade than what he’s worth to the Flames on-ice.

We talked at length about TJ Galliardi a short time ago and his results are still stellar. No idea what happened to him this season, but he’s turned into a juggernaut of some sort.

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Jones, Byron and Hudler are mostly coasting out there. Not much difference between them and the other team but all three still have positive numbers.

McGrattan is here to hurt people. He’s not that good at hockey. Kevin Westgarth hasn’t played 30 games for the Flames yet, but his number is worse than McGrattan’s via the eyeballin’ it method. 


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Forward Raw Corsi% Expected Corsi Adjusted Corsi
TJ Brodie 52.1 -10.1 9.8
Chris Butler 44.0 -10.2 3.7
Kris Russell 45.0 -7.1 0.8
Mark Giordano 54.2 -10.7 12.1
Ladislav Smid 41.3 -7.3 -6.8
Dennis Wideman 45.9 -5.8 0.8
Shane O’Brien 44.0 -5.2 -5.6

TJ Brodie and Mark Giordano look fantastic here, but like Backlund, where don’t they put up good numbers?

I was a little surprised to see Butler with that high of a number, honestly, but then I realized that a lot of his numbers and perception of his play are based on thee fact that he starts about 42% of his shifts in the defensive zone. He’ll also get a little bump based on his play with Brodie earlier in the year but not more than a quarter of an event. If I recall correctly, Butler has done pretty well in adjusted Corsi over the years but that’s something we’ll further look into at the completion of the season.

Kris Russell has been the beneficiary of the highest on-ice SH% among these 7 (~9.1%, which is ~1% above league average), so that’s probably why he’s looked as good as he has. His adjusted numbers are still above the water mark, although I would prefer him as a number 5. Basically, I’d be okay with a Russell-Butler 5/6 pairing that gets about even ZS. 

I got a little pushback on Tuesday when I said Smid was, well, brutal. This seems to confirm it. Everyone gets worse when they’re on the ice with Smid and he’s been the team’s second worst defenseman. I understand that some people don’t believe that “defensive defenseman” are rated fairly by CF% or whatever but this is the way it is: a player either gets shot attempts for or stops shot attempts against. If a defensive defenseman has a negative CF% that means he’s not suppressing shot attempts enough to be beneficial to the team in the long run. I assume that people consider defensive defensemen to be better at suppressing Corsi events than generating them but Smid doesn’t even really do that: his 880 Corsi events against in 55 games with the Flames puts him with these players:

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Most of the guys on this list have 10+ more games than Smid does and all of them except for Kulemin (who plays on the tire fire that is the Leafs) have more minutes played than he does. The other guys are players that we would probably consider on the lower end of the scale. I believe all of the numbers here are purely his Flames results, too. I can’t find any way that Smid is providing value presently, at least in ways that are showing up in results. If you can, please share. Otherwise, I think Smid should be one of the two compliance buyouts this summer.

Wideman takes a big hit in adjusted Corsi because of how often he starts in the offensive zone – still over 60% of the time. In saying that, he should obviously be doing more with his high start ratio. I think Wideman would be a prime buyout candidate if they didn’t have cap floor issues next year; his contract was horrible the day it was signed and now that his run of good play is behind us I don’t think you should be paying $5.5 million for a PP specialist.

There’s a reason Shane O’Brien is in the minors and likely won’t get another NHL shot.


Hopefully this has provided a little more context for the numbers we saw on Tuesday. Some time in May we’ll take a look at the whole-season numbers for the whole team in both adjusted and visualized Corsi.

  • If I recall correctly, Butler has done pretty well in adjusted Corsi over the years but that’s something we’ll further look into at the completion of the season.

    Nope. Worst of the bunch last year.

    Butler seems okay when he’s not expected to be the puck handler in a pairing. If the other guy is slower or less coordinated than him, the pairing goes down in Flames.

    • ChinookArchYYC

      That’s actually a pretty good assessment. In his first year with Bouwmeester he was okay, as long as Jay moved the puck up the ice. He seems to be much more comfortable sitting back and letting his partner pinch.

      He also tends to pass the puck off instead of carrying it out of his own end. When he tries to skate up the ice, he gets into trouble.

  • ChinookArchYYC

    It really sucks that Galiadri likely won’t be re-signed after having a very strong year for the Flames. What’s really scary to think is the idea of Burke being dumb enough to give us another season of Westgrath and McGrattan on the 4th line

  • beloch

    Wotherspoon has been Smid’s primary partner since Wideman was injured. He’s been looking better and better each game, all while playing with Smid. That’s why I’ve been a bit bullish about the kid even if we don’t have an adequate sample size yet. Smid’s QoC hasn’t really gone down since Wideman was injured, but he seems to be doing slightly better with Wotherspoon than he was with Wideman. That’s another arrow pointed in the right direction for Wotherspoon.

    Smid, I really wonder about. His possession stats have actually gotten worse since moving to Calgary despite having better team-mates and facing easier competition. He had better raw corsi for several seasons as a top-pairing defender in Edmonton than he does on the third-paring in Calgary this season. The way he lumbers around on the ice just looks painful. He does not look like a guy who’s just 28. He’s too young to have declined so much due to age. It’s very possible something is seriously wrong with him.

    Smid is a player who could rebound next season. Unfortunately, he’ll still be overpriced for a third-pairing defender even if he does rebound. Compliance buyouts must be used by July 1st, so keeping him around is definitely a risk. Still, the Flames could likely afford to keep him if they so choose. Again, he really doesn’t look like a 28 year old should out there. Hopefully whatever’s wrong with him is something that can heal.

    Whether Smid stays or goes, I still think the Flames need to find another high-end 2nd line defender with the potential to play top-pairing minutes if Giordano or Brodie are injured. Butler has improved a lot since last season and Russel has really stepped up, but they’re still a weak second pair by league standards. It wouldn’t be a bad move to trade one of those guys and another asset for an upgrade. If Wideman rebounds next season that would result in a very solid second pair with either Russel or Butler left over for the third pairing, where either one would probably be very solid.

    • ChinookArchYYC

      Comparatively speaking defense has been a relative strength for Calgary. The trouble with moving Smid out is that he’s one of the bigger defenders on the team, and I don’t see the Flames getting smaller on D. Witherspoon is a big kid, so if he’s actually ready to make the jump as a bottom pairing guy that might help in upgrading on Smid.

      If Burke is creative, I believe there may be a market for Smid. Smid can find a home else where, if he was cheaper. So, it may be advantageous to take money back on this contract over the next couple of years. If Burke did this, the team might recoup a late round draft choice. David Jones is on the top of my buyout list!

    • Smid was at least competent in EDM for years. This season, he’s probably not even replacement level. Oilers fans swear to me he used to be able to skate, so I’m thinking something’s gone wrong with him physically as well.

      If he can recover over the summer, he might rebound. If it’s chronic and degenerative, though, he needs to go.

  • beloch

    So some weirdness happened in the QMJHL yesterday. Gatineau beat Cape Breton 7-1 to get the sweep in the series. Somehow, two of the three stars were Cape Breton defensemen (who were a combined -3 with no points). The third star was Gatineau’s goalie, who made all of 17 saves.

    Meanwhile, Poirier had three points, Reway had two goals, and another teammate of theirs had three assists. I have to say that something really weird is going on if your team’s goalie is your only star in a 7-1 game where you out shot the opposition 31 to 18.

  • The Last Big Bear

    1) A juggernaut of the 3-goal variety.

    2) Mikael Backlund. F*#% YEAH.

    3) Adjusting the Corsi for forwards added basically no new information. You get essentially the same list in the same order using either method.The pearson and spearman correlation between adjusted and non-adjusted Corsi lists for the forwards were both 97%.

    4) For defencemen on the Flames, raw corsi correlates to ice time better than adjusted Corsi. Since TOI is the best available stat for defencemen, this likely tells you you’re losing some information in the adjustment. Let me explain why:

    I will use a comparison to blocked shots. It has become accepted on the nations network that blocked shots are a bad thing, because it means the player doesn’t have possession and is giving up shooting attempts. And like your explanation of CF%, it makes perfect sense as a narrative. And like CF% on the Flames, this is almost exactly what we see. On this team there is an almost directly inverse relation between shot-blocking and overall ability: Butler at the top, followed by Smid, Russel, then Brodie and Giordano, in that order. Done deal?

    But a quick look at the NHL’s top-20 shot blockers shows they include Shea Weber, Alex Pietrangelo, Niklas Kronwall, Marc-Edouard Vlasic, etc. This is similar to what we see with CorsiRel. A mix of terrible and excellent players at the top of the list, a warning sign that we may be on the wrong track.

    Sure you could make an “Adjusted Blocked Shots”, based on things like TOI, quality of competition, linemates. But those are all based on the coach’s judgement, and here is where we get to my point:

    What is the coach’s judgement based on? Underlying player ability.

    By adjusting out coach’s discretion and factors associated with a coach’s decisions, you’re largely adjusting out player ability, which is what those decisions are based on and which is exactly what we’re trying to measure. I think that’s one of the main reasons why its so hard to get a stat that meshes with defenceman’s ability.

    5) This doesn’t seem to be as much of a problem with forwards. As we noted above, your adjusted Corsi had the same descriminating ability as Raw Corsi. I expect this is because Corsi is a better measure to start with for forwards, but this may also not generalize across the league.

    6) Keep up the good work.

    Edit: Oh yeah, and 7) Brian McGrattan transcends statistical analysis. He’s like on a whole different level.

    • beloch

      It has become accepted on the nations network that blocked shots are a bad thing, because it means the player doesn’t have possession and is giving up shooting attempts.

      That’s a bit of an oversimplification. Obviously blocking a shot is better than not blocking a shot. Shot blocking is a useful skill. The issue is when it results in perpetual possession for the other team–your player can’t block every single shot. The more attempts he gives up, the more opportunities the other team has to get one through and get scoring chances.

      We saw this sort of thing a lot with Anton Babchuk. He “blocked” a lot of shots, and people used that as proof that he could play defense. But there’s more to playing defense than acting as a speed bump. Ultimately, you have to regain possession of the puck (or at least get it out of the zone). Chaps like Weber and Pietrangelo are very good at that. Butler isn’t (and Babchuk was much, much worse).

      • The Last Big Bear

        I agree. Lots of shot blocks can be a good or bad thing, and the number in itself tells you nothing. Like +/-, it is usually either ignored, or used to support a pre-conceived idea of a player, and as such I don’t think it’s a useful measure at all.

        My point was that I don’t think blocked shots is a good stat for evaluating defenders, and “adjusting” it only makes it worse. In the same way that I don’t think Corsi measures are a good stat for defencemen, and adjusting them likewise doesn’t improve them.