Flames Close Game Corsi

Robert Vollman
December 23 2011 11:38AM

 

 

Every week in the Black Box statistical summaries we rank the Flames by Corsi event percentage, which is just a fancy way of describing the percentage of all attempted shots (saves, goals, goal posts, missed nets, blocked shots, whatever) taken by the Flames rather than their opponents when the given player is on the ice.  We love it because it's also the best proxy we have for things like possession and territorial advantage, at least until someone gets out stopwatches every game.

While many of Corsi's caveats have already been covered, like how often a player starts in the opposing zone instead of their own, or the average quality of their competition, there has always been one unspoken caveat: score effects.  Both statistically and subjectively we can see that teams with either big leads or late leads tend to sit back, dump it in, and let their opponents come to them.  Consequently a player who is awarded a disproportionate amount of ice-time in such situations is going to have better shot-based metrics, like Corsi.

To allow for that we used Vic Ferrari's famous time on ice application to peel out only the Corsi data for time when the game was close (within one goal early in the game, or tied late in the game).  His site also offers up plain old shot percentage, and Fenwick percentage (Corsi but without blocked shots), but they turn out roughly the same.

As for the Calgary Flames, here's how the forwards look, as of the start of their extended (and likely to be highly forgettable) holiday road trip.


Forwards        Corsi%
David Moss       60.5%
Tim Jackman      60.1%
Blake Comeau     58.3%
Lee Stempniak    56.3%
Tom Kostopoulos  55.1%
Brendan Morrison 53.0%
Matt Stajan      52.9%
Mikael Backlund  51.2%
Paul Byron       48.6%
Rene Bourque     48.3%
Roman Horak      46.2%
Olli Jokinen     46.1%
Alex Tanguay     45.9%
Jarome Iginla    43.4%
Curtis Glencross 42.7%
Minimum 3 games

This is largely what weekly followers of the Black Box were expecting, except that the situational effects seem to be exaggerated. Those who start more often in the offensive zone or against lighter competition seem to do even better in close game situations, especially Tim Jackman and Blake Comeau, while those who routinely face top opponents like Jarome Iginla and Curtis Glencross fare far worse.

It stands to reason that situational effects would apply more early on or when the game is close, because it's in those situations that coaches would probably cling most tightly to their desired player roles and match ups, saving any shake-ups or experimentation for when the game has gotten out of hand.

Let's see if that patterns holds up on defense.


Defensemen        Corsi%
Cory Sarich        53.8%
Derek Smith        53.8%
T.J. Brodie        52.8%
Joe Piskula        51.9%
Chris Butler       50.4%
Jay Bouwmeester    49.0%
Scott Hannan       46.8%
Mark Giordano      44.6%
Anton Babchuk      42.9%

Among defensemen there doesn't seem to be any change at all, suggesting that score effects may have more of an impact on forwards than the blue line. Possibly coaches stick to their prescribed roles and situations for their blue lines regardless of score, which certainly jives with what we've seen subjectively with the Flames.

As for goaltending, one thing is for certain, the Flames have certainly played better in front of Mikka Kiprusoff than the others, which is especially surprising since they would normally rest Kiprusoff when they're up against a lighter opponent.


Goalie           Corsi%
Miikka Kiprusoff  51.5%
Henrik Karlsson   46.3%
Leland Irving     38.6%

Though this is only a small sample size, don't be too hard to Henrik Karlsson, because it appears that a completely different team has been playing in front of him than Miikka Kiprusoff.

Conclusions from this quick study?  Score effects seem to be more pronounced for forwards than for defensemen, and appear to have the ultimate effect of simply exaggerating their situational effects, like offensive zone starts and quality of competition.  We'll keep an eye on this as the season progresses.

781445e1560a4e1d0d641bc270a7eedc
Rob Vollman of www.HockeyAbstract.com is a regular feature writer on ESPN Insider, co-author of Hockey Prospectus 2010-11 and 2011-12, and regular contributor to NHL Numbers, Flames Nation and Arctic Ice Hockey. Innovator of Player Usage Charts, Quality Starts, GVS (Goals Versus Salary), the Snepsts Projection System, and known for work in League Equivalencies (NHLE). Twitter: @robvollmanNHL
Avatar
#1 Kent Wilson
December 23 2011, 11:40AM
Trash it!
0
trashes
Props
0
props

Flames inverted pyramid in full effect.

Avatar
#2 Tach
December 23 2011, 12:45PM
Trash it!
0
trashes
Props
0
props

Rob,

Did you manually assemble this data off timeonice.com or from Gabe's new tools? Just curious because I am always interested in this data.

Also, I am curious about this statement:

"situational effects would apply more early on or when the game is close"

Maybe I am just misinterpreting, but I always think that situational effects actually get more pronounced when a team has a bigger lead early or a small lead later in the game. For example, when a team gets up by a few goals early or when protecting a one goal lead late, they will tend to give up more possession than when tied or close early in a game. This is based on the theory (which the Flames frequently prove to be largely dubious)that you can reduce scoring chances or shooting percentage by not pursuing posession.

Are we on the same page on this or am I missing something?

Avatar
#3 Rain Dogs
December 23 2011, 01:39PM
Trash it!
0
trashes
Props
0
props

"Though this is only a small sample size, don't be too hard to Henrik Karlsson, because it appears that a completely different team has been playing in front of him than Miikka Kiprusoff."

Can someone chime in on where we are with goalies? Or do we not know?, cause that's ok too

I thought the latest was that the higher the corsi for in front of the goalies generally correlates with lower sv%, based on Tom Awads numbers.

Or, for fear of stirring up a massive flame-war, the counter-attack team (lower corsi team) creates higher "opportunity" chances for during counter attack.

So, meaning that Miikka likely faces the highest quality against and Irving the lowest (understanding small sample blows it all out of the water, but let's imagine those corsi #'s were over 2000evSA.)

Certainly, there will be outliers, but this intuitively makes sense to me through mid-level teams, and based on my experience in goal and instructing makes sense. I'm skeptical with dominant teams like Boston.... but I dunno, maybe they're the outlier.

Are we not there? Do we know? Should I just stop trying to understand what these numbers mean re: goaltending?

Comments are closed for this article.