What Corsi really translates to (in numbers that are easy to grasp)

[Elvs]

The average corsi of a player is 50%, so when a player is below that mark he often gets critized.

I will use Cam Fowler as an example, as I'm well familiar with the game he plays and the situation he is in, and because he often gets criticized due to his below average corsi.

This season, Fowler's CF% is 49.09. That's nearly the worst in Anaheim. Now, let's break down what his corsi actually means.

• Game by game (this season), Anaheim gets outshot by 0.38 shots per game when Fowler is on the ice.
  
  
• It takes nearly 8 full periods of hockey for Fowler to become a -1 in shot attempts for/against.
  
  
• 4,3% of all shot attempts during even strenght (5 on 5) against Anaheim results in a goal. At that rate, Fowler must play 186 periods of hockey before those extra shots against him adds up to a goal. That's 62 games.
  
  
• If he was on a team that was getting average goaltending, it would take 201 periods or 67 games before Fowler becomes a -1 in goals for/against.
  

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Of course, that goal could be of great importance. Or it could be completely insignificant. He could be a plus player if the goalies were playing better, or if the attempts for are better than the attempts against. Or he could end up with worse than -1 if the opposite is true.

These are things we'll never know, because corsi doesn't give a damn about goaltending, shot quality, or when goals are scored. But hopefully this puts things into perspective. So that the next time you decide to criticize a player based on corsi, you'll realize how small marginals we are actually talking about in the greater scheme of things.

A center who is 49% in the faceoff dot isn't all that good at faceoffs, but out of a hundred faceoffs, he's only losing two more than he is winning. The differance is that FO% can easily be applied to one individual. But with corsi, things get very complex when you try to apply it to just one single player.

Click to read more...

 

[gorangers0525]

Raw corsi is irrelevant, 49% could be awesome on a bad corsi team or terrible on a good corsi team. It is less than averagein Anaheim but not as bad as usual.

Now try comparing Fowler's 49.1%CF to Manson's 53.9...

 

[wintersej]

Who is Fowler playing with, who is he playing against, zone starts, etc...

Individual Corsi gets way more dicey than team Corsi. I think it's helpful for extremes (Bergeron or Jon Scott), but I would hope the eye test would have caught that Bergeron is good and Scott is bad.

 

[Filthy Dangles]

so Fowler isn't necessarily getting scored on out there but he's also not doing enough for Anaheim to consistenly outscore the other team, either....?

 

[gorangers0525]

Who is Fowler playing with, who is he playing against, zone starts, etc...

Individual Corsi gets way more dicey than team Corsi. I think it's helpful for extremes (Bergeron or Jon Scott), but I would hope the eye test would have caught that Bergeron is good and Scott is bad.

Zone starts have almost zero impact on corsi, QOC a little but it tends to even out over any significant sample size.


Who you're playing with can make or break you though when it comes to corsi, especially defensive partners.

 

[Elvs]

so Fowler isn't necessarily getting scored on out there but he's also not doing enough for Anaheim to consistenly outscore the other team, either....?

Yes but then again the assumption is that all shot attempt are equal. If Fowler and Stoner ends the season at the same CF%, is Stoner contributing just as much as Fowler offensively?

Also, special teams matters. For some reason some seem to think it doesn't, when it's often vital to winning or losing games. Fowler is doing his fair share on the power play this season, and it has helped his team win games.

Yes it's true that Fowler has played his best 5 on 5 hockey this season when he's been paired with Manson. I don't see why that's suprising, as PMD's often thrive next to the type of defenseman that Manson is. Just like Manson benefits from playing with players who can move the puck for him.

Either way, my main purpose of the thread was just to point out how small the marginals are. A CF% of 55 and a CF% of 45 isn't nearly as big as it may sound. Not over the course of just one season.

 

[aufheben]

Yes but then again the assumption is that all shot attempt are equal. If Fowler and Stoner ends the season at the same CF%, is Stoner contributing just as much as Fowler offensively?

Also, special teams matters. For some reason some seem to think it doesn't, when it's often vital to winning or losing games. Fowler is doing his fair share on the power play this season, and it has helped his team win games.

Yes it's true that Fowler has played his best 5 on 5 hockey this season when he's been paired with Manson. I don't see why that's suprising, as PMD's often thrive next to the type of defenseman that Manson is. Just like Manson benefits from playing with players who can move the puck for him.

Either way, my main purpose of the thread was just to point out how small the marginals are. A CF% of 55 and a CF% of 45 isn't nearly as big as it may sound. Not over the course of just one season.

It is actually. It's more than just allowing shots, it's also time that your team doesn't have the puck.

Stralman was 55% last year (1128CF / 919CA) +209
Holden was 45% last year (1267CF / 1561CA) -294

That's a difference of 503 shot attempts. Unless I did the math wrong which is totally possible because I'm just having coffee now lol

On a team level, the Avalanche ended up with a 44CF% last year, which translated to a -828 shot attempt differential.

Fowler's % relative to the Ducks is negative for his career hence people saying he is overrated. A top-pairing defeseman isn't supposed to be the worst on your team in any category.

 

[Elvs]

It is actually. It's more than just allowing shots, it's also time that your team doesn't have the puck.

Stralman was 55% last year (1128CF / 919CA) +209
Holden was 45% last year (1267CF / 1561CA) -294

That's a difference of 503 shot attempts. Unless I did the math wrong which is totally possible because I'm just having coffee now lol

On a team level, the Avalanche ended up with a 44CF% last year, which translated to a -828 shot attempt differential.

You are comparing one of the best players (Stralman) on of the best teams in the league to a player (Holden) who, due to lack of better options, had to play minutes he shouldn't have to handle on the worst corsi team in the league.

Also, my line of thinking is that hockey is played one game at the time. Not 82. Hence my calculations in the OP. -294 over 82 games sounds a lot worse than -3.58 in any single game, especially when you factor in that none of Holden's teammates had a corsi over 47%.

Even at -3.58 per game, it would take seven games before those shot attempts results in a goal against. And without watching the games, it's impossible to say how many of those he'd be truly at fault for.

If we are blindly just looking at corsi, then Erik Johnson hurt Colorado more than Holden did a season ago. I don't believe that to be true.

Fowler's % relative to the Ducks is negative for his career hence people saying he is overrated. A top-pairing defeseman isn't supposed to be the worst on your team in any category.

Fowler used to be overrated by Ducks fans, but has now become underrated by fans of other teams. His career corsi looks a lot less awful if you ignore his rookie season, where his CF% was 41%. And yes, it should be ignored because he was an 18 year old playing on one of the worst teams in the league that season. And because it was an anamoly. He was a -397 in shot attempts for/against that season. His 2nd worst season is -66.

 

[aufheben]

It's 55% versus 44%, it doesn't matter which player it is. Some fanbases put more stock into Corsi than others, if you don't think it's important you don't have to.

 

[Elvs]

It's 55% versus 44%, it doesn't matter which player it is.

Barrett Jackman, Jakub Kindl and Robert Bortuzzo were 55% last season.

Rasmus Ristolainen, Jonas Brodin, Adam larsson, Tyson Barrie and Erik Johnson were 44-45%.

I'd say it matters.

 

[aufheben]

Barrett Jackman, Jakub Kindl and Robert Bortuzzo were 55% last season.

Rasmus Ristolainen, Jonas Brodin, Adam larsson, Tyson Barrie and Erik Johnson were 44-45%.

I'd say it matters.

You said "the difference between 45% and 55% isn't that big". It is. I wasn't comparing Stralman to Holden, I was showing the difference between those percentages.

 

[aufheben]

2015-16

Kings 56.4% 4082/3159 +923
Avalanche 44.2% 3193/4035 -842

 

[Elvs]

You say "the difference between 45% and 55% isn't that big". It is.

I said the differance isn't as big as it sounds. I'm taking the numbers and I'm trying to break down what they actually mean on a game-per-game basis, instead of 82 games all at once.

If we are strictly just talking about scoring, it's gonna take seven full games before Holden's corsi has done more harm than good for his team. That's how long it would take for his corsi to result in more goals against than for.

I'm not denying that Holden is a mediocre defenseman who ideally should play a #6 role maximum. But it's my belief that almost any player in the league can be above 50% or below 50% depending on the situation they are in. Few players are as bad as they are labeled to be. Most can be decent in the right role and situation.

 

[Elvs]

2015-16

Kings 56.4% 4082/3159 +923
Avalanche 44.2% 3193/4035 -842

What about it? I've never suggested that corsi is a bad team stat. I've said it becomes very complex when you start applying it to individual players.

Is your belief that Holden would stay at a CF% of 44% if he had been traded to the Kings last season? I doubt you believe that so I'm not sure what you're getting at here.

 

[aufheben]

I said the differance isn't as big as it sounds. I'm taking the numbers and I'm trying to break down what they actually mean on a game-per-game basis, instead of 82 games all at once.

If we are strictly just talking about scoring, it's gonna take seven full games before Holden's corsi has done more harm than good for his team. That's how long it would take for his corsi to result in more goals against than for.

I'm not denying that Holden is a mediocre defenseman who ideally should play a #6 role maximum. But it's my belief that almost any player in the league can be above 50% or below 50% depending on the situation they are in. Few players are as bad as they are labeled to be. Most can be decent in the right role and situation.

I know what you said, it's incorrect.

 

[2advanced4u]

this whole thing is wrong

CF% is in percentage not shot differential

 

[Elvs]

I know what you said, it's incorrect.

One way of phrasing it: Cam Fowler's corsi is 49.09%.

Another way of phrasing the same stat: It's gonna take 62 games (with the Ducks goaltending) for his corsi to result in more harm than good.


The first way of phrasing it doesn't make his corsi sound worse?

 

[aufheben]

I'm just responding to the 45% v 55% statement, I can't get involved in another Cam Fowler discussion.

 

[g00n]

One way of phrasing it: Cam Fowler's corsi is 49.09%.

Another way of phrasing the same stat: It's gonna take 62 games (with the Ducks goaltending) for his corsi to result in more harm than good.


The first way of phrasing it doesn't make his corsi sound worse?

I'm just responding to the 45% v 55% statement, I can't get involved in another Cam Fowler discussion.

You're both right. I've been saying what Elvs is saying for years. But auf is also correct about the significance of a 10% shift, all other things being equal (usage, teams, opponents, sample size, etc).

Bottom line is these stats CAN mean something in large sets and when looked at for significant and meaningful long-term patterns. But they don't tell us a 50% guy is definitely a better hockey player than a 49.5% guy over the course of a few games or even a season.

 

[MVP of West Hollywd]

It's not just about shots. Shots are used as a way to determine possession. Fowler's Coris would be used to say he is a below average possession player... and the negative impact of that is not as easy as just looking at the shots

 

[SladeWilson23]

You are comparing one of the best players (Stralman) on of the best teams in the league to a player (Holden) who, due to lack of better options, had to play minutes he shouldn't have to handle on the worst corsi team in the league.

Agreed. I don't think it's fair to simply attribute a player's corsi to that player.

Also, my line of thinking is that hockey is played one game at the time. Not 82.

THIS. THIS. THIS. THIS.

Hence my calculations in the OP. -294 over 82 games sounds a lot worse than -3.58 in any single game, especially when you factor in that none of Holden's teammates had a corsi over 47%.

Now this is where I have to somewhat disagree. Problem is that standard deviation is also a thing, and it's not like Holden was -3.58 in every single game. But your overall point is still valid.

Even at -3.58 per game, it would take seven games before those shot attempts results in a goal against. And without watching the games, it's impossible to say how many of those he'd be truly at fault for.

Again, standard deviation. Also goals don't fallow the law of averages. Goals are a lot more sporadic, and there really is no correlation between goals and shots.

If we are blindly just looking at corsi, then Erik Johnson hurt Colorado more than Holden did a season ago. I don't believe that to be true.

I don't think enough people look into the whys and hows of corsi.

Fowler used to be overrated by Ducks fans, but has now become underrated by fans of other teams. His career corsi looks a lot less awful if you ignore his rookie season, where his CF% was 41%. And yes, it should be ignored because he was an 18 year old playing on one of the worst teams in the league that season. And because it was an anamoly. He was a -397 in shot attempts for/against that season. His 2nd worst season is -66.

His Corsi definitely does make him look worse than he is. Andy Greene and Adam Larsson also had below 50% CF% for the Devils last year, and both are phenomenal defensemen.

 

[NoQuitInNewMexico]

Wouldn't a guy like Fowler get a lot of offensive zone starts? If you get a lot of offensive zone starts and you're still a negative player that's a big problem. It's why I never really fell in love with Keith Yandle, we threw him out when the team had already gained the zone so much more often than we did with other players.

But yeah, a lot of people focus on small differences and make them sound huge (similar to faceoffs, what's the math formula for a .53 player beating a .47 player on the draw?), and a lot of niche Corsi players like idk Patrick Wiercioch don't really replicate their success year to year

 

[Sojourn]

Wouldn't a guy like Fowler get a lot of offensive zone starts? If you get a lot of offensive zone starts and you're still a negative player that's a big problem. It's why I never really fell in love with Keith Yandle, we threw him out when the team had already gained the zone so much more often than we did with other players.

But yeah, a lot of people focus on small differences and make them sound huge (similar to faceoffs, what's the math formula for a .53 player beating a .47 player on the draw?), and a lot of niche Corsi players like idk Patrick Wiercioch don't really replicate their success year to year

No, because Fowler isn't strictly an offensive defenseman. That's an old label that hasn't been true of him for years. The guy you're probably thinking of for that role was Vatanen. At least, in the past. Last season he started to become more solid defensively, and he's just in a true top-4 style role now, without the benefit of those favorable starts.

Under Boudreau, Fowler was the go-to guy for breaking the puck out of the D zone. When Fowler had the puck on his stick, you could pretty much count on him to get it out. Cleanly, and in full control. He's silly good at it. He has a similar role under Carlyle too, but instead of going for a change after the puck gets out and is in the offensive zone, he's getting involved more offensively.

 

[Doctor No]

there really is no correlation between goals and shots.

How so?

 

[Machinehead]

If you really think there's no difference between 55% and 45%, I just don't know what to say about that.