A little perspective on the current star defenseman

[wgknestrick]

If one completely filters out SV% while on ice (during SA), then doesn't that penalize d-men which prevent high quality shots? So a d-man who takes chances that either results in no shots or often in a high quality shot will appear better than one which prevents most high quality shots, but allows more low quality shots.

I understand the luck component in the shorter term, so maybe it would be better to see results both ways. In a longer term study, one could get an average of SV% on/off for each d-man and adjust based on that, right?

IE Alex Goligoski

Pure offensive defenseman that has had generally good corsi and +- results his entire career. Also has been near the bottom of his team (DAL and PIT) in SV% ON for almost every year he's played. Why? He is a very small defenseman that while very talented with the puck, has trouble limiting shots in the high percentage areas due to his lack of size. He cannot clear the crease of screening forwards or prevent shots in the crease.

He generally plays somewhat sheltered minutes and gets favorable zone starts to minimize his exposure to his weakness. If you don't look at SV% ON you'd never find this flaw in his game. Zone starts and qual comp would indicate something is different with him but not give you the smoking gun that SV% ON does.

 

[barneyg]

Zone start vs QoC depends on whether you are using shot-based or goal-based metrics. QoC is relatively more important for goal-based metrics like plus-minus (because top players have better SH%) and zone start info is relatively more important for shot-based metrics like Corsi (because shots off an o-zone faceoff tend to be low %).

That makes sense as a general explanation but if among top d-men there's a wider range in %OFF zone starts (e.g. Karlsson 57% vs Weber 45%) than the range in QOC (OP's assumption which I think is flawed, as I explained previously), the %OFF adjustment may still be more significant on +/-.

 

[barneyg]

IE Alex Goligoski

Pure offensive defenseman that has had generally good corsi and +- results his entire career. Also has been near the bottom of his team (DAL and PIT) in SV% ON for almost every year he's played. Why? He is a very small defenseman that while very talented with the puck, has trouble limiting shots in the high percentage areas due to his lack of size. He cannot clear the crease of screening forwards or prevent shots in the crease.

He generally plays somewhat sheltered minutes and gets favorable zone starts to minimize his exposure to his weakness. If you don't look at SV% ON you'd never find this flaw in his game. Zone starts and qual comp would indicate something is different with him but not give you the smoking gun that SV% ON does.

That's a compelling explanation but do you have other evidence of this? Goligoski was 3rd on the Pens 2009-10 for SV% ON so that story only works in Dallas so far.

 

[WhiteLight*]

I've wondered this myself, and I personally reject the premise that QoC doesn't matter at all - despite the studies people have done on it.

I do however accept the fact that the difference over 82 games in QoC between any first pairing defenseman is so negligible that it doesn't warrant adjustment.

I don't think there needs adjustment on QoC - if all defensemen are top 2 on their teams.

Karlsson, Weber, Chara, etc are all top 2 and play against top lines.

However, in the OP, Letang leads many categories, and he is 4th on his team in QoC. He doesn't/didn't face top quality opposition, just 2nd/3rd/4th lines. Therefore Letang's stats are inflated.

Yeah sure, sorry, what I did above is using +/- per 60 relative to team, as well as +/- per 60 relative to 10-most common teammates, as such it is a relative stat.

As such, if we are going to consider zone starts %, it needs to be relative to the team he plays on. That way, if we are going to say for instance:

Player A Team A: +0.20 per 60 relative to team, +0.25 per 60 relative to teammates, 50% o-zone starts

versus

Player B Team B: +0.20 per 60 relative to team, +0.25 per 60 relative to teammates, 50% o-zone starts

We need to know the relative o-zone starts in order to see who was the better player between the two. Perhaps Team A is in the offensive zone 80% of the time and Team B is in the offensive zone only 20% of the time. The fact that Player B has 50% o-zone starts despite the fact that his team is almost never on the attack shows he is being used in an offensive role and only getting +0.25 per 60 relative to teammates. It should be easier for him to get +/- relative to team/teammates since he's being used in a more offensive role. While Player A is playing 50% o-zone starts despite the fact that his team is almost always on the attack and as such is being used in a defensive role, and yet he still manages to be +0.25 per 60.

Player A is better in this case (all else being equal of course) and that's why you need relative o-zone starts to use in conjunction with relative (to team/teammates) +/- and not nominal o-zone starts.

Not sure about this...

Take Karlsson with his 57%. I think that means that he starts 57% of every faceoff that is not in the neutral zone in the offensive zone, and 43% in the defensive zone.

I don't think it has anything to do with the team, it's individual. If a team starts more in the defensive zone in general, then all their players will have low % offensive zone starts.





Anyway, good job. Did you steal any of my ideas, they look familiar

 

[Sureves]

My point is that the "QOC doesn't matter" conclusion can only be valid if you're looking to split players into broad skill tiers, say: great, average, replacement level. Letang, Keith, Karlsson, etc are always going to show up in the "great" category no matter their QOC -- the uncorrected bias isn't going to be enough to move them down one category. But it's likely to be enough to move a guy from #3 to #10 or vice-versa. So if your goal is to compare the top d-men with each other, you can't say "QOC doesn't matter" and ignore it.

That said, IMO the zone start adjustment is likely to be more important than the QOC adjustment.

I just don't think when we are looking at 1st pairing defenseman that the difference in QoC is going to materially affect anything - as suggested by the article. I do not believe it needs to be adjusted.

 

[Sureves]

What does a defender's SV% on ice have to do with these forwards' SH%?

The argument as I understand it was that if a defender faces better competition, that competition has a better shooting percentage and equivalently the SV% on will be lower (thus, if SV% ON is high, despite high QoC, we could conclude that that defenseman is very good defensively).

I'm merely showing that that isn't true. Extremely often we find that the players who score the most goals do not in fact have the highest shooting percentages and equivalently do not generate the lowest SV% ONs. Luck plays a pretty huge role in shooting percentage and equivalently SV% ON. Are the guys I listed really the best scorers in the NHL (Right Column)? Or are these guys (Left Column)?

Steven Stamkos| Curtis Glencross
Evgeni Malkin |Steven Stamkos
Marian Gaborik | Jiri Hudler
James Neal | Kyle Wellwood
Alex Ovechkin | Jordan Eberle
Ilya Kovalchuk | Nathan Horton
Phil Kessel | David Perron
Scott Hartnell | Tyler Ennis
Corey Perry | Martin Erat
Matt Moulson | Sergei Kostitsyn
Radim Vrbata | Milan Lucic
Michael Ryder | Jordan Staal
Erik Cole | Brad Marchand
Milan Michalek | Michael Ryder
Jason Spezza | Tyler Bozak
Jordan Eberle | Maxime Talbot
Patrick Sharp | Milan Michalek
Max Pacioretty | Chris Kelly
Jarome Iginla | Matt Moulson
John Tavares | David Desharnais
Zach Parise | Valtteri Filppula
Logan Couture | Scott Hartnell
Joe Pavelski | Patrik Elias
Bobby Ryan | David Krejci
Jason Pominville | Kyle Okposo
Daniel Sedin | Nik Antropov
Patrick Marleau | Teddy Purcell
Rick Nash | Eric Nystrom
Evander Kane | Jonathan Toews
David Clarkson | Dainius Zubrus

Left Column (top 30 goal scorers) are generally accepted to be better shooters than the Right Column (top 30 shooting percent), right?

What I'm saying is, shooting percentage is very erratic year-to-year in the short term, and so is save percentage. Just because a defenseman has a higher SV% ON and faces tough competition, doesn't really mean he's excellent defensively, he could just be benefiting from good luck, much like the guys in the Right Column.

This is kind of off topic to my OP though, but I'm happy to discuss it.

 

[Sureves]

Not sure about this...

Take Karlsson with his 57%. I think that means that he starts 57% of every faceoff that is not in the neutral zone in the offensive zone, and 43% in the defensive zone.

I don't think it has anything to do with the team, it's individual. If a team starts more in the defensive zone in general, then all their players will have low % offensive zone starts.

We are comparing a player's +/- relative to his team, and we are comparing +/- relative to his top 10 most common teammates, as such, if we are going to consider zone starts, we need to compare it also relative to his team.

Player A Team A: +0.50 relative to team, +0.50 relative to top 10 teammates, 50% zone start
Player B Team B: +0.50 relative to team, +0.50 relative to top 10 teammates, 50% zone start

Which one is better? Contrary to what you'd think, they aren't equal. It depends on what their relative zone starts are. If team A is on the attack 90% of the time, and Player A has half his zone starts in the offensive zone, clearly he is being used very defensively.

Similarly if Player B's team is on the attack only 10% of the time, but he's having half his zone starts in the offensive zone, obviously he is being used in a very offensive role.

It will be easier for Player B to generate +/- relative to team, +/- relative to top 10 teammates than it will be for Player A: much easier, despite the fact that technically their zone start percentages are the same.

Also for the record, Weber's relative zone starts are 49%, Karlsson's are 52.50% adjusted to assume 50% Team Offensive Zone Starts.

 

[WhiteLight*]

We are comparing a player's +/- relative to his team, and we are comparing +/- relative to his top 10 most common teammates, as such, if we are going to consider zone starts, we need to compare it also relative to his team.

Player A Team A: +0.50 relative to team, +0.50 relative to top 10 teammates, 50% zone start
Player B Team B: +0.50 relative to team, +0.50 relative to top 10 teammates, 50% zone start

Which one is better? Contrary to what you'd think, they aren't equal. It depends on what their relative zone starts are. If team A is on the attack 90% of the time, and Player A has half his zone starts in the offensive zone, clearly he is being used very defensively.

Similarly if Player B's team is on the attack only 10% of the time, but he's having half his zone starts in the offensive zone, obviously he is being used in a very offensive role.

It will be easier for Player B to generate +/- relative to team, +/- relative to top 10 teammates than it will be for Player A: much easier, despite the fact that technically their zone start percentages are the same.

Also for the record, Weber's relative zone starts are 49%, Karlsson's are 52.50% adjusted to assume 50% Team Offensive Zone Starts.

OK I get it but I don't think we should compare zone starts. Difference is negligible. No one is like the Sedins.

 

[barneyg]

It will be easier for Player B to generate +/- relative to team, +/- relative to top 10 teammates than it will be for Player A: much easier, despite the fact that technically their zone start percentages are the same.

Also for the record, Weber's relative zone starts are 49%, Karlsson's are 52.50% adjusted to assume 50% Team Offensive Zone Starts.

It's an old (and different) debate but I'm not convinced you want to put all your weight on "relative to team" metrics when evaluating the league's best d-men. Travis Hamonic was #2 in the league for +/- relative to team among d-men, playing tough competition and getting average zone starts. Is he the league's 2nd best d-man? I think he just played on a very crappy team.

 

[WhiteLight*]

It's an old (and different) debate but I'm not convinced you want to put all your weight on "relative to team" metrics when evaluating the league's best d-men. Travis Hamonic was #2 in the league for +/- relative to team among d-men, playing tough competition and getting average zone starts. Is he the league's 2nd best d-man? I think he just played on a very crappy team.

That's the biggest problem with this whole thing.

For example, Dan Girardi had a negative +/- relative to his team. But the guy led the league in ice time and his team finished 1st in the East... he must be doing something right.

 

[seventieslord]

IE Alex Goligoski

Pure offensive defenseman that has had generally good corsi and +- results his entire career. Also has been near the bottom of his team (DAL and PIT) in SV% ON for almost every year he's played. Why? He is a very small defenseman that while very talented with the puck, has trouble limiting shots in the high percentage areas due to his lack of size. He cannot clear the crease of screening forwards or prevent shots in the crease.

He generally plays somewhat sheltered minutes and gets favorable zone starts to minimize his exposure to his weakness. If you don't look at SV% ON you'd never find this flaw in his game. Zone starts and qual comp would indicate something is different with him but not give you the smoking gun that SV% ON does.

If this is true, this just highlights why a shot quality adjusted corsi would be the next logical step.

 

[seventieslord]

That's the biggest problem with this whole thing.

For example, Dan Girardi had a negative +/- relative to his team. But the guy led the league in ice time and his team finished 1st in the East... he must be doing something right.

QoC tells a big part of that, I am sure.

I'm a big fan of icetime though. Coaches are paid millions of dollars to win and they want the players out there most often, that are most advantageous to their team. icetime tells us what they think of their players.

 

[Sureves]

It's an old (and different) debate but I'm not convinced you want to put all your weight on "relative to team" metrics when evaluating the league's best d-men. Travis Hamonic was #2 in the league for +/- relative to team among d-men, playing tough competition and getting average zone starts. Is he the league's 2nd best d-man? I think he just played on a very crappy team.

That's the biggest problem with this whole thing.

For example, Dan Girardi had a negative +/- relative to his team. But the guy led the league in ice time and his team finished 1st in the East... he must be doing something right.

Certainly true. You need to look at all 3: nominal +/-, relative to team +/-, and relative to most common teammates +/-.

I think if Player A beats Player B in all 3 of those metrics while facing similar competition, that really does tell you somethning in most cases.

 

[wgknestrick]

QoC tells a big part of that, I am sure.

I'm a big fan of icetime though. Coaches are paid millions of dollars to win and they want the players out there most often, that are most advantageous to their team. icetime tells us what they think of their players.

Weren't Mike Milbury and Dale Hunter head coaches? Sorry to take a 12gauge to your argument. Coaches are human and will certainly make mistakes in evaluating players. Wise men evaluate as many factors as possible and make decisions on the best data available. TOI does help decide who might be more valuable in a deadlock though.

Not all coaches are wise men.