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"If we have the puck all the time, and our goalie can't stop it, we lose the game."
That's a really hard statement to get behind.
"If the other team never gets a shot on our net, because they never have the puck, and our goalie can't stop it, we lose the game." No you don't. At worst, you tie 0-0.
Hot goaltending has been shown to be unsustainable, whereas corsi dominance has been shown to be repeatable.You're just stating the other ludicrous extreme.
Obviously having the puck more often than the opposition is a good thing in general but I think what he was saying is that if I have the choice between good Corsi rating and a good goaltending performance I'll take the good goaltending every time.
I agree with that.. teams that buck the Corsi prediction trend tend to do so based on their goaltending.
Can you please change the title. Dave Nonis never said "Advanced stats, like Corsi, are useless."
He said "I wouldn't say analytics are useless" and "Corsi and Fenwick are interesting, but that's all they are".
Hot goaltending has been shown to be unsustainable, whereas corsi dominance has been shown to be repeatable.
Even as someone who likes an uses advanced stats, I agree with him. Yes, Corsi is a helpful forensic tool for analyzing outcomes, and has pretty good predictive value. But if you were the GM or coach of a hockey team, what good would Corsi do you? "Your team doesn't do well in the possession game"... well yeah, you know that already. That doesn't help you solve the problem.
"Hot" goaltending is obviously unsustainable, or else it wouldn't be called "hot." Strong goaltending, however, has been and always will be, sustainable by strong goaltenders.
There are a couple of obvious things he can do:
1) Stop signing and trading for players who don't drive puck possession.
2) Stop signing coaches whose tactics don't drive puck possession.
3) Get on the bus and start contributing to the exploration of advanced stats so we can better understand what sorts of team systems and individual skills drive puck possession.
The whole point of analytics is to supplement the eye test. You can't see everything. It's also pretty clear that many of the "common hockey knowledge" beliefs are flat out wrong, when it comes to winning hockey games.What he's saying, though, is that he is already aware of the need to have better puck possession than the other team. He doesn't need extensive number crunching to confirm what common hockey sense would tell him.
Corsi might give him some window into exactly what players to pursue, but then again he also has paid professional scouts whose job it would be to have that kind of information on-hand anyway. Same with coaches -- he could probably tick off the best possession-game coaches in the league without needing to refer to a stat sheet. It's his job to know those figures and to pursue the best ones available.
I would expect an NHL manager to become a pioneer in anything that has been proven to increase the chances of his team winning games.As for #3, I'm not sure why we would expect an NHL manager to become an advanced stats pioneer. They seem pretty busy with other things.
The whole point of analytics is to supplement the eye test. You can't see everything. It's also pretty clear that many of the "common hockey knowledge" beliefs are flat out wrong, when it comes to winning hockey games.
On your point about having a list of coaches who drive puck possession. If not puck possession stats, what would determine where a coach sits on such a list?
I would expect an NHL manager to become a pioneer in anything that has been proven to increase the chances of his team winning games.
It sounds to me like he lacks an understanding of how possession stats relate to other statistics (or other behaviours, like goaltending, that can be measured statistically). His comment that I quoted above, regarding puck possession and bad goaltending, is one example. He doesn't appear to understand basic concepts that relate puck possession to goaltending outcomes (i.e., more puck possession for your team = less puck possession for opponent = less shot attempts against = less shots on goal against = less goals for a given level of goaltending).I don't think he's claiming to see everything. He's saying that he spends all day, every day, reviewing game film and scouting reports. For someone to come along and give him a graph that essentially says "you didn't shoot enough", isn't helpful. He knows that already.
He isn't bashing advanced stats in general, or even targeting Corsi's analytical value. He's saying it isn't useful to him in preparing his team to win games -- primarily because it simply explains what the end-goal of possession should be rather than providing a road map for success which can be applied in a real-world situation.
The only way to understand whether these systems result in increased or decreased puck possession is to actually measure whether or not they do. Someone at some point along the information flow is going to actually have to sit down and determine how each of these systems impacts puck possession by counting something, and the proven (and intuitive) link between shot attempts and puck possession suggests that shot attempts are a good thing to count.Detailed knowledge of the offensive and defensive systems that each coach instills on his team? Some coaches instruct their teams to retain possession at all costs, others emphasize volume-based shooting attempts, others focus on generating a few quick but high-quality rush opportunities.
If there is evidence suggesting that teams that do better at A have historically resulted in more B, and you want more B, then you'd be pretty silly if you didn't at least consider doing better at A.Corsi has been proven to have predictive value regarding a team's chances of winning. I'm not so sure you can say it has been proven to increase the chances of winning through some sort of application.
It sounds to me like he lacks an understanding of how possession stats relate to other statistics (or other behaviours, like goaltending, that can be measured statistically). His comment that I quoted above, regarding puck possession and bad goaltending, is one example. He doesn't appear to understand basic concepts that relate puck possession to goaltending outcomes (i.e., more puck possession for your team = less puck possession for opponent = less shot attempts against = less shots on goal against = less goals for a given level of goaltending).
The only way to understand whether these systems result in increased or decreased puck possession is to actually measure whether or not they do.
If there is evidence suggesting that teams that do better at A have historically resulted in more B, and you want more B, then you'd be pretty silly if you didn't at least consider doing better at A.
If this is the point he's trying to make, it's not a legitimate point. If your goalie sucks, you can only LESSEN the impact of his lack of skill by improving your possession game.I don't think he was saying anything like that, though. He was just throwing out an extreme example about how real-life circumstances can undermine statistical models. IE, even if you dominate possession, you can still lose the game because your goalie sucked. I doubt he meant anything more complex than that.
The problem is without analyzing the outputs, you have no way of evaluating the inputs. Determining that Coach Bob using this sort of X and O's structure is completely useless if you don't bother to determine whether that X and O's structure results in having the puck more often than the other team.Yes but you are talking about outcomes as opposed to inputs. When it comes to hiring a coach, the GM is dealing with the input side of the equation. The results are already known (ie, how good was this guy's team offensively) so it's far more helpful to spend time and resources analyzing that coach's inputs (the Xs and Os of what he instructed his players to do on the ice) rather than continue drilling down into outcome-oriented data just to make redundant conclusions about puck possession.
It seems to me like you're missing a key link in the equation. In order to get information, you have to be willing to actually collect the information. Your argument, in a financial context, would boil down to something like this: "I want to know how much money I have, but I don't really think it's important that anyone bothers to count my money." Or, alternatively "I want to have more money, but I don't think it's important to know how much money I have right now or what impact my decisions have on whether I make more money or not."That's his entire point -- of course he wants to do better at A. He knows that already. Finding new ways to prove the value of A is irrelevant to him. And presuming he already has file cabinets full of information about which coaches and players have skillsets which could contribute more A to his team (which he should if he is doing his job correctly), then further analysis of which players produced the most A last week is simply going to be annoying to him.
It sounds to me like he lacks an understanding of how possession stats relate to other statistics (or other behaviours, like goaltending, that can be measured statistically). His comment that I quoted above, regarding puck possession and bad goaltending, is one example. He doesn't appear to understand basic concepts that relate puck possession to goaltending outcomes (i.e., more puck possession for your team = less puck possession for opponent = less shot attempts against = less shots on goal against = less goals for a given level of goaltending).
Yet there are oodles of people dismissing the importance of statistics that tell us about puck possession.There is no one involved in the game of hockey that doesn't understand this...
Yet there are oodles of people dismissing the importance of statistics that tell us about puck possession.
Let's inject some actual data into the discussion.
Leafs 2013-14 5on5 shot attempts against = 5508
Leafs 2013-14 5on5 shots against = 2945
Leafs shots against per shot attempt against = 0.535
League average 2013-14 5on5 shot attempts against = 4584
League average 2013-14 5on5 shots against = 2464
League average shots against per shot attempt against = 0.538
So there is extremely little difference between the Leafs and the league average when it comes to how many shot attempts toward their own net actually end up hitting the net.
Leafs 2013-14 5on5 SV% = .914
League average 2013-14 5on5 SV% = 0.911
So the Leafs actually had better than average goaltending.
Leafs 2013-14 Goals Against = 252
League average 2013-14 Goals Against = 219
...yet allowed drastically more goals against than the league average.
I wonder how many fewer goals the Leafs would have allowed if they'd had the puck more (and allowed the league average shot attempts against)?
4584 shot attempts against
x 0.535 shots on goal against per attempt against (Leafs actual rate)
= 2452 shots against
x .086 goals against per shot against (1.000 - .914 save percentage - Leafs actual)
= 211 goals against
So average puck possession with the exact same goaltending would have reduced the Leafs goals against by 41. They would have given up exactly 1 less goal every 2 games on average.
So yes, it does matter if your team has the puck more even if your goalie can't stop it.
That is a lot of verbiage to say that, all other things being equal, if you give up less shots you'll get scored on less.. hardly breaking news.
The whole point of analytics is to supplement the eye test. You can't see everything. It's also pretty clear that many of the "common hockey knowledge" beliefs are flat out wrong, when it comes to winning hockey games.
On your point about having a list of coaches who drive puck possession. If not puck possession stats, what would determine where a coach sits on such a list?
I would expect an NHL manager to become a pioneer in anything that has been proven to increase the chances of his team winning games.
1) Hitting more leads to winning more.Such as?