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Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 12:05 am
by Robin Hood
So I've been obsessed with
advanced stats for about a year now. And in BBKL, no one talks about it often enough. Considering how educated this league is otherwise, I think we should have a thread dedicated to discussing it (they're actually one of the reasons I picked up Alfredsson today).
I will be posting any cool articles I find on
stats related topics from here on out. I ask that whoever does read up on stuff like this does the same. Not everything that is posted should be taken as gospel as
advanced stats are far from perfect. But it should get a discussion going.
Below is some information (for those of you new to this), some resources to look up
advanced stats and some interesting articles I've read in the past month or so. I'll post more as we go along.
Introduction on Advanced Stats
http://www.sportingcharts.com/articles/ ... ction.aspx
http://www.grantland.com/blog/the-trian ... in-the-nhl
http://www.habseyesontheprize.com/2013/ ... to-fenwick
http://blogs.thescore.com/nhl/2013/02/2 ... d-the-cbc/
Resources to Look Up Advanced Stats
http://www.behindthenet.ca/nhl_statisti ... &ds=30&f5=
http://stats.hockeyanalysis.com/teamsta ... ortdir=ASC
Some Interesting Articles
Stats in General
http://blog.philbirnbaum.com/2013/06/el ... -than.html
Nazem Kadri being lucky
http://www.theglobeandmail.com/sports/h ... /?page=all
The Toronto Maple Leafs Debate
http://www.grantland.com/story/_/id/979 ... nced-stats
Application of Corsi (blog entry but interesting)
http://www.mc79hockey.com/?p=6267
A paper from the Wharton Business School on the topic
http://www-stat.wharton.upenn.edu/~stje ... t.2013.pdf
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 12:17 am
by bills09
PDO is a stat I look at more than anything.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 2:08 am
by Nick
Only thing more dangerous than ignoring all available information, is using some information incorrectly. A lot of context and sound logic is needed before these in-depth measures will tell you more - to really reach anything useable, finding reliable and valid measures is a first priority, and none of the measures meet strict requirements of prediction. They are great for post-hoc analysis of why something happened- and if the same conditions can be found again, we'd have reason to expect the same outcome but to make a predicative stat (like some say PDO is) takes notably more work to actually be worth a proper 'discussion' in a scientific sense.
Personally I still struggle with the translation of shot attempts (w/ or w/o blocks) to be a good measure of 'possession' - at a team level it has it's uses - as more of the confounds will be randomly balanced out, but at a player level it so full of errors and confounds that finding further value it in is a leap of faith rather than a continuation of logical process (for me).
Now - that doesn't mean I ignore them, and I do follow a several bloggers/writers on the topic - but it's also not why I traded for OEL (just to throw out an example).
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 2:16 am
by Robin Hood
Yea PDO alone is not a strong indicator.
A lot of these stats are not meant to be looked at alone. And PDO in itself is more relevant to the team vs the player, though on-ice PDO has some value.
As far as your comments about Fenwick/Corsi Nick, I think you're underestimating how much predictive power shots have for possession. The gap is that Corsi and Fenwick don't explain everything. However, they are pretty reliable indicators that should be used when building predictive models.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 7:08 am
by Shep
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 7:54 am
by Shoalzie
No stat is fool-proof and only fools use stats as their only proof. It's a way to measure or compare similar things. Stats will tell you what has happened but you can't guarantee it will always happen or happen again. It's difficult to quantify the value of players in team sports when so much of what a player does is dependent on their teammates and their opposition.
Baseball is probably the best sport for the super duper advanced stats given the fact you can track stats off every single pitch. Team sports are tough to single out individuals when players serve different roles in the game itself. You can probably take every goalie and match them up because they do the same thing but then you have to factor in the team in front of them, who they're playing and any other external factors.
Like Nick said, you can put a bunch of numbers in front of someone but they need to know what they mean and why are they important. I want to throw acid in the face of anyone that swears by WAR as the be all and end all stat to determine a baseball player's value when they don't even know what the stat is and how it's calculated. People can say stats are computer driven...well, people make the computers and write the formulas so it's still an objective human thing. I can downplay WAR but a person is using a formula using actual data to calculate what they consider to be a player's value compared to other players.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 8:06 am
by Bruyns
I am a proponent of advanced stats as a way to further my understanding of teams and players, but don't use them to compare player A to player B or to make confident predictions on how a player or team will perform. I think they can be used to identify trends and can be used as a strong predictor for the future, but there are too many factors in play to make concrete predictions and have confidence it will come true.
"Personally I still struggle with the translation of shot attempts (w/ or w/o blocks) to be a good measure of 'possession' "
This was something that I struggled with too since logically to me shot attempts doesn't seem like it should be a proxy for possession. I can't find the article right now, but I read something where someone watched a bunch of games with a stop watch and measured the amount of time teams possessed the puck in the attacking zone. This was then compared to the shot attempt metrics for those games and they lined up showing that those stats did seem to be a perfect proxy for determining which team controlled possession.
Good idea for a thread Shiv, I enjoy discussing this stuff and you can't do it on HF with out all the "haterz" coming out and trying to tell everyone they are wrong without any substance or evidence in their arguments.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 8:47 am
by kimmer
Who's the better player based on WAR shoalzie? Miggy? or Trout?!!?
p.s. sry about the tigers this yr... again
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 8:48 am
by Robin Hood
People should realize btw that the math behind Corsi and Fenwick is spot on. That is not to say that the models are 100% accurate. But the math is correct as an indicator of possession to a level of confidence (there are countless papers on this).
When I talk to most people about advanced stats, these are the points always made:
1. How accurate is Corsi/Fenwick anyway?
2. Stats don't tell the whole story
3. There are flaws in Corsi/Fenwick
4. Possession vs SOG is not the same thing
5. There are intangibles in hockey that advanced stats don't cover
6. Players play different roles in hockey and it is hard to compare Dave Bolland, for example, with Sidney Crosby
While there is some truth to all of these points, there is a level of ignorance in them. Just like Goals, Assists, Points, taken alone do not tell you everything there is to know about hockey, neither do Corsi/Fenwick/PDO. However, they provide models with a certain level of confidence/correlation with what is actually happening on the ice. And they improve how much we know about the game.
There is an incredible amount of bias when you hear fans talk about the game in "subjective" language. I almost puke every time I hear a comment like "He's got a great hands in tight" or "He's one of the best skaters in the league" or "He's a great captain, his leadership is why they play so well". What does that even mean if you really think about it? And we're all guilty of statements like that as fans.
These statements have so much bias built into it. We all fall in love with players that have a "pretty" skating stride, or a good looking wrist shot, or the ability to stickhandle in a phone booth etc. But which players actually win you battles? Which d-men always come out of the corner with the puck/get you out of trouble, for example? Advanced stats help us answer a question like that.
The thing that we are actually trying to accomplish with advanced stats is to answer the question: How much does Player A help you win a hockey game vs Player B? And does building your team one way with Player A, B, C significantly improve your odds of winning a cup than with Player D, E, F.
Advanced stats are helping us answer those guys in a much better way.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 8:49 am
by Robin Hood
Btw, this article on the Leafs last season is a great read. I put it in the original post, but will paste it here again. I disagree with a LOT of what is said but it is a great read regardless:
http://www.grantland.com/story/_/id/979 ... nced-stats
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:13 am
by Bruyns
You left out one of the points made by others that I'm always hearing about recently when people try and dismiss corsi/fenwick as insignigicant or flawed. All I hear now when people argue against possession metrics is SHOT QUALITY and people present arguments about how it's Carlyle's system that only allows teams to take low percentage shots from distance and all Toronto's chances are A+ scoring opportunities so obviously that is why Toronto is having success recently. I don't buy this personally since there has been no evidence to show that Toronto has found this amazing system that only gives them quality shots and not their opponent and no other team in the league is smart enough to employ it.
I read an article recently that argued if Carlyle's system really did suppress the team's shots where they are only taking quality chances and limited the opponents quality chances then you should have seen similar
stats on his Ducks teams that played the same system and this wasn't the case. Toronto is a good team, but placing credit on Carlyle and systems while refusing to acknowledge the impact personnel has made on special teams and the elite goaltending we have received is silly to me. Throw Toskala, Raycroft or Gustavsson in net with the exact same team, system and coaching and I think our record would look a lot different.
The other thing that has bothered me about the Leaf coverage in the media recently is the myth that Reimer is a goalie who is horrible with rebounds and it is a big weakness. It used to be his glove hand everyone jumped all over and now it has transitioned to he can't control rebounds. It seems like no one can admit Reimer is a good goalie and try to nit pick and find something to harp on as a reason he isn't a quality #1. I am happy to have two great young goalies and hate the #TeamBernier #TeamReimer stuff where it appears fans think they have to pick a side and only support one goalie. I hope we get a good return if we trade one and having the media shit all over Reimer's ability when his #s are top notch probably doesn't help his value.
Articles debunking the Reimer can't control rebounds myth:
http://theleafsnation.com/2013/7/15/jam ... d-rebounds
http://www.pensionplanpuppets.com/2013/ ... ier-reimer
http://nhlnumbers.com/2013/7/15/can-goa ... they-allow
I agree with this conclusion from the 3rd article where last season Reimer was 2nd to Rinne in rebound control according to their study:
"Aside from Rinne, who could very well be an outlier here (and we have reason to believe he could be legitimately great at this), there isn't that much a goalie can do in a given year to suggest he has the ability to save more than a few goals. This may be an artifact of the data quality we have to work with. Or it could simply be too difficult for most NHL goalies to control what happens to a very-high-speed projectile after it hits them in the chest."
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:23 am
by Robin Hood
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:24 am
by thom54
omg thank you Shiv and Bruyns.
Props to both of you.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:29 am
by The BBKL Insider
im literally so lazy or busy i dont even run a comparison anymore when talking trade - it's prob why my team sucks
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:31 am
by Robin Hood
Bruyns wroteCOLONYou left out one of the points made by others that I'm always hearing about recently when people try and dismiss corsi/fenwick as insignigicant or flawed. All I hear now when people argue against possession metrics is SHOT QUALITY and people present arguments about how it's Carlyle's system that only allows teams to take low percentage shots from distance and all Toronto's chances are A+ scoring opportunities so obviously that is why Toronto is having success recently. I don't buy this personally since there has been no evidence to show that Toronto has found this amazing system that only gives them quality shots and not their opponent and no other team in the league is smart enough to employ it.
I read an article recently that argued if Carlyle's system really did suppress the team's shots where they are only taking quality chances and limited the opponents quality chances then you should have seen similar
stats on his Ducks teams that played the same system and this wasn't the case. Toronto is a good team, but placing credit on Carlyle and systems while refusing to acknowledge the impact personnel has made on special teams and the elite goaltending we have received is silly to me. Throw Toskala, Raycroft or Gustavsson in net with the exact same team, system and coaching and I think our record would look a lot different.
The other thing that has bothered me about the Leaf coverage in the media recently is the myth that Reimer is a goalie who is horrible with rebounds and it is a big weakness. It used to be his glove hand everyone jumped all over and now it has transitioned to he can't control rebounds. It seems like no one can admit Reimer is a good goalie and try to nit pick and find something to harp on as a reason he isn't a quality #1. I am happy to have two great young goalies and hate the #TeamBernier #TeamReimer stuff where it appears fans think they have to pick a side and only support one goalie. I hope we get a good return if we trade one and having the media shit all over Reimer's ability when his #s are top notch probably doesn't help his value.
Articles debunking the Reimer can't control rebounds myth:
http://theleafsnation.com/2013/7/15/jam ... d-rebounds
http://www.pensionplanpuppets.com/2013/ ... ier-reimer
http://nhlnumbers.com/2013/7/15/can-goa ... they-allow
I agree with this conclusion from the 3rd article where last season Reimer was 2nd to Rinne in rebound control according to their study:
"Aside from Rinne, who could very well be an outlier here (and we have reason to believe he could be legitimately great at this), there isn't that much a goalie can do in a given year to suggest he has the ability to save more than a few goals. This may be an artifact of the data quality we have to work with. Or it could simply be too difficult for most NHL goalies to control what happens to a very-high-speed projectile after it hits them in the chest."
So I do have a counter to your "Shot Quality" argument: The Leafs have the 2nd best PP (28.2%) in the league and the 5th best PK (86.8%) in the league.
I do not believe at even-strength the shot quality argument has any basis. But on special teams, we have been excellent and a LOT of games are decided by special teams.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:39 am
by Bruyns
Agreed and I did reference special teams as one of our reasons for success right now. Our PP has been on point to start this season and the PK success has carried over from last year.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:43 am
by Robin Hood
Bruyns wroteCOLONAgreed and I did reference special teams as one of our reasons for success right now. Our PP has been on point to start this season and the PK success has carried over from last year.
That being said btw, our PP is at 28% at the moment. It was 18% last year lol. There is a potential future regression there though I think Clarkson will help that.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:48 am
by Shep
My hockey mind knows more than any advanced stat will show me.
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 9:59 am
by Bruyns
I like having confirmation for what my eyes tell me when watching. For example last season I felt Bozak wasn't that great and Grabbo was being misused and wasn't playing as bad as his point total suggested. I thought this from watching all the Leafs games, but reading stats and other opinions that come to the same conclusion further supports you aren't crazy and what you saw with your eyes was reflected in the underlying numbers.
I trust what I see too, but having actual evidence strengthens an arguement more than saying "I saw this so I think this" IMO
Re: Advanced Hockey Stats Discussion
PostedCOLON Thu Oct 24, 2013 10:00 am
by kimmer
This is why stat geeks that don't actually watch sports would never understand those intangibles of fantasy sports
someone i remember said it best (not word for word): advanced statistics is a very good tool to put your argument to the needed/necessary point as a supporting device, but it still isn't enough of a contributory factor to base it on as a meat of the argument itself.