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Advanced Stats Thread

Interesting article...A little old.


NHL teams ready to embrace advanced statistics
By Elliotte Friedman Posted: Wednesday, March 6, 2013 | 09:33 PM

few years ago, I was talking to a young player who was really excited after a meeting with his coach. He'd been told he'd scored high on a stat the team kept: how often they retained possession whenever he was responsible for dumping in and chasing the puck.

So, I asked the coach about it. He paused, then smiled and said, "I have no idea what you're talking about." He just didn't want to say anything about this "private" statistic. The next day, the player said, "Please don't report that... I didn't realize I wasn't supposed to say anything."

So it was a secret -- until now.

I've always believed NHL teams keep much more detailed player evaluation tools than they let on. Last weekend, the Massachusetts Institute of Technology hosted its seventh annual Sloan Sports Analytics Conference in Boston. Nicknamed "Dorkapalooza" by ESPN's Bill Simmons, it has evolved into one the most important non-game events on the sporting calendar.

One of this year's panels was entitled "Revenge of the Nerds," about "the meteoric rise and dominance of probabilistic thinking using objective data in decision-making across all disciplines."

It featured Moneyball author Michael Lewis, Dallas Mavericks owner Mark Cuban, and Nate Silver, the statistical genius behind FiveThirtyEight.com. Silver's latest triumph was an astonishingly accurate prediction of the electoral vote count in the recent U.S. presidential election.

Pretty impressive.


Looking for the 'Ah-ha!' moment


Four years ago, the Vancouver Canucks were the only NHL team to go to the conference.

"As we like to say, 'We don't know what we don't know,'" said Laurence Gilman, Vancouver's vice-president of hockey operations and assistant general manager. "What we're trying to figure out is what we don't know. This conference helps get us thinking in ways in which we weren't thinking."

Meanwhile, the Edmonton Oilers' Kevin Lowe and Craig MacTavish attended for the first time this year.

"It was thought-provoking," MacTavish said.

This year, Boston, Dallas, Edmonton, Tampa Bay, Vancouver and Washington were there. Technically, Anaheim attended too, although Brian Burke spent more time ripping statistical analysis than praising it. I couldn't stop laughing at his quotes ("Statistics are like a lamp post to a drunk: Useful for support but not for illumination"), picturing how much attendees wanted to strangle him.

"It's not only about analytics, but the critical decision-making process," said Don Fishman, the Capitals' assistant general manager and director of legal affairs, attending for the third time. "That's why I love it...You learn what other leagues and teams are going through to make the decisions they need to make."

"There was a panel talking about football decisions, in-game probabilities," he added. "They were going through plays -- if you have the lead and the ball on your own 40-yard-line with with under five minutes to go, the probabilities may be better to retain possession. [Former New York Jets and Kansas City coach] Herm Edwards was saying, 'Twenty years ago, you'd never think about it.'"

"Everyone wants a black-and-white answer: Will a trade work or not? Nate Silver said analytics won't provide that... You can't do that in sports. But they might let you know if there's a 60 per cent probability whether something will work. So, you can determine if there is a better chance the trade will succeed for you."

"There's a ton of data out there," MacTavish said. "How are you going to use or make it work for you? A little edge in today's game goes a long way. We're all looking for the 'Ah-ha!' moment, but no one's found it yet."

"If you're playing blackjack and you've got 15 while the dealer has a nine, you hit on that," said Stars assistant general manager Frank Provenzano, attending for the second time. "You might get a 10, but you still do it to shift the odds in your favour. I'm looking for the hockey equivalent of that."

"Can we uncover something of value? Something someone else doesn't have?"


Not the most statistic-friendly sport

The biggest problem for the NHL is the sport just doesn't have the statistical bent of others.

"We are third, behind baseball and basketball," Fishman said.

So teams are creating their own. Because there is no consensus, they are notoriously secretive. One thing I believe some teams do is remove "second assists" from players and see how many points are left over. But good luck trying to confirm that.

"We're looking to determine what is random, and what is true performance. Other than that, I'm not going to tell you what we do," Fishman laughed.

"This is a competitive business and sports analytics is untamed territory," Gilman says. "When people were out there discovering a new world, they didn't want anyone else to know what they were doing."

"But believe me when I tell you there are percentage results that allow you to coach and manage your team to hedge bets in certain events."

"Do we have a formula to evaluate players?" Provenzano pauses. "We do... And the question is do we have confidence in it to apply it yet? Not really ... We're working to get models that are more predictive at a higher confidence."

"Each variable has an element of error to it. That starts to add up, so it's full of uncertainty. The Holy Grail is to... find a model that brings you more goals and more wins."

More than just stats

One of the biggest issues with analytics is that its most hardcore followers tend to discount things like "heart" or "clutch performance" because they are not quantifiable. That's a bad idea in hockey, which is so highly dependent on one-on-one battles. Meanwhile, Oakland A's general manager Billy Beane, the hero of Moneyball, blamed his team's playoff failures on "luck." That's a cop-out.

"If you rely solely [on analytics], you do it at your own peril," says MacTavish, who played 1,093 NHL games. "Nobody's figured out a fail-safe method, not in baseball, football, hockey or soccer. But you're foolish not to be [looking at them], either."

Fishman and Gilman are lawyers. Provenzano has a masters' degree in business administration. They are trained to think logically and follow a process. But they aren't automatons. They agree the best way to succeed in the NHL is a marriage of statistical analysis and "feel," for lack of a better term. Provenzano's boss is a Hall of Famer who won three Stanley Cups and scored 564 goals. If anyone should understand what makes a hockey player, it's Joe Nieuwendyk.

Does he listen to analytical advice?

"He's open to it," the assistant says. "Like anyone sitting in [the GM's] chair, he will use it if what you're proposing makes sense."

"Can someone skate? Is he smart? These are things you can't capture numerically. But if he can do those things, then you plug his performance into a model and more good things happen than bad, that helps you."

Teams are trying to apply this to everything from what happens during a game to evaluating potential draftees to valuing free agents. Washington, for example, has a decision to make on Mike Ribeiro.

"You look at statistics, you look at age, you look at probabilities," Fishman says.

He does the contract work for the Capitals and it would be a stunner if every team in the NHL wasn't doing some variation of the same thing. The Oilers, for example, meet monthly with a volunteer "analytics advice group." It's led by Dan Haight, COO of Darkhorse Analytics and managing director for the University of Alberta's School of Business.

"It is amazing, the passion these people have for hockey and the Oilers," MacTavish said. "It's definitely led to philosophical conversations about what we should be doing. A bunch of people talking about different ways of doing things leads to innovation. It's good to surround ourselves with people who are rarely thinking like we are."

"I thought our guys would be at the top echelon of presenters [at the Sloan Conference]."

Edmonton runs a contest on the team website -- "Last Fan Standing." Basically, you choose a game on the schedule and answer five questions about it. The questions are pretty detailed:

"Will there be a penalty call for hooking?" "Will both teams combine to score six or more goals?" "Will the final goal be scored in the third period?"

The more correct answers, the more opportunity to enter prize draws. But is there something extra to this contest?

"You're always looking to flush out some brainpower," MacTavish says.

http://www.cbc.ca/sports-content/ho...ams-ready-to-embrace-advanced-statistics.html
 
Why corsi/possession should not be the goal

Let’s imagine a sport where two factors are equally correlated with winning so that FactorA is 50% correlated with winning and FactorB is 50% correlated with winning. Now for years general managers in this sport only ever knew that FactorA existed and when choosing how to build their team they only ever considered FactorA. Now let’s assume that in this idealist, yet uninformed about FactorB, world every general manager of every team allocated their financial resources perfectly based on their knowledge of Factor A. On top of that, every team is working under the same financial constraints meaning they spend the exact same amount of money.

The result is, in this fictional world, FactorA becomes perfectly evenly distributed across every team. Strangely though, even after accounting for luck, teams have statistically significant differences in winning percentages.

Now, along comes a smart individual who discovers the existence of FactorB and finds out that FactorB correlates 100% with winning percentage (after factoring out luck) and concludes that General Managers were wrong all along and that FactorB is all that matters to winning and FactorA is irrelevant (has to be since it has zero correlation with winning). Upon discovering this he gets hired to become a General Manager of a team and while every other GM was only signing FactorA players he chose to go out and sign solely FactorB players. He made signing FactorB players his goal. Strangely, despite FactorB seemingly showing a 100% correlation with winning, his team didn’t win any more than anyone else.

The reason for this is that FactorA is in fact important. It just doesn’t seem important because everyone knows about FactorA and FactorA is getting evenly spread out across teams. Ignoring FactorA for FactorB is equally wrong as ignoring FactorB for FactorA. Upon learning of the existence of FactorB and its high correlation with winning, the goal of a General Manager is not to optimize his team for FactorB but to recognize that there is undiscovered value in players that have FactorB as a skill while not ignoring other skills that we previously knew existed.

Bringing this back to hockey, lets call FactorA shooting percentage and FactorB shot generation. Teams have typically doled out contracts based on shooting percentage but not based on corsi as shown by Eric T. His conclusion was:

"most teams don’t give out contracts because of Corsi. But a team that does will get more wins out of their budget than a team that follows the conventional path and overvalues finishing talent"

My response is, not if it comes at the expense of ignoring finishing talent. Based on Tom Awad’s work, finishing talent is probably at least 50% of out scoring your opposition (note that shooting percentage is a combination of out finishing and shot quality in Awad’s terminology).

So, if teams have been doling out contracts based on, effectively, shooting percentage then it is perfectly reasonable to assume that shooting percentage talent is more evenly distributed across teams than corsi-talent is. Under these circumstances corsi would be highly correlated with winning percentage because that is where the differences lie between teams. This doesn’t mean that corsi is the main factor in out scoring the opponent though and valuing corsi at the expense of shooting percentage will be a detriment to any General Manager.

Furthermore, if General Managers as a whole started paying primarily for corsi we will start to find that corsi talent becomes more evenly distributed across teams and thus shooting percentage would become much more highly correlated with winning (even after adjusting for luck). Furthermore, paying players based on corsi would potentially lead to players altering their style of play to optimize their corsi statistics to the detriment of the ultimate goal, out scoring the opponent.

It is certainly possible in the current hockey universe in which players are paid more by shooting percentage than corsi that they play a style of game to optimize shooting percentage at the expense of winning so it is not unreasonable to see the flip side occur of corsi because a metric by which general managers dole out contracts.

Ultimately, the goal of any General Manager is to optimize his line up for out scoring the opposition, not out shooting percentage-ing them and not out corsi-ing them. Corsi or possession should never be considered the goal just as shooting percentage or any other identifiable skill shouldn’t be. The goal has been, is, and always will be out score the opposition and it’s the General Managers job to find the right balance of all the identifiable skills, not just those that seemingly correlate with winning.

http://hockeyanalysis.com/
 
This one Leafs fan watched every minute of every Leafs game from the first half of last season with a stop watch to track actual possession. And he found that his numbers were nearly identical to the CORSI/FENWICK numbers tracked by sites like behindthenet. His conclusion was that corsi/fenwick are in fact a good proxy for possession.

It was a small sample size though. He tracked just one team in a short season.

The other issue (and where a lot of these guys go wrong) is that he assumes that bad possession teams can't experience success long term. While possession is an important indicator of success, it isn't the only indicator. It's just one of many. It's like saying you can't win without great goaltending. It's easier to win with great goaltending, but it's not a exact predictor of success.

The link:

http://www.pensionplanpuppets.com/2013/9/16/4727746/leafs-attack-time-at-the-halfway-mark
 
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This one Leafs fan watched every minute of every Leafs game from the first half of last season with a stop watch to track actual possession. And he found that his numbers were nearly identical to the CORSI/FENWICK numbers tracked by sites like behindthenet. His conclusion was that corsi/fenwick are in fact a good proxy for possession.

It was a small sample size though. He tracked just one team in a short season.

The other issue (and where a lot of these guys go wrong) is that he assumes that bad possession teams can't experience success long term. While possession is an important indicator of success, it isn't the only indicator. It's just one of many. It's like saying you can't win without great goaltending. It's easier to win with great goaltending, but it's not a exact predictor of success.

The link:

http://www.pensionplanpuppets.com/2013/9/16/4727746/leafs-attack-time-at-the-halfway-mark

I think he's just being honest in that if you combine the Leafs' terrible Fenwick/Corsi numbers and the fact it was a shortened season, the most likely explanation was that the Leafs were "lucky" last year to get into the playoffs. I can't stand the guys who are so adamant it's the case, but there's nothing wrong in making that assumption for the time being.

If the Leafs make the playoffs this year with terrible advanced numbers, then we can start making a case for finding the flaws (which definitely exist, just a matter of finding them).
 
I think he's just being honest in that if you combine the Leafs' terrible Fenwick/Corsi numbers and the fact it was a shortened season, the most likely explanation was that the Leafs were "lucky" last year to get into the playoffs. I can't stand the guys who are so adamant it's the case, but there's nothing wrong in making that assumption for the time being.

If the Leafs make the playoffs this year with terrible advanced numbers, then we can start making a case for finding the flaws (which definitely exist, just a matter of finding them).

It's not just about flaws though. The Leafs need to improve the possession side of their game, but that doesn't mean they can't have success if they don't.

I'm a big proponent of Fenwick -- but it isn't an exact predictor of success. Teams like Pittsburgh, Anaheim, Washington, Toronto etc all had relatively successful years with average to below average possession numbers. It wasn't like the Leafs were the only below average possession team to find success.

If you're good enough in other areas, you can overcome below average possession stats.
 
It's not just about flaws though. The Leafs need to improve the possession side of their game, but that doesn't mean they can't have success if they don't.

I'm a big proponent of Fenwick -- but it isn't an exact predictor of success. Teams like Pittsburgh, Anaheim, Washington, Toronto etc all had relatively successful years with average to below average possession numbers. It wasn't like the Leafs were the only below average possession team to find success.

If you're good enough in other areas, you can overcome below average possession stats.

Yeah good in other areas, or lucky (see PDO). I'm totally on board with the idea that they're not the be-all-end-all, especially when it comes to the Leafs one factor that gets ignored is despite the ugly advanced stats, they're a young team that will more than likely grow and get better.

And another thing I noticed from the super-advanced stats supporters was that despite David Clarkson's long contract, his advanced stats are pretty good, but they seem to have ignored them (and boast about Grabo while they're at it).

This season will tell us a lot going forward.
 
The Leafs must be the luckiest team ever, because they finished 6th in shooting % the year before last. The Leafs finish at the top or near the top in shooting %, because they have a lot of offensive talent.

That is a good point that's been ignored this offseason. The Leafs have added a couple good possession guys in Clarkson and Bolland, and they should have Gardiner/Lupul for most of the year and those 2 are good possession guys as well. It's an area where they should be vastly improved.
 
Not to mention addition by subtraction. Not having Holzer, Kostka, and hopefully Fraser in the lineup on a regular basis should help too.
 
I don't like to disregard the possession stats, but sometimes you have to step back and see what you're actually predicting.

What the Corsi addicts are actually predicting about the Leafs this year is:

1) The Leafs' offense significantly overachieved last year. The thing is, best on previous years' production, they really didn't. They had a couple of surprises (Kadri, Franson) and some dissappointments (Grabo, Lupul, Gardiner, Liles) but overall scored at about the expected level. Predicting them to drop significantly offensively is probably a bad prediction regardless of shooting percentage, especially considering the fact that key offensive players like Lupul and Gardiner will most likely play significantly more this year.

2) The Leafs' goaltending significantly overachieved last year. The thing is, Reimer didn't do anything other than repeat his performance from his last healthy year in his rookie season. Predicting him to get significantly worse is probably not a great idea, especially with Bernier there as an extra layer of insurance if he does.

The corsi addicts are avoiding actually making the above 2 arguments, though, because they're much harder to make, and are instead hiding behind the possession stats from a shortened season and refusing to make any further analysis - and that's pretty telling.

Moreover, there's a third argument which only recently have they started to address in their predictions, as a bit of a copout preemptive excuse:

3) That the leafs' offseason changes did not improve the team, and actually made them worse. I've seen more predictions recently with the copout "UNLESS they significantly improve their Corsi", so at least they're starting to realize this one glaring weakness of their arguments so far. But we know this is a copout because with all the crying over losing Grabo's Corsi, and criticisms of Bolland's Corsi, we know that they have to be predicting the Leafs should be getting even worse Corsi-wise....but again, they won't actually go so far as to say that, because they know it's much harder to defense. More telling is that you never hear about the positive Corsi of additions like Clarkson and Gardiner....in fact, the Corsi crowd lambasted the Clarkson signing DESPITE his great Corsi, which is the most telling of all. But we can't let them copout on this one, because the necessary conclusion from all their arguments offseason is that these changes made the Leafs worse, not better, even if they refuse to actually come out and say it:

Scrivens ----> Bernier

Kostka ------> Gardiner
Holzer ------> Ranger
(Liles -------> Rielly?)

Frattin -----> Clarkson
Grabo ------> Bolland
MacArthur --> Raymond
Komarov ----> Colborne/Ashton
 
Taking a closer look at the fenwick numbers, the Leafs were better from an offensive standpoint than the overall numbers show.

The Leafs ranked 19th in missed shots directed towards the opponents goal and 26th in shots that hit the opponents target. Not great but not the absolute worst. But it's the defensive side of things where they ranked right at the bottom. The Leafs ranked 30th in missed shots directed towards their goal and 29th in shots allowed that hit the target.

It wasn't really about the ability to create offense, they were just allowing too many chances. Holzer was a complete disaster and he posted one of the worst Corsi's in league. Fraser, relative to the comp he faced, was not effective as well. I think the biggest difference will be Gardiner, who posted one of the best Corsi's in the league last year. A more mobile, puck savy blueline will go a long way in correcting possession related issues next offseason.
 
if you have time see if you can find it - pensionplanpuppets (I think) wrote up a post criticizing Carlyle's "defensive system", and inadverdently showed clearly that the increase in shots against under Carlyle came entirely from an increase in long distance shots. they didn't even notice what they had done - they didn't even realize that the "negligible" decrease in shot from in close was actually fairly significant, percentage-wise.
 
Something is missing here.

12/13: 1st in Shooting % / 6th in Goals For
11/12: 6th in Shooting % / 10th in Goals For

I don't buy this 'lucky' argument because just the year before the Leafs were top 10 in shooting % and goals for as well. I find it very unlikely that the Leafs got 'lucky' over 130 games from an offensive standpoint. It's just too big of a sample size.

I think the increase in point production from 11/12 to 12/13 was based mostly on the massive increase in SV%. That alone accounts for a large portion of the point increase.

How are the Leafs able to score as many goals as they have over the last two seasons, but rank so poorly in Fenwick/Corsi. It's tough to figure out.
 
Something is missing here.

12/13: 1st in Shooting % / 6th in Goals For
11/12: 6th in Shooting % / 10th in Goals For

I don't buy this 'lucky' argument because just the year before the Leafs were top 10 in shooting % and goals for as well. I find it very unlikely that the Leafs got 'lucky' over 130 games from an offensive standpoint. It's just too big of a sample size.

I think the increase in point production from 11/12 to 12/13 was based mostly on the massive increase in SV%. That alone accounts for a large portion of the point increase.

How are the Leafs able to score as many goals as they have over the last two seasons, but rank so poorly in Fenwick/Corsi. It's tough to figure out.

When pressed on the issue, people who argue high shooting percentage as a reason the Leafs got "lucky" have a hard time pointing to which players specifically they can expect a regression on. Other than Kadri, the other players have performed point wise at the levels they did last year before and for long stretches.
 
Leafs just have guys with good career shooting percentages:

Kessel 10.9
Lupul 11.5
Kadri 14.0
Bozak 15.5
VanR 10.7
Clarkson 9.4
Bolland 14.4
Kuly 12.0
Raymond 9.5
McClement 8.8
McLaren 11.1
Orr 7.5
Colborne 8.3


Phaneuf 6.2
Gardiner 7.7
Franson 6.0
Liles 6.9
Gunnarsson 5.2
Ranger 5.2
Fraser 4.1
 
The Leafs have 9 forwards who are capable of 20+ goals, none of which would be surprise if they get to that level.

The Leafs will be one of the top scoring teams in the league again, because they have elite talent and good depth.
 
The Leafs have 9 forwards who are capable of 20+ goals, none of which would be surprise if they get to that level.

The Leafs will be one of the top scoring teams in the league again, because they have elite talent and good depth.

When was the last time a team had 9 forwards with 20+ goals? It's tough because there's only so much PP time to go around. And the Leafs don't typically use a forward on the point of the PP.
 
When was the last time a team had 9 forwards with 20+ goals? It's tough because there's only so much PP time to go around. And the Leafs don't typically use a forward on the point of the PP.

Sometime in the 80s?

Maybe in that first post lockout year?

But he didnt say ALL would get that...just that none would shock if they did.
 
Last 2yr Goal Paces:

1 Kessel 36
2 Lupul 36
3 Clarkson 29
4 Kadri 27
5 JVR 26
6 Bozak 21
7 Bolland 19
8 Raymond 16
9 Kulemin 10 (McClement 12)
 
When was the last time a team had 9 forwards with 20+ goals? It's tough because there's only so much PP time to go around. And the Leafs don't typically use a forward on the point of the PP.

I'm going to guess that it was the Cup winning Rangers team from the 90's. I remember them having a pile of 20+ goal scorers.
 
So the only two guys that haven't actually already had 20+ goals in a season before are Bolland (19) and Kadri (18 in a shortened season)?

Not bad.
 
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