Showing posts with label Pittsburgh Penguins. Show all posts
Showing posts with label Pittsburgh Penguins. Show all posts

Saturday, February 16, 2013

On the Justification of Matt Cooke Escaping Supplemental Discipline

When Brendan Shanahan succeeded Colin Campbell as the NHL's chief disciplinarian in June of 2011, the change was fueled by widespread criticism of the latter's tenure, culminating with the leak of certain emails he composed in 2006 and 2007. Already under fire for his inconsistency when handing down suspensions, Campbell's emails worked as additional evidence of biases preventing the proper function of the position to be achieved.

Shortly after Campbell stepped down, Shanahan acknowledged that the goal behind supplemental discipline is "player safety," and has since followed through on his pledge for decision-making to be done in a more uniform and transparent manner. More or less, Shahahan wanted to shift away from Campbell's general ambiguity regarding whether or not a play would receive attention from the league, instead making it widely known why or why not certain conduct would be considered and/or deemed suspendable. In the brief period we've known the "Shanaban" to be in existence, whether or not we agree with the final ruling, Shanahan's videos explaining the reasoning behind every decision have certainly worked to create a more uniform understanding of what the league is looking at in each case.

Enter: Matthew David Cooke.

By now, we've all formed an opinion on the controversial play that occurred during the second period of Wednesday night's game between Ottawa and Pittsburgh. Whether or not one believes that Matt Cooke acted with the intent to injure Erik Karlsson, those charged with deciding whether supplemental discipline was warranted ultimately concluded intent to injure was absent in this case.


For many, this was a suitable end to what was commonly deemed a "hockey play." However, a rather curious word appearing in the reasoning from the NHL and others alike is that of "intent." Granted, it is admittedly difficult to establish intent on a play like this because of the general speed of hockey and how fast things happen at ice-level. Nonetheless, is Cooke's intent something we should be worried about here? The following video points out the validity of such a question:



Using the standard format adopted since becoming the Director of NHL Player Safety, Shanahan goes through an analysis of an illegal check by Colin McDonald on Ben Lovejoy. After determining that McDonald was guilty of boarding, Shanahan candidly admits that he accepts McDonald's assertion of no malicious intent. What is more, Shanahan explains that McDonald's intent is immaterial because it is a "reckless and dangerous play." Running through the other factors commonly considered, he notes that there was no apparently injury and that McDonald has no prior history of discipline.

Moving back to the standard of culpability, if intent was immaterial when suspending McDonald because his conduct was "reckless," why is it suddenly required to discipline Cooke? Moreover, if the league is implying that intent, rather than recklessness, must be the standard for a play to be adjudged illegal after the fact (which doesn't seem to be the case), the league's justification for Cooke escaping supplemental discipline is yet another chapter in a library of inconsistent rulings. We can infer that the Department of Player Safety doesn't believe Cooke to be guilty of their first element, e.g. a rules infraction, but the absence of a clear articulation of such a position is rather illogical.

In other words, why speak to Cooke's intent when it should be immaterial? Though intent to injure is difficult to prove here, can the same be said for recklessness? The league must have felt so, noting that the decision for Cooke to escape supplemental discipline also included the absence of a hearing.

In a video that’s gained praise for establishing how common these sorts of plays are, TSN's Aaron Ward cites two examples from the first period of Wednesday's Dallas at Calgary game, where players go for what he calls a "hit and pin," similar to Cooke's check on Karlsson.

However, after watching the video, there was a noticeable difference between Cooke's attempt and the others that were examined. Rather than establish an absence of blame for Cooke's conduct, Ward's examples actually helped explain just how dangerous the check actually was.

Consider the following images:



When contact is initiated between Cooke and Karlsson, both players are heading toward the boards as they try to retrieve a loose puck. Karlsson's position includes the gap between his legs necessary to pin a player, seemingly Cooke's intention bearing in mind the position of his left leg.




Before the players make contact with the wall, Cooke's right skate is positioned at the same angle of the first image above, while the gap between Karlsson's legs has narrowed, a result of their battle for position. However, Cooke's left skate has risen from the ice, and his skate blade is noticeably at a much wider angle than before, almost parallel to the boards. A bit of a peculiar line to take rather than establishing a pin by pointing his foot at a 90 degree angle to the boards, situated to the left of Karlsson's right leg. Even so, should the two contact the wall in this position, all of this is likely of little concern.




However, the moment Karlsson reaches the wall is where the issue develops. Cooke's skate still remains at a wide open angle rather than pointed at the "GH" in "Highmark" along the boards, and has actually reached its highest point above ice level. Karlsson's legs have slowly closed prior to impact, the gap required for a pin now removed. Whether it was Cooke's decision or natural reaction to channel his inner Captain Morgan, his skate being parallel to the boards instead of pointed toward them has put Karlsson in a vulnerable position should it contact the unprotected back of his legs.


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Unfortunately, that's exactly what happens. There remains a wide disparity between the angles of Cooke's left and right skates, and Cooke's failure to place his left skate between either of Karlsson's results in his blade contacting the back of Karlsson's left Achilles. An unfortunate result to an unfortunate play, but just how common is something like this?


Let us move to Aaron Ward’s breakdown below:



Right away, we see that Ward's first example of a "hit and pin" involving Dillon and Stempniak is markedly dissimilar to when the contact initiated between Cooke and Karlsson. Rather than having both players engaged with one another and gliding into the boards together, Stempniak is already close to the wall as Dillon approaches from a distance. Stempniak also has neither his back turned, nor the unprotected back section of his legs vulnerable to a skate blade.




Stepmniak then plays the puck around the end-wall, while Dillon goes for the "pin," which seems to resemble more of a standard body check. Regardless, notice where Dillon's skates are compared to Cooke's just before impact.




The noted whirling dervish that he is, Stempniak jumps out of the way of the check. It is only after Dillon contacts the wall that his skate rises above the yellow.


Example number two involved Dennis Wideman making a pin attempt as he skates in, also from a distance:



The difference between this hit and Ward's first example is that the Dallas player gets the puck tangled between his legs, meaning the disc wasn't moving prior to contact as with Dillon's missed check.




Once he receives the puck, the gap between his legs necessary for a pin is exhibited.




Again, just prior to contact, both of Wideman's skates remain on the ice. Wideman then moves into position to establish the pin.




It is only once contact is made and the puck battle is established that Wideman's right skate comes above ice level, again nowhere near as high as the skate that injured Karlsson. What is more, his blade is at a 90 degree angle to the wall, ensuring the Dallas player is in no danger of unnecessary injury.


Though it is inarguable that pinning a player along the wall happens during every NHL game, it does not follow that Ward's examples absolve Cooke of wrongdoing. Whether or not Cooke intended to hurt Karlsson, there is an argument to be made that Cooke's reckless positioning of his left leg and skate blade worked to put Karlsson in a vulnerable situation, as opposed to the examples of Dillon or Wideman. Perhaps conduct similar to Cooke's is more common than Ward's illustrations seem to suggest, but players have engaged one another heading into the boards with few similar resulting injuries to-date.

It is true that we don't know whether Matt Cooke intended to hurt Erik Karlsson. However, it is rather evident that the way he approached his check doesn't seem to do Karlsson many favors, while the league's sudden fixture with Cooke's intent ignores a play with the signs of reckless conduct. If the Department of Player Safety doesn't want to suspend Cooke, that's ultimately their call. However, relying on his failure to meet a level of culpability that until now hasn't been required, all the while refusing to grant a hearing when signs of recklessness could be established, Karlsson suffered an injury on the play, and Cooke has a lengthy prior history, is unjustifiable.

Brendan Shanahan was supposed to help rid ambiguity from the NHL's administering of supplemental discipline. However, if the standard of review is constantly in flux, the NHL's "wheel of justice" shall live long and prosper.

Sunday, June 24, 2012

Sunday Night Links (6/24)

Welcome to the first installment of Sunday Night Links, a new feature here where we list a few articles we find noteworthy from the previous week.  Discussion is obviously encouraged, and if there's something you want to add, feel free to drop us a line either here or on Twitter.

Without further ado:

What has been most interesting to me is the next chapter in the ongoing Rick Nash saga, and how Ray Shero's handling of Jordan Staal is an example of a general manager who understands asset management and how to maximize value in an awkward situation.  Howson's intransigence has cost his team a substantial amount of value, and his decision to pass on moving him at the deadline has just been matched in stupidity by the decision to wait until July. 

Saturday, April 28, 2012

Devils - Flyers Podcast Preview

In this two-part preview, Chase, Corey from Shutdownline and I were joined by friend of the blog Geoff Detweiler from Broad Street Hockey to talk about the gong show that was the Pens - Flyers series and the Flyers' second-round matchup against the Devils. Chronology be damned, we also talked about the Devils side with our own Triumph less than an hour after their game-seven win over Florida.



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Wednesday, April 11, 2012

Playoff Preview Podcast: Penguins - Flyers

This time Triumph lead the surprisingly civil discussion of the Pittsburgh - Philadelphia series. We were joined by gentleman, scholar and Flyers blogger Eric T. (@BSH_EricT) from Broad Street Hockey.

Just as a programming note, Brent (Triumph) is your host and Chase is chiming in with comments about both the Flyers and the Penguins. His official prediction stands at Flyers in four.



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Thursday, April 5, 2012

Darren Dreger Would Be Squandering His Vezina Vote

Last night, TSN hockey insider Darren Dreger sent out a tweet that has rightfully raised eyebrows within the analytical hockey community. The message reads:


When questioned on the matter, Dreger responded with the following:



Speaking to his first remark about consistency, Dreger does have a bit of a point here; Fleury has consistently been a below average goaltender this season. For the 2011-2012 campaign, Fleury's even-strength save percentage is .914, markedly below the league-average number George E. Ays shows us here:


Though Broad Street Hockey's Eric T. points out that overall save percentage may be a better predictor of a goalie's future success in the short run, i.e. over one season, he also shows that ESSV% is the better predictor over large samples. Lucky for us, we have even-strength data going back to 2003-2004 pour la fleur. The results are as follows:

YearES SavesES Shots AgainstESSV%
2011-2012130414260.914
2010-2011129614010.925
2009-2010125613830.908
2008-2009131014210.922
2007-20086436840.940
2006-2007130314220.916
2005-200693810260.914
2003-20044495000.898
Total849992630.918

Even if we throw the best indicator for Fleury's future success out the window, his overall save percentage this season is 0.913 which still falls below league average. Without digging up the precise numbers, this tweet from draglikepull sums up the point perfectly:


Unfortunately, Mr. Dreger seems to have fallen for the same illusion that so many in the mainstream media have before him. Marc-Andre Fleury has no business in a discussion for the Vezina trophy this season, last season, or likely in any season going forward. Good coaching, strong possession metrics and the ability to keep the play as far away from The Flower as possible are what have kept the Penguins afloat amidst their run of injuries.

In sum,

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Wednesday, March 28, 2012

The Driving Play Podcast - 2012 Playoff Race Edition

Good evening, friends. We're back again with another edition of the Driving Play Podcast, this time discussing the tight playoff races in the Eastern and Western Conferences. We are happy to be joined by Corey Sznajder of the Carolina Hurricanes blog Shutdown Line. Just as a production note, we recorded this podcast yesterday before Buffalo's win over Washington, the Pens losing to the Islanders and the Rangers beating the Wild. Small sample sizes and having confidence in Dale Hunter can be cruel mistresses.

Enjoy.



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Saturday, February 25, 2012

Driving Play Podcast - Take Three & Fore(checker)

The latest two additions of the Driving Play podcast come in a bit of a somber mood. We had originally recorded an extensive chronicling of the Western Conference buyers, but like your favorite European in the playoffs, Jared's hard drive couldn't handle the pressure and gave out on us.

In addition to the excellent discussion we had with Geoff Detweiler of Broad Street Hockey about the buyers of the East, we luckily salvaged an interview about the Nashville Predators with another of our favorite bloggers, Dirk Hoag of On the Forecheck.

Below are the third and fourth editions of the Driving Play podcast, first with Geoff and then the interview with Dirk. Enjoy.

Eastern Conference Buyers




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Discussing the Predators with Dirk Hoag




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Sunday, November 20, 2011

Anomalies: Why Are Crosby's Possession Numbers Merely Good

This will perhaps be the start of a continuing series in which we analyze and discuss strange things we've noticed about hockey statistics. A feature of these articles is that we won't have all the answers, so comments and discussion are strongly encouraged.

In this installment, I want to discuss something that has irked me since I first got into hockey analytics. After reading about Corsi and Fenwick stats I went to BTN to look at the numbers for my favorite team, the Pittsburgh Penguins. I was quite surprised by how bad the team was according to these metrics, this was in the Therrien days, and in particular Crosby's numbers were downright mediocre. They have improved since but over the last two seasons, in which he played a season and a half, his even-strength Corsi/Fenwick stats are merely good instead of great. To state the obvious, he is considered by many to be the best player in the game and nobody reasonable would put him outside the top 5-10 players, head injury aside. What gives?

5-on-5 Corsi

Here are his Corsi numbers from 2007-2008 through 2010-2011. I include his rank among forwards that played 40 games or more for the given year.

SeasonCorsi On/60Rank
2010-20118.5564
2009-201012.5529
2008-2009-0.21186
2007-20082.35140

Even with the improvement, including the huge points streak taking up much of the 2010-2011 season, you can see that his stats aren't close to the elite level most everyone would put him at, including us nerds. I have a couple possible explanations, but would love to hear from you if you've got more.

Weak Linemates

For Pens fans, a frustrating part of having so much strength at center is that there is not a lot of money to go around for wingers. If you look at the guys consistently at the top of the Corsi rankings, you tend to see pairs or groups of top guys that play together or perhaps an elite player with at least one good player. Examples include a number of Detroit combinations, whichever combination of Kane, Toews, Sharp and Hossa you like, the Sedins, Ovechkin with Bäckström and Kesler with Raymond. Crosby has spent most all of his time with guys like Dupuis and Kunitz who aren't bad but are definitely role players and don't compare well to those names.

Let's take a look at the Corsi QoT for selected players in the last 3 full seasons. Corsi QoT is the average Corsi rating off all skater teammates for the player's ice time. It isn't perfect because a player influences his teammates' ratings but gives a rough idea how good the teammates are.

Player2008-20092009-20102010-2011
Sidney Crosby-3.6285.2975.779
Alexander Ovechkin12.9538.4384.013
Pavel Datsyuk17.24612.2297.363
Jonathan Toews11.62914.8588.437
Henrik Sedin1.3687.4358.28
Ryan Kesler-0.1497.0217.624

You can see that going by this metric Crosby's teammates have not been as strong as those of other elite players.

An exception to this rule is that he has played a bit of time with Malkin. How has that duo been? I haven't pulled data from 2007-2008, but I do have it from the last three years. Here is a chart with their Corsi rates together. Unsurprisingly, they are all much better than Crosby's overall numbers.

YearCorsi%Corsi/60Minutes
2008-200947.5%-5.647393
2009-201056.2%16.377202
2010-201162.0%32.047163
Total53.4%8.317758

I'll have more on that 2008-2009 season in a bit, but in the last two years for the time they've been on the ice together they have dominated. I didn't list the score-tied numbers but they are actually pretty similar.

Coaching

People are making similar arguments for Ovechkin this year, which I think is at least in part an overreaction to some brutal shooting luck, but it seems like in the early years the cautious, defensive approach espoused by Michel Therrien may have held the Penguins back. It's beyond my area of expertise to analyze the particulars of this, but there are data to back this up.

Courtesy of time on ice here are the Corsi percentages (Corsi shots for divided by Corsi shots for and against) the seasons before during and after Bylsma took over for Therrien. While the Pens were and still are a young team, the jump is pretty big and the 2008-2009 season is damning.

SeasonCoachCorsi%
2007-2008Therrien45.6%
2008-2009Therrien46.0%
2008-2009Bylsma52.8%
2009-2010Bylsma52.2%

A problem with this analysis for the 2008-2009 season is that Gonchar, Pittsburgh's best defenseman that year, was out most of the early part of the season coming back right around the time Bylsma took over 25 games from the end. Here are the numbers from 2008-2009 for all time in which Gonchar was off the ice, whether or not he was in the lineup, under Bylsma and Therrien.

CoachCorsi%
Therrien46.0%
Bylsma52.8%

For that 2008-2009 season, here are Crosby's on-ice Corsi numbers with each coach:

CoachCorsi%Corsi/60
Therrien48.8%-2.836
Bylsma50.5%1.205

Of course there are many many other factors like overall team skill going up and variance may have played a role. That said, based on these splits I think some of the blame for the first couple years goes to Therrien, or you might say the praise for the last few goes to Bylsma.

Putting It Together

Let's look at Crosby's Corsi numbers with and without Malkin since Bylsma took over:

SituationCorsi%Corsi/60
With Malkin57.7%20.239
Without Malkin53.0%7.12

That's in 421 minutes of ice time with Malkin, or over 7 full games worth of time. If Crosby played 75% of his time with Malkin then his Corsi% would be about 56.5% and his rate about 17. Both of these numbers would be right up at the top of the Corsi rankings.

Conclusion

These are my ideas, I'd love to hear more if you've got them. I'd also be interested in your thoughts on what I'm putting out there. I think the biggest factor by far is the relative weakness of the wingers. This is supported by how dominant Crosby was when Evgeni Malkin played the top-winger role for him over the last couple seasons.

Tuesday, October 25, 2011

On the Chris Kunitz Extension

Since there is no time like two weeks after it was signed, let's take a look at the Chris Kunitz contract extension.

The Terms

Kunitz's current cap hit of $3.75M was extended for another 2 years with salary to match. There are a couple things to note about this. For one, it was signed at the start of the season, a practice Triumph discussed in a recent post. From the Pens' perspective, this opens them up to risk in case Kunitz gets an injury or is otherwise drastically less productive this year than he has been in recent years. I don't think this is quite as bad for the Penguins as other teams since they should be willing to spend over the cap by burying his contract if necessary. On the positive side of things, Shero doesn't risk Kunitz testing the free-agent market which could drive his price up.

Kunitz's age is a factor here. At 32 it seems likely that his skills will start to decline. Based on that, it may be surprising that he's not taking a salary cut but you have to remember the salary cap. The first season of his current deal, 2008-2009, the salary cap was $56.7 million. It is currently at $64.3M so his cap hit is down from 6.6% of the salary cap to 5.8%. Putting it in 2009 cap-hit dollars would make his salary $3.3 million, so it is a small drop.

Pittsburgh's Cap Situation

The Penguins are a unique team due to having Crosby, Malkin and to some extent Staal down the middle. I'll discuss the player-evaluation side of that later, but there are major salary-cap implications as well. Next offseason looks pretty standard as far as the cap goes, but bombs are about to fall on the Pens' cap situation. Here are the major players hitting unrestricted free agency, their current cap hit and the summer they become free agents.

PlayerCap Hit $MYear
Sidney Crosby8.72013
Jordan Staal42013
Evgeni Malkin8.72014
Kris Letang3.52014
Brooks Orpik3.752014
Chris Kunitz3.752014

Orpik seems like the odd man out there, but the rest of that group figures to get a raise and to be honest it's hard to see Shero being able to keep all of them together. In any case, cap space will be at a premium those seasons and Kunitz's contract runs out the summer after Crosby and Staal would need to be re-signed.

Even-Strength Production

The traditional fans would discuss his leadership and Cup experience helping tremendously in the 2009 Cup run. As important as that may have been, I prefer to look at measurable contributions.

Due especially to Crosby, one needs to take a with-or-without-you (WOWY) approach to analyze the production of wingers for the Penguins. Kunitz is a good example of that; he has spent more than half his time in Pittsburgh on Crosby's wing. Here is a table of the Corsi rate for Crosby, Malkin, Staal and none of those with and without Kunitz, as well as the time in minutes that Kunitz spent with them. I'm excluding time where two of Crosby, Malkin and Staal were on the ice together.

Centerw/ Kunitzw/out Kunitzwith TOI (m)
Crosby10.174.912808.3
Malkin5.093-5.336141.4
Staal16.6655.867302.4
None3.4842.025223.9

As you can see, Kunitz improved every line. Crosby's Corsi rate was nearly twice as high when Kunitz was beside him and in smaller samples Malkin and Staal's production was substantially higher with him. I should point out that Malkin's possession numbers without Crosby were drastically better in his shortened 2010-2011 season than previous years and over half of Kunitz's time with Malkin was last year. Kunitz gets some credit for that, but it seems like Malkin was better as well. The fourth line got marginally better results.

It's pretty clear that Kunitz has been a big boost.

Two Potential Concerns: Injuries and Scoring

In the summer, Pensburgh wrote a nice summary of both Kunitz's injuries and scoring with the Penguins. For a left winger, his points totals have been underwhelming due in part to his injuries. According to this guideline at PPP, an average first-line left winger would put in 27 goals. In the last three seasons, Kunitz put up 23, 13 and 23 goals. Going to points, the average for a first line left wing is 50 and Kunitz put up 48, 32 and 53 the last three years. So he's somewhere between an average first-line winger and an average second-line winger when it comes to scoring. A big reason for this is obviously missing significant time the last two years.

Another factor is that Kunitz's individual points percentage is nothing to write home about. He registered a goal or assist on 69.4% of all 5-on-5 goals scored with him on the ice, 7th highest among forwards on the team. This combined with his Corsi numbers make sense given his role - he is important in driving play, helping to move the puck into the offensive zone and keep it there, but Crosby is typically the man with the puck in the attacking end. I don't think his somewhat low scoring for a first-line winger is an issue given his role.

The Verdict

Overall, I think it's a good deal for both sides. Kunitz has been a very good role player the last 2+ seasons for the Penguins. While he is on the wrong side of 30, it seems reasonable to expect a similar level over the life of the contract. Injury concerns and his contract ending the season after Crosby and Staal are due to sign their extensions keep me from saying it is a great deal for the Pens, but even Shero would have to spend some money on wingers.

Monday, October 3, 2011

Driving Play Season Preview: Teams 6-4, The Second Tier Elites

6. Detroit Red Wings

Key Statistics:

Fenwick- 53.6%
Even Strength Shooting%-8.5%
Even Strength Save%-.922

2010-2011 Summary

Once again, Detroit was near the top of the league in both territorial play and in points, all this despite losing 26 games from Pavel Datsyuk, 13 games from Dan Cleary, 19 games from Brian Rafalski, and 15 games from Brad Stuart.  Detroit got decent enough goaltending, as well as good years from all of their supplemental pieces.  They simply ran into a slightly better team in the playoffs.

Offseason Changes

The only major move made this summer was the retirement of Brian Rafalski and his subsequent replacement with Ian White.  As Triumph and I chronicled, this was a definite upgrade for Detroit.  White is a superior player who comes at less than half the price.  The saved cap space didn’t really come into play in further offseason moves, though it also gives Detroit a cushion if they needed to make an in-season move. 

Key Questions for 2011-2012

Is Detroit deep enough along the blueline?    
  • While Detroit features a formidable top 4, I believe there are legitimate concerns past that point, especially in the event of injury.  Jonathan Ericsson took a big step backward last year, and Jakub Kindl has shown little to give the impression that he wouldn’t be overmatched playing heavy minutes.  Other than that, I think forecasting Detroit’s success is pretty straightforward.  This is largely the same team as years past, and every NHL fan can understand what that means.

5. Pittsburgh Penguins

Key Statistics

Fenwick- 54.3%
Even Strength Shooting%-6.8%
Even Strength Save%-.929

2010-2011 Summary

In a word: injuries.  Pittsburgh’s two best players spent significant time on Injured Reserve, with Evgeni Malkin missing nearly 40 games with various knee injuries and Sidney Crosby missing 41 games after noted headhunter David Steckel viciously ran Crosby in the Winter Classic.*  The Penguins still managed to put together a good season, even finishing first in the league in Fenwick, but the ability to consistently put pucks in the net was glaringly obvious. Thanks to a great season from Marc-Andre Fleury, Pittsburgh was able to remain relevant, finishing with 106 points. 

Offseason Changes

Pittsburgh lost two bottom-6 forwards to division rivals with Mike Rupp’s departure to the Rangers and Max Talbot’s move to Philadelphia. Outside of that, their roster will generally look the same as last year, with the most major addition coming with the signing of veteran winger Steve Sullivan. 

Key Questions for 2011-2012

At what point can we expect Sidney Crosby to return?
  • Crosby has already been ruled out of the season opener, which while not a good sign is still not the end of the world assuming Malkin and Staal remain healthy.  But still, the team needs him in the line-up.  A Crosby-less Penguins team still makes the playoff, but #87 is the difference between an elite team and a team that makes it as a bottom seed before losing in the first round.

Should Evgeni Malkin move to wing?
  • This only happens if Crosby is healthy, but is a move I think should be made (and is a move a few of us on this blog have talked about for a while).  Malkin’s contributions at Even Strength have fallen each of the last few seasons.  He’s never been great at faceoffs, and center depth (again, assuming Crosby’s health) isn’t much of an issue for Pittsburgh, and I believe the lightened responsibility could help bring his game back to where it was in 2008.   

* - Don’t worry, I’m only joking.


4. San Jose Sharks

Key Statistics from 2010-2011

Fenwick- 53.7%
Even Strength Shooting%-7.2%
Even Strength Save%-.942

2010-2011 Summary

The Sharks had a pretty boring year last year (I mean this in a good way), as they won another Pacific Division title and again came within one postseason round of the Stanley Cup Finals.  San Jose’s biggest story last year was the emergence of Logan Couture, who centered what was San Jose’s best line for most of the year, and whose presence ultimately made Devin Setoguchi expendable (more on this later). 

Offseason Changes

Outside of Washington, San Jose had the busiest summer of any of the NHL’s elites.  The offseason bonanza began on Draft Day, with Doug Wilson sending Devin Setoguchi, top prospect Charlie Coyle, and a 2011 1st round pick to the Minnesota Wild for Brent Burns.  This was the first of two blockbusters between the Sharks and Wild, as the two teams swapped All-Star wingers, with the Sharks sending Dany Heatley and receiving Martin Havlat.  The Sharks also signed Michal Handzus, ostensibly to play the role of 3rd line center.

Key Questions for 2011-2012

How will Joe Pavelski do on the wing and whom will he play with?
  • Logan Couture’s rise gave Doug Wilson the flexibility to move a top 6 winger in Devin Setoguchi, primarily because he had another top 6 forward who was then being used on the 3rd line.  I think it’ll be interesting to see what (if any) impact this has on Pavelski’s game.  I also think it’ll be interesting to see what line he plays with, though this will obviously change throughout the year.

Were last year’s troubles on the PK just an aberration or a legitimate cause for concern?
  • Known in previous years for having one of the league’s best kills, San Jose had an uncharacteristically bad year on the PK.  Michal Handzus should help up front, and Colin White and Brent Burns should help on the back end, but it still remains to be seen if that is enough, especially with the departure of Jamal Mayers and Scott Nichol.
The final 3 will be posted tomorrow morning.  

Here is a recap of our rankings to date:

30. Edmonton
29. Colorado
28. Dallas
27. New York Islanders
26. Minnesota
25. Ottawa
24. Toronto
23. Florida
22. Phoenix
21. Winnipeg
20. Anaheim
19. Carolina
18. Calgary
17. St. Louis
16. Nashville
15. New York Rangers
14. Columbus
13. Buffalo
12. Philadelphia
11. Boston
10. Montreal
9. Tampa Bay
8. New Jersey
7. Los Angeles
6. Detroit
5. Pittsburgh*
4. San Jose

* - With Sidney Crosby

Friday, August 19, 2011

On Luck, Skill and Sample Size in Shooting Percentage

The roles of skill and luck in shooting are an important and often misunderstood part of hockey analysis. This is particularly true when analytical and traditional fans get together. A typical discussion might go something like:

A: Steven Stamkos got 91 points with 45 goals at the age of 21. He's definitely getting 100 points next year, and could easily score 50 goals a season as he improves.
B: Yeah, but he was lucky to make 16.5% of his shots. That's not sustainable and his numbers will probably go down next year, even if he does actually improve.
A: So shooting is all luck? You clearly know nothing about hockey and should actually watch some games instead of just sitting at your computer all day coming up with fancy stats that don't mean anything.

Turns out both guys have a point. Stamkos should probably expect his stats to drop next season because, in addition to goal numbers trending downward for the league as a whole, he's probably not burying 16.5% of his shots. On the other hand, I person B probably should watch more hockey, it is a great game.

A lot of the confusion comes from incorrect either/or thinking. Scoring on a high percentage of your shots is a result of both luck and skill. I'm not just putting down the traditional fans here. Those of us in the analytical community, myself included, are prone to bad thinking as well. While most people ignore or underrate the importance of luck in hockey in general and shooting in particular, we tend to go too far the other way, chalking everything up to luck and ignoring the skill aspect.

Shooting for a high percentage is skill based. Two of our favorite writers, JLikens of objectivenhl fame and Gabe Desjardins from BTN and arcticicehockey have written several articles on the subject.

In case their articles are not convincing enough, let's consider two of the best players in the game: Henrik Sedin and Sidney Crosby. While not necessarily known as snipers, these players have all the skills that one might think lead to their team putting a high percentage of shots in the net. Both have elite vision, passing ability, hands, positioning and, in one case, telepathy. We would all expect their teams to have better shooting percentages when they are on the ice than when they are sitting on the bench or worse. The numbers bear this out. Here is a chart with their teams' performances at even strength with both goalies in net from the last four seasons combined. The stats are courtesy of noted Driving Play reader Vic Ferrari's timeonice scripts, which you can find information on how to use here.

TeamGoalsShots On GoalShooting %
Penguins, Crosby on Ice236216010.9%
Penguins, Crosby off Ice41453477.7%
Canucks, Henrik on Ice273262410.4%
Canucks, Henrik off Ice35947097.6%

As you can see, the Pens with Crosby shot 3.2 percentage points higher than they did without him. While some of it may be variance, with the number of shots they took with him on, that's a difference of 69 goals or more than 17 goals per season due to better shooting. The Canucks shot 2.8 points higher with Henrik on the ice, a difference of over 73 goals, more than 18 per season, when you consider how many shots they took with him on. For the statistically minded, these shooting-percentage differences are very very very significant. To give you an idea, it varies field to field but the most common benchmark is for there to be less than a 5% chance of results this extreme, or more so, due to variance alone. That's a 1-in-20 chance. For Crosby, there is a 0.00045% chance, or less than 1 in 222,000. For Hank there is a 0.00235% chance of results that extreme due to randomness alone - less likely than 1 in 42,000. Again, 1 in 20 is the usual mark. The data confirm what anyone would guess from watching a few games - Henrik Sedin and Sidney Crosby help their teams shoot better. (Note: if you are a hater and/or think that it's the likes of Alex Burrows and Pascal Dupuis who are driving these results, feel free to be wrong. The point of this is to provide evidence of shooting skill and clearly someone has it when these two are on the ice.)

Let's now look at the role of luck on shooting percentage. To do this, I will run simulations comparing the results of a typical team that shoots well and one that does poorly. In this article on objectivenhl, which is worthy of being linked again, JLikens finds that the average team shoots at an 8.1% clip 5-on-5, with a standard deviation of 0.48%. Going by this, a team that is good at shooting, let's say 7th or 8th best in the league, would have a true 5-on-5 shooting percentage of something like 8.42%. On the other hand, a team that is bad at shooting, say 7th or 8th worst in the league, would be expected to score on about 7.78% of their shots.

Let's see how things shake out. Below is a chart giving the results of 10,000 simulations for various numbers of shots where team A has a true shooting percentage of 8.42% and team B shoots at 7.78%. The first two columns tell you the given time period and number of shots for each team. The next three columns tell you how often the team good at shooting outshot the bad (column 3), the bad team outshot the good (4) and how often they had an equal shooting percentage (5). The last two columns give what percent of the time someone looking at the data, and not knowing the underlying percentages, would get statistical signficance at the 5% level. Notice that in the last column, the statistical test would reveal that B is significantly better at shooting than A despite their shooting skill actually being over half a percentage point worse.

Time periodNumber of ShotsA scores moreB scores moreGoals scored equalA > B SignificantB > A significant
One Period831.9%28.7%39.4%1.3%1.1%
One Game2442.6%36%21.4%6%4.5%
1/4 Season50062.3%33.2%4.5%10.5%2.2%
1/2 Season1,00068.6%28.5%2.8%13.4%1.4%
1 Season2,00076.4%21.7%1.9%17.9%0.8%
2 Seasons4,00085%14%1%27.8%0.2%
3 Seasons6,00090.1%9.3%0.6%36.1%0.1%
4 Seasons8,00093.6%6%0.4%43.7%0.1%
5 Seasons10,00095.6%4.1%0.3%50.3%0%

You probably didn't find the results surprising for that first row, representing a period of play. The most common outcome, happening about 40% of the time, is that the two teams remain tied, most often at 0. The team that shoots better due to getting higher-quality shots, hitting the corners better and so on is only slightly more likely to be the one that is ahead if you know that one of them is. Less than 32% of the time will the better team find themselves ahead after a period in which both get the league average 8 shots, whereas they'll be behind almost 29% of the time.

Lower on the chart it gets more troubling, especially for us bloggers. The most common sample point for analysis is half a season. Generally the best way to study the persistence of something is to split the season in half, typically first half vs second half or even-and-odd numbered games, and compare the two samples. This works well because teams should be the same or very similar. If you study something over multiple seasons you aren't getting the same teams every year due to player and coaching changes. In half a season, the team near the top in shooting skill has only about a 2 in 3 chance of outscoring the team near the bottom with the same number of shots. There is also little chance, roughly 13%, of finding that the better team is significantly better at shooting if you were looking at the data. Even over a whole season of shooting data, there is a 1 in 4 chance that the worse team will get better results. It isn't until we get several years worth of shooting results that it tilts heavily in favor of the better shooting team and that's not realistic because teams change so much each offseason and the simulations assumed the same percentage each season.

As you can see, luck plays a huge role for all reasonable sample sizes. This is the fundamental reason why shooting stats are better than goals. Luck is less of a factor for number of shots taken than number of shots made, so they are more reliable indicators of skill over samples of a season or less. If over a season there is a 1 in 4 chance that a good-shooting team is outshot by a bad-shooting team then it's tough to say that a team's results are due to skill and not just random luck.

In a future installment I will look at how persistence is affected by sample size.