Friday, 28 June 2013

Slicing and Dicing: Re-Examining Data on Draft Eligible D-Men

I love getting feedback and hearing from other people when I write stuff, even if it's simply to tell me that I'm an idiot for reasons X, Y and Z. It gives me ideas on how to examine my arguments in different ways and see if my initial conclusions were either flawed or could be refined. A couple of people made some good queries this morning that I feel are worth looking at, so that's what I'll take this time to do.

First off, @garik16 raises a valid point. Assists may be influenced by teammates in both positive and negative ways, so perhaps looking at goals per game played will yield a clearer picture of offensive ability than points per game does, and subsequently forecast NHL success more accurately:
As it turns out, the scatterplots for G/GP vs. NHL% of GP and  Pts/GP vs. NHL% of GP behave in very similar manners. Both have large clusters of non-scoring early-round busts at the bottom left hand corner, while the rest of the plot is pretty random. In both cases, there isn't enough of a linear relationship present to conclude a direct correlation between offensive output in the CHL and NHL success, however, as I said before, there is enough evidence to conclude that guys who don't score in the CHL don't become NHL players. Here's the plot:


It looks like there could be a linear relationship here if the picture wasn't clouded by so much noise at the bottom and so many outliers to the right. I'm not about to eliminate half of my data though, so we're left with this mess.

What I find interesting is that when you move to 0.25 CHL draft year G/GP, most of the guys end up flaming out before making the NHL. In fact, here are the top-10 CHL defensemen in this sample, sorted by G/GP:


Personally, I think this list is hilarious. The only "regular" NHLers here are St. Louis Blues spare part Kris Russell, journeyman Steve Eminger, and one of the all-time busts in Cam Barker. The rest of these guys can't even crack an NHL roster full-time. So how did they perform so well in their draft years? The most probable explanation is something that we see in the NHL all the time: individual shooting percentage is volatile in small sample sizes, leading to inflated goal totals over a single season.

It's circumstances like this where possession numbers as well as deployment patterns and shooting percentages would be very informative. After all, we're looking at such a small sample in "defenseman goals in a single short season." Possession metrics effectively expand the sample size allowing us to paint a more meaningful picture of what's happening on the ice over a shorter time period. Hell, even looking at just individual shots on goal should expand the amount of data available by 2000% (assuming a CHL d-man shoots at something like 5% on average). Unfortunately, this data wasn't available to me when I was data mining over on hockeydb.com so it'll have to wait for another day, if it even exists at all.

So to finally answer what @garik16 was wondering, looking at G/GP doesn't tell us much, at least not about the data I have. This is probably because goals provide such a small sample of data that they're just too volatile to conclude anything more than what we already knew merely by looking at Pts/GP. While assists may introduce "quality of teammates" noise, eliminating them introduces a lot of randomness noise.

---

The other point that was mentioned by a couple of people was that guys drafted in the first round tend to be offensive guys, with the implication that guys drafted in the 2nd and 3rd rounds are regarded as riskier anyways:

First off, I'd hesitate to call it a "0.6 Pts/GP rule" since I think putting a set-in-stone number on it tends to make it look like I believe what I'm presenting is gospel. It isn't. I'm merely trying to present evidence to make the point that defensive ability is probably overvalued in CHL defensemen, and that GMs probably shouldn't spend early round picks on guys who exhibit no offensive ability.

Anyways, to test to see if my theory holds up when looking at the data round by round, I divided the total sample of players up in to three batches, based on Derek Zona's "Impact Player Percentage." This is essentially a percentage measure of how many players from a particular grouping in the draft turn out to be impact NHL players. Based on Zona's work, a top-25 pick turns into an "impact player" roughly 39% of the time, a player drafted anywhere from 26th to 50th becomes an impact player 15% of the time, and someone taken between picks 51 and 100 becomes an impact player about 7% of the time.

Of course, my definition of a "successful pick" is different than what is defined as an "impact player." Since my definition doesn't stipulate how frequently a player must score at the NHL level, my definition should yield more "successes" than there are impact players. Therefore, the success rate of NHL teams drafting a defenseman in each batch of picks should, in theory, exceed the impact player percentage of that same batch. In other words, since 39% of top-25 players become impact players, significantly more than 39% should be what I call successful picks.

I then divided each batch into two sub-groups of "scorers" and "non-scorers." If defensive defensemen are just as risky or less risky than offensive defensemen, the success rate of each sub-group should be similar to one another, and above the impact player percentage for that range of picks. Here's what the batch-by-batch relationship between NHL % of GP and CHL Pts/GP looked like:




What I notice right away is that a higher proportion of scoring defensemen are drafted in the first 25 picks compared to the 26th - 50th picks and the 51st - 100th picks. However, within these batches, does my initial conclusion that primarily defensive guys are still more risky hold true? I assembled the information into a table to check:


As you can see, scoring CHL defensemen turned into successful draft picks at a higher rate than defensive CHL defensemen in every single batch. Even though the success rate of non-scoring CHL d-men exceeded the batch impact player percentage (labelled as "impact rate") in both the first and second rounds, the difference is so small that I'd feel confident in saying that a well lower than average amount of these picks go on to become impact NHL players. An NHL team would be far better off using the pick to take a scoring defenseman or a forward.

So, after analyzing the data in yet another way, I'm left with the same conclusion: non-scoring CHL defensemen carry a disproportionate amount of risk and fail to become NHL players more often than not. I will say that I have softened my stance on Samuel Morin and Nikita Zadorov based on the information I looked at today, however I still believe that they're both unlikely to become NHL regulars and shouldn't be drafted if guys like Pulock, Morrissey or Theodore are still on the board. Even "risky" Jordan Subban is as likely to become an NHL regular as "safe" Zadorov is. Also, guys like USNT product Steve Santini should probably be bypassed entirely in the early rounds of the draft because their offence just isn't there. I hope I've done enough to demonstrate that defensive ability in the CHL is overvalued and that offense and puck skills have historically carried far less risk among draft-eligible defensemen.
Posted by at 2 comments:

Thursday, 27 June 2013

Defending The Defenseman Post

James Mirtle and I had a good Twitter discussion about the defenseman post, and I think his criticisms raised some really good issues and points that I probably need to clarify. I'll go a couple of them in depth because they're questions I can see being raised by others too.

1) "What about player X? He doesn't fit this pattern."
This is true that Chara wasn't a big junior scorer, but then again, how many 6'9'' players have ever played in the NHL? Bruce Arthur also makes the point that even among big men, Chara is somewhat of an anomaly with his immense on-ice ability. But even the data presented in my last post shows that guys who aren't big scorers in junior can go on to NHL success. To this point, I'd simply say that there are exceptions to every rule, and broad-brush analysis isn't going to be applicable to every individual case.

With this being said, there are still far too many examples of guys who were drafted for size or defensive ability that never turned into NHL regulars because they couldn't score. Branislav Mezei, Boris Valabik, Matthew Spiller, Ryan Parent, Matt Pelech, Libor Usturnl, Andy Rogers and Logan Stephenson are all players that were taken early in the draft because of their size or defensive ability, only to find themselves unable to make it as an NHL regular. The list goes on and on and on, too.

The point that I think should have been made more clearly in the last post is similar to the one Tyler Dellow made here: defensive defensemen at the NHL level far more often than not exhibit puck skill at the CHL level. Guys who are known as prototypical shutdown NHL D-men, including Barrett Jackman, Rostislav Klesla, Nick Schultz, Brent Seabrook, Dan Hamhuis, Tim Gleason and Karl Alzner, all were significant offensive contributors to their CHL teams in their draft years.

Of course, this begs the obvious question:
Based on the window of drafts I studied (1999 to 2008), and my cutoff point for an NHL regular (played in 40% or more of available NHL games), these are the guys who scored less than 0.5 Pts/GP in their draft year and have still become NHLers:


At first glance, that's an impressive list of names. However, you'll have to remember that this list is only 12 guys out of a sample of 105 that put up similar offensive numbers in their draft season, so these guys are anomalies. The other important fact to consider is that, with the exception of Fistric (probably the least talented player of this sample) and Schenn (who was in the NHL), every single player on this list became a significant offensive contributor their very next CHL season, as they all eclipsed 0.5 Pts/GP. Once again, guys who turn into NHL players, even guys we regard as pylons like Jeff Schultz, tend to be scorers in junior hockey.

2) "Offensive numbers don't do a good job of quantifying defense."

 I agree with James' point here. At the same time, I'm not evaluating defense on the basis of offense. As I touched on in the section above, defensive value of CHL defensemen doesn't seem to translate to the NHL if the player in question isn't a two-way force in his junior career. Almost all of the players that became good NHL defensive defensemen drafted in the first three rounds of the draft between 1999 and 2008 had a high scoring rate in junior, and the vast majority of early round busts in that same time frame were guys who simply didn't put up points in the CHL, as was shown by the data presented in the previous post.

This means that of the draft-eligible defensemen from the CHL, some are riskier picks than others. Here's the table of the CHL guys ranked in the consensus top-90 again:


History has shown us that guys like Zadorov and Morin are risky picks. If I were an NHL GM, I wouldn't draft either of these players unless I was convinced that they did possess enough offensive talent to become a big scorer in the CHL in their draft +1 and +2 seasons. James indicates that some scouts believe this is true of Zadorov, and I hinted in my last post that I think Madison Bowey could be a similar case from my limited viewings of the Kelowna Rockets.

I didn't think that "points are not the be-all-end-all" was something that I needed to explicitly state, and obviously there are a ton of other factors that go in to predicting whether a draft pick will be successful or not. However, as a broad brush analysis, CHL point totals still paint a pretty clear picture that guys with no offensive ability in major junior rarely turn into NHL players.

I hope this clarifies some of the statements I made previously, but I still think the rule of thumb conclusion that I came to in the last post is valid: defense at the junior level - be it size, physical play, shot blocking or something else - is overvalued, resulting in a disproportionate number of early round busts. As this is the case, in my mind at least, Nikita Zadorov probably shouldn't be more highly regarded than Ryan Pulock or Josh Morrissey, or maybe not even more highly than Shea Theodore or Jordan Subban just based on the historical examples of what successful NHL defensemen tend to do when they're in junior.
Posted by at No comments:

Wednesday, 26 June 2013

Defense, Defensemen, and the Draft

Pittsburgh's Scott Harrington. Future draft bust?

One of the things that drives me off-the-wall crazy about Hockey Canada at the junior level is the fetishization of stuff as nebulous as "heart" and "grit" and "toughness." Consequently, we get guys on our international junior teams who, when they appear to exhibit some of these intangible qualities, are lauded for their on-ice defensive abilities. Take, for example, Scott Harrington. A Penguins 2nd round pick in 2011, he was named the captain of the OHL champion London Knights this past season (leadership!), was a finalist for OHL defenseman of the year (defense!), and was guaranteed a spot on Canada's World Junior Championship team's blueline because he was there before because he blocked shots (heart!). Corey Pronman lists him as one of Pittsburgh's top-10 prospects, saying that his upside is a 3rd or 4th NHL defenseman due to being a "high-end thinker" with stellar defensive ability.

And yet he'll more than likely be out of NHL hockey by the time he's 25, doomed to a career bouncing around the minor leagues and Europe, mostly because he's not a very good hockey player, relatively speaking. It's a good thing I'm about to spend somewhere in the neighborhood of 1500 words backing up this claim, or else you might think I'm crazy.

---

Since the draft is just around the corner, I decided to take a look at all the CHL defensemen drafted in the first three rounds between 1999 and 2008 to see if there was any link between offensive production at the junior level and NHL success. Tyler Dellow has danced around this topic in the past, pointing out that depth roster players are mostly high draft picks that don't achieve star offensive status in the NHL, and that most defensive defensemen of consequence establish themselves as NHL regulars by their early twenties, but I've yet to see someone go through each pick and look at which ones were successful and which weren't, even though I'm sure such a study is out there.

My hypothesis was that to be a regular NHL defenseman, you probably had to be an outstanding player in the CHL at both ends of the ice. Consequently, guys drafted for their "defensive abilities" but couldn't score would make up the vast majority of early-round draft busts, at least when it came to defenders. I decided to use a 10-year window of drafts, with the most recent one I looked at being 2008. This gives the most recent batch of players I looked at five years to get acclimated to the NHL and start to stake a claim to a roster spot that they'll ideally hold down for years to come. I also stuck to the CHL for a couple of reasons: 1) it's the biggest feeder league of players to the NHL, and 2) it's probably the most familiar major junior league to me as well as any other Canadians (and certain Americans too) in terms of styles of play and levels of competition.

I evaluated players on the percent of NHL games played, relative to the total games available to play over that time. For example, since Dan Hamhuis was drafted in 2001, he was eligible to play in a total of 868 NHL games. He has played in 676 games over this span, meaning that he has appeared in 77.9% of NHL games. For the purposes of this study, I defined an "NHL regular" as someone who has appeared in 40% or more of the games they were eligible to play in. I then compared this percentage to their draft-year points-per-game and made a scatterplot. It's pretty rudimentary stuff, but the results are still pretty telling:


Note the massive cluster of points on the bottom left hand line of the plot, and how it magically disperses once it reaches about 0.55 Pts/GP. This tells me that while scoring in junior doesn't guarantee NHL success, not scoring in junior more often than not predicts NHL failure. To illustrate this point better, I divided the plot into quadrants (divisions at 40% NHL GP and 0.6 draft year Pts/GP) and made note of how many players fall into each category:


Based on historical data, a CHL defenseman taken early in the draft with fewer than 0.6 Pts/GP in his draft year, like Scott Harrington or Dylan McIlrath or Colten Teubert, only has about a 1 in 10 chance of even making the NHL as a full-time player. Going back to Harrington, only 3 players in the last 15 years have scored at a lower rate in their draft years and established themselves as NHL regulars: Mark Fistric, Tyler Myers, and Shea Weber. However, Fistric was never a big scorer and finds himself dangerously close to falling out of "NHL regular" status, while Weber and Myers grew into elite 19-year old scorers in their draft +2 seasons. Weber had 0.75 Pts/GP with Kelowna, and Myers put up an impressive 48 points in the NHL. Harrington still finds himself under 0.40 Pts/GP in his draft +2 season, which means he's tracking to be just like the other 91 guys who haven't ever made the show full-time.

So what does this mean for the draft on Sunday? Well, according to the NHLNumbers.com consensus top-100 players, there are 15 CHL defensemen ranked in the first 3 rounds. They are as follows:


Just based on the stuff that was outlined above, you can say with a fair degree of certainty that Zadorov, Morin, Heatherington, Diaby and Kanzig all will not be long-term impact NHL players (coincidentally, all of these guys are 6'5 or taller, with the exception of 6'3 Dillon Heatherington) unless someone gets really, really lucky. It just goes to show the love affair that scouts have with nice bodies, as Dan Dorazio will tell you:



Other players like Mueller and Bowey should be regarded as very risky picks, too. They are probably much more skilled than the five big guys listed above, and I'd be anxious to see how they do in their draft +1 and draft +2 years. I'm no scout, but Bowey's meager 30 points is really surprising to me considering how great of a skater he is and how well I've seen him play with the puck.

Also, Corey Pronman calls Jordan Subban "risky" because of his small frame and defensive question marks, when he's probably a far, far less risky pick than either Zadorov of Morin. A coach can tell guys where to stand in the defensive zone, but a coach can't tell a guy to be talented. As the numbers have shown, the youngest Subban probably has a 50/50 shot at the NHL, whereas the odds are stacked against the 9th ranked Zadorov about 10/90.

The overriding lesson here, however, is don't draft a defensive defenseman early since it rarely, if ever, works in your favour. The few that do work out almost always put up big offensive numbers in junior before turning pro anyways, as I'll point out in just below. Of course, this philosophy probably extends out beyond the draft eligible CHL crop of talent, too. If I was an NHL GM, guys like 37th ranked Steve Santini out of the USNT (0G, 13A in 62GP) would be completely out of the question as well. I'm no expert, but the numbers seem to agree that guys who actively contribute to winning hockey games by scoring eventually turn out to be good at hockey. Really, this should all just be common sense.

---

As an aside, I always find it fascinating to look at the guys who are the anomalies. Here, they are the guys in the top left and lower right quadrants. How did the low-scoring guys make it? How did the high-scoring guys fail? Here are some of the explanations for why the outliers are outliers:

How they made it:
- Kris Letang (62nd overall, 2005) and Marc-Edouard Vlasic (35th overall, 2005) both had less than 0.5 Pts/GP in their draft years, but surged to over a point per game the very next season. Despite falling in the "unlikely to make it" category, they still both had a history of putting up big offensive numbers in junior.
- Marc Staal (12th overall, 2005), Dion Phaneuf (9th overall, 2003) and Travis Hamonic (53rd overall, 2008) all also had less than 0.5 Pts/GP in their draft years, but all reached above 0.6 Pts/GP by the time their draft +2 seasons had ended. Phaneuf and Hamonic were better than a point per game in their final years of junior.
- Braydon Coburn (8th overall, 2003) definitely had a down year in his draft season. He only scored 19 points in 53 games in 02-03, but had more than 0.5 Pts/GP every other year of his WHL career.

How they missed:
- Andrew Campbell (74th overall, 2008) was drafted as an overage '85 birthday in the '87 draft class after scoring 35 points in 68 games. In his first draft eligible season, he had 4 points. Danny Syvret (81st overall, 2005) is a similar case.
- Jesse Lane (91st overall, 2002) had a very promising 0.84 Pts/GP in his draft year, however decided to quit hockey to pursue his studies once Carolina declined to offer him an entry level contract after a strong junior career.
- Ivan Vishnevskiy (27th overall, 2006) is the only player in the bottom right group to leave for the KHL. He most recently played in North America for Chicago's AHL affiliate.
- Some players were drafted high after an obvious outlier season. Examples include Alex Plante (15th overall, 2007), Dustin Kohn (46th overall, 2005), Martin Vagner (26th overall, 2002) and Josh Godfrey (34th overall, 2007).
- Other players in this bottom right group may just have yet to establish themselves as full-time NHL players. Guys who are close to full-time duty include Thomas Hickey (4th overall, 2007) and Bob Sanguinetti (21st overall, 2006).
Posted by at No comments:

Tuesday, 4 June 2013

Why Are We So Damn Ignorant?

For some reason, rather than continually explore new avenues and attempt to enhance our understanding of how hockey actually works, we (I'm using "we" fairly broadly here) seem to instead bury our heads in the sand, dig our heels in, and resist new ideas and concepts. This is especially prevalent if these new ideas are in the form of acronyms or contain decimals. Tonight, my absolute favourite TV hockey personality Steve Kouleas left Twitter with a gem of an anti-thinking tweet, and wouldn't you know it, the analyblogotwittosphere or whatever we're calling it jumped all over him. I'm not going to rip Kouleas here because I find him insufferable and it'll turn into a rant, but I'll address some stuff that really has been bothering me; mainly just how to meld stats with more "traditional" analysis done by the talking heads in a way that makes the staple intermission or pregame or postgame panel much more informative or insightful.

But first, a rundown of what happened, just to prove I'm not setting up a strawman here. I don't know what prompted it, but ol' Stevie just felt it necessary to throw this out there:

That's not even grammar'd correctly, and the excessive use of ellipses basically undermines any point he may have been trying to make since they show he has the punctuation skills of a second grader, but that's irrelevant. The main point is that this is a major host on perhaps the world's most influential television network when it comes to meaningful hockey analysis is completely dismissing the underlying school of thinking that seems to be slowly welling up beneath the traditional mainstream narratives. You would think that, as a network dedicated to feeding hockey programming en masse to the insatiable Canadian populous, TSN would also strive to deliver the most insightful programming too. For the most part, I think they're the best of the three major Canadian networks, with guys like McKenzie, Dreger, LeBrun, and even Ferraro and Ward at their disposal.

TH2N seems wildly divergent from this perception however. It's like something CBC's panel would do sans Friedman. "LOOK HOCKEY TALK LOUD NOW," or something like that. Aside from the banal shouting that goes on between Kouleas and Button (whom I think is horribly miscast), there's also the fact that berating alternative viewpoints seems to be the norm from TH2N regulars, as shown by STATS GUY tonight and Steve Simmons a while ago:

Other than the obvious "I claim to understand your ideas completely but really I have no idea" stuff that's going on here, I don't think that taking the stance of "it will never work!" is either productive or even smart. As Broad Street Hockey's Eric Tulsky pointed out earlier tonight, a lot of smart people have spent a lot of time looking at this stuff. Dismissing it outright works on the same logic as denying climate change or suggesting that smoking doesn't cause cancer. Unless you can defend your argument that Corsi is "ridiculous nonsense" with actual strong evidence, your opinion is invalid, no matter how how large the pulpit you preach from (and as we all know, a one-game sample that lacks any sort of context is flimsy evidence at best).

---

This all brings me to my main gripe with how hockey is being analyzed right now: incorporating stats, educating your viewership, and making your product better would be incredibly easy and I don't understand why it's not being done. Take Hockey Night in Canada for example. On one hand, you have Elliotte Friedman getting free reign to use timeonice.com in an intermission bit, and then on the other Glenn Healy claims that Pavel Datsyuk isn't that talented. Fortunately, you only need one guy to know what he's talking about to present a segment in a way that makes everyone come across as intelligent. Imagine an intermission segment on HNiC as follows:

MacLean: "The Boston Bruins are up 2-0 on the Penguins. Who could have seen this coming, Elliotte?"

Friedman: "Well Ron, according to some of the most reliable measures we have on predicting future success, the Bruins were by far and away the better team than Pittsburgh through the regular season. We all know that Detroit built a decade of success on the back of puck possession, and the best measures of puck possession we have at our disposal are a couple of stats called Corsi and Fenwick. *brief explanation of both stats followed by a chart showing the massive difference between BOS and PIT in these measures.* So while this fast 2-0 lead for the Bruins may be surprising to some, it really shouldn't be."

MacLean: "So PJ, what are the Bruins doing in these playoffs to keep up this great puck possession play?"

Stock: "It's all about the 50-50 puck battles. Here you got a guy like Bergeron who's a great player and look at him work against Crosby here *hilight reel of Bergeron and other Bruins fighting for pucks along the boards.* You win with guys like Bergeron. They turn pucks over and give it to your team and help you keep the puck for more of the game."

MacLean: "But coaching has an important role too, Kevin?"

Weekes: "Absolutely. You look at how Boston is structured in their defensive end, and they keep pucks to the outside and cause turnovers. Pittsburgh on the other hand is really loose. Look at how poor their coverage is on this Krejci goal! They're chasing the Bruins all over the ice, and never in a good position to get the puck back if they turn it over. As a result, Boston has the puck more and they're winning."

A segment like that introduces and explains a statistical concept, and then outlines the factors and events in a hockey game that go into that stat. Not only does it simply run through numbers, but it marries the newer wave of analytics with the traditional narrative in a way that should be more easily understandable to viewers. Stats aren't intrinsically divorced from the old-school way of looking at hockey, but mainstream analysts really have yet to make the connection between what we see going on, and what we measure going on. It's not a hard connection to make, but I really hope it happens sooner rather than later. Hockey needs more Friedmans and less Kouleases.

---

One last thing: my favourite part of this whole thing was when Kouleas challenged Twitter to "go to a coach or GM and ask them a question on it" and both a coach and a GM immediately responded telling him that he was full of shit. I really hope the Soo Greyhounds win a Memorial Cup soon since it would be nice to see an organization that embraces analytics so openly get rewarded for it.
Posted by at No comments:

Wednesday, 1 May 2013

Know Your Enemy: San Jose Sharks

With the playoffs now upon us and mere hours until the puck drops in Vancouver's 2013 postseason, now is as good a time as any to really get to know that Canucks' first round opponent, the veteran-laden San Jose Sharks. I'll focus on the forwards here, mainly because I think this is where the key matchups are, and where the outcome of the series will be determined. Also, CanucksArmy has an excellent breakdown of the defense, goaltending and special teams of the two squads, so go read that too, if you haven't already. This post will cover how Todd McLellan deploys his team, how they perform, and ultimately how we can expect the Canucks to counter. So, let's get to it.

 Deployments
The Sharks boast a very deep forwards corps, especially with the re-emergence of Brent Burns as a Byfuglien-like power forward flanking Joe Thornton on the Sharks' top line. Based on Thomas Drance's series preview at CanucksArmy, here's what we can expect San Jose's lines to look like and how they will be deployed:

Galiardi - Thornton - Burns
Havlat - Couture - Marleau
Torres - Pavelski - Wingles
Desjardins - Gomez - Burish

Player usage chart courtesy of somekindofninja.com
Unlike we've seen from the Canucks, it does not appear that Todd McLellan likes to spot offensive of defensive zone starts to any of his players, Adam Burish notwithstanding (Torres spent most of his season in Phoenix, so I'm not sure how much of his 58.5% OZone start rate is due to Dave Tippett). As such, we can expect McLellan to aggressively try and line-match with Vigneault. The second line of Couture, Marleau and Havlat will probably be tasked with handling the Sedins, while McLellan will want the Pavelski line against Kesler and have Thornton's group up against Raymond, Roy and Hansen.

Alain Vigneault has been more than comfortable playing power-on-power most of this season, as the Sedins and Burrows lead the all Canucks forwards in Corsi Rel QoC. As such, he probably will not run from the Couture matchup if he perceives that to be San Jose's most dangerous line. If not, he'll run the Sedins out against Joe Thornton. Meanwhile, splitting up two of their better defensive wingers in Higgins and Hansen gives the Canucks two forward pairs (Higgins-Kesler, and Roy-Hansen) that they can use in a similar manner while matching up against the Pavelski line and whichever line the Sedins aren't playing against.

Performance
Based on possession metrics, it's quite clear just how these two teams differ in their construction. While the Canucks have largely been a one-line team for most of the year, the Sharks boast enviable depth up front, as shown by the following two graphs:


I'm not too worried about San Jose's comparatively overpowering 4th line, but the difference between the Higgins-Kesler-Kassian unit and the Havlat-Couture-Marleau line is very concerning. Fortunately for Vancouver, Kesler has proven to be a consistently strong possession player as he posted Corsi per 60 minute rates of +11.77, +17.73, and +13.24 in the three seasons before an injury-diluted -0.27 in 2013. If he can return to that form, his group and the dominant Sedin line should be enough to sink the Sharks. If not, Logan Couture and co. could be the difference in the series.

Another thing to look out for is that after a ridiculously hot start, Patrick Marleau's luck seems to have swung in the other direction, as he finished the season with a 6.81% on ice shooting percentage. In the ebb and flow of an 82-game season, he'd be due for a hot streak. The Canucks hope that it doesn't come in the next 4-7 game stretch.

Oh, and the Sedins are still good. Really good.

Verdict
In a lot of ways, who wins the forward matchup depends on if Ryan Kesler can outplay Logan Couture. Even if the Sedins can win whichever matchup they're tasked with, the Canucks can't afford to give it all back with poor middle-6 play. If Kesler can't step up his game, the Sharks will simply overpower Vancouver's bottom 3 lines, and probably win the series.
Posted by at No comments:

Sunday, 31 March 2013

They Are(n't) Who We Thought They Were

The Canucks lost 4-0 last night to the god awful up-and-coming Edmonton Oilers, and the final score probably flattered Vancouver. This game was really over in the first five minutes when Cory Schneider regressed in a hurry, letting in two goals on the first two shots he saw. Luongo wasn't much better in relief, letting in two more on his first three shots before he settled down and made some miraculous saves that kept the score from looking really absurd. But if you want game reviews, you'll go to Canucks Army or Pass it to Bulis or something. What I want to talk about here is why this Canucks team is so painfully average.

I preface this post by pointing out that the Canucks are currently 4th in the Western Conference, and a top-10 team in the entire NHL, despite some of their perceived struggles and relentless complaining of the Vancouver market. They just rattled off six consecutive wins, and are looking like they'll make the playoffs once again. They still can be good. Ho-hum.

But they're not without their warts, as pointed out by the TEAM 1040's Jeff Paterson:
I don't really believe in excluding games from the sample, because that kind of data manipulation can be used to tell whatever story you want, but since the Nashville game is quite clearly an outlier, it's fair in this case and his point is valid - the team can't score. After last night, they sat in the dead centre of the league in even-strength goals-for per game at 15th overall, rubbing elbows with the Capitals and Wild. They're on pace for 148 even strength goals this season, which is down 12 goals from last year and 17 from 2010-2011. So, where did all the offense go? Well, let's just look at the lineup the Canucks iced yesterday:

D. Sedin - H. Sedin - A. Burrows
M. Raymond - J. Schroeder - J. Hansen
C. Higgins - A. Ebbett - S. Pinizzotto
T. Sestito - M. Lapierre - A. Gordon

D. Hamhuis - J. Garrison
A. Edler - K. Bieksa
A. Alberts - C. Tanev

The Sedins are the Sedins and we all know what they bring, even though their scoring peaks are behind them. I like Raymond and Hansen as top-6 forwards and even more as bottom-6 forwards, but Jordan Schroeder is a career 0.57 points/game player at the AHL level. Given Gabe Desjardins NHLE scoring numbers and Schroeder's production this year with the Wolves, you could reasonably expect 0.3 points/game at the NHL level, or 9 points in 30 games. Amazingly (well, not really) Schroeder has exactly 9 points in 30 games with Vancouver.

So where does that put the Canucks current #2 centre relative to the rest of the NHL? If the top-30 centres in NHL scoring are considered "1st liners," the next 30 as "2nd liners" and so on, Jordan Schroeder is a) producing at his expected level, and b) producing at an average 4th line level. As both Andrew Ebbett and Max Lapierre aren't exactly more attractive options, that leaves Vancouver with three fourth line centres. This isn't exactly conducive to firewagon, high-scoring hockey.

Unfortunately, the outlook on the wings isn't rosy either, especially in the bottom-6. Three of the four wingers on lines 3 and 4 aren't NHL players. Tom Sestito, Andrew Gordon and Steve Pinizzotto have combined for 19 seasons of professional hockey experience, but just 108 games in the NHL. While I think they've been adequate for the most part (Sestito and Gordon's Corsi's aren't awful, considering an OZone start% around 40%), great teams like the Canucks strive to be don't get to be great with half the roster just treading water.

Even though the expectations in this market are still for the Canucks to perform like an elite Stanley Cup contender, the simple fact of the matter is that the holes left in the roster by the injuries to Ryan Kesler, David Booth, Zack Kassian (who was demoted this morning) and Manny Malhotra prevent this team from being anything other than average. Other than the Malhotra situation (if they knew he couldn't play, why was he not replaced?), this is no fault of Mike Gillis or even of Alain Vigneault. You can plan for your two best play-driving forwards to be out for the beginning of the season, but you can't predict that both of them will go down with fluky injuries almost immediately upon returning to the lineup. The bottom line is that the Canucks are what they are, and what they are is an injury riddled team with three fourth lines.

---

Something I don't think gets mentioned quite enough outside of the more analytic circles of the Canucks blogosphere is how massive the Manny Malhotra hole is in the Canucks lineup. Since team management took Adam Smith's economic theory of division of labour to heart, every role player became of elevated importance. Suddenly, Manny Malhotra went from a guy who was good at faceoffs to a key enabler of the offense, as he allowed the Sedins to become elite 80-foot players rather than just very good 200-foot players. The Canucks effectively divided the ice up into three zones and built their team to win each individual one through situational player deployments rather than the traditional chess match of line-matching.

Not only did this get the Sedins more offensive zone time (possibly leading to a boost in true mean PDO for Vancouver like I theorized here), but Malhotra's faceoff prowess probably prevented quite a number of shots against. Some analysis done by Gabe Desjardins at Arctic Ice Hockey found that shot rates spike immediately after an offensive zone faceoff win, as shown in the below graph:

Constructed by Gabe Desjardins. Originally posted here.
Over a longer period of time shot rates converge regardless of winning or losing a faceoff, however the difference in the immediate aftermath of a faceoff is quite significant. Basically, if you have an average faceoff taker starting in your zone (like Henrik Sedin or Max Lapierre), you can expect to see the opposing team realize the dark blue line 50% of the time, and the dark green line the other 50% of the time. With Malhotra on the ice, the split becomes 40% to 60% in your favour. 

I'm not sure how large a reduction in total shots against this would lead to, but Desjardins theorized that every 245 extra faceoff wins at even strength was equivalent to two points in the standings. In the two years prior to this one, Malhotra won 70 and 118 even strength faceoffs more than what a 50% faceoff taker would be expected to win. While Malhotra's faceoff ability alone wasn't worth a win in the standings, it doesn't look insignificant either.

The opposite side of this coin is that the 2nd and 3rd line centremen currently playing on the Canucks roster, Andrew Ebbett and Jordan Schroeder, are both closer to 40% guys, albeit in a small sample. Had these two been tasked with Malhotra's faceoff duties, they would have won 135 and 208 fewer faceoffs than Malhotra did in the two seasons prior to this one, and a further 142 and 180 fewer than regular 2nd line stalwart Ryan Kesler. It's not enough to make a significant impact on the team's overall record (we are talking about faceoff ability alone here, not the other things that Kesler and Malhotra do/did do better that the call-ups), but it's one of the many little advantages the Canucks management and coaches like to have when "designing success."

---

The last point I'll make is how injuries have impacted the Sedins at even strength. Although they haven't been explicitly affected, they don't operate within a bubble. The state of the roster as a whole will impact how they are used and which positions they play in, and right now, the injuries to the bottom end of the roster are necessitating more defensive zone starts for the Sedins and more challenging competition.

Last year, Daniel and Henrik both started nearly 80% of their shifts in the offensive zone. So far this season, that ratio has dropped by close to 15 percentage points to 66.6% and 64.4% respectively. To their credit, their possession numbers haven't dipped at all, but along with Alex Burrows, they're seeing the toughest competition out of all Canucks forwards. The change in their deployment relative to the rest of the team is illustrated in these player usage charts. Since the charts are not on the same scale, I've added a green bubble to where I estimate the twins would be this year on last year's chart:

Player Usage Charts from Greg Sinclair's Player Usage app at somekindofninja.com.
Those plush assignments AV was handing the twins? Yeah, they're not happening as much this season. This increase in QoC and decrease in OZone start% is more than likely due to Vigneault adjusting to a weaker lineup than it is any tangible change to the way the organization wants to use the Sedins. Andrew Ebbett's inability to be an average NHL faceoff guy means that the Canucks need a left-handed centre to take defensive zone draws on the left side of the ice, so by default that job falls to Henrik Sedin. Consequently, OZone start% falls.

The QoC increase is slightly more difficult to explain, but I'd guess that it's because AV really wants to shelter the AHL guys. Pinizzotto, Sestito and Gordon in particular have been playing against some of the opposition's weakest players, whereas Jordan Schroeder is seeing a lot of offensive zone starts against soft competition too. The bottom-9 of last year that ate tough assignments for the Canucks is pretty much in shambles, leaving the heavy lifting to essentially one forward line (and the goaltenders). As a result, the Sedins are seeing more power-on-power matchups this season than they have at any point in the last few years, yet they're still coming out ahead in possession. While their powerplay struggles are well-documented this year (and in my view, the only legitimate cause for concern around this team), they remain absolute upper-echelon 5-on-5 players, and should be fine in the near future.

---

There's the old sports adage that "injuries are never an excuse," but no one really points out that the second part of that saying should really be "for not trying your hardest." The simple fact of the matter is that while first and second liners are first and second liners for a reason, career AHL journeymen are career AHL journeymen for a reason as well. They're just not good enough to make a team effective. Vancouver is seeing this right now, as the offensive output is the lowest that it's been in years and the team has lost its chokehold on the slowly improving Northwest division. Injuries may not be an excuse, but they're a damn good reason for not winning.

The silver lining in all of this is that Jordan Schroeder, Andrew Ebbett, Steve Pinizzotto, Andrew Gordon, Tom Sestito and the newly recalled Bill Sweatt aren't in the plans going forward. Reinforcements are coming in the form of a former Selke trophy winning two-way star centre, the #1 prospect the Canucks have in their system, and if recovery goes well, an elite play-driving 2nd line winger. Management is aware of the holes that need to be filled on this roster, and will undoubtedly attempt to fill these holes this week as the trade deadline looms. This lineup isn't fundamentally flawed, the players haven't completely forgotten how to play, and Alain Vigneault is still a good coach. Now is not the time for panic, but that doesn't mean you shouldn't be concerned.
Posted by at No comments:

Tuesday, 26 March 2013

Lies, Damned Lies, and PDO

I'll preface this entry by saying that no, I'm not going to rail against the PDO machine. Unsustainable percentages due to randomness are a part of hockey, and regression toward the mean has been proven and demonstrated by people much smarter than myself (like the 2011-12 Minnesota Wild. Minus the "smarter" part). This purpose of this post is to address some inaccuracies I think surround PDO, as well as look at some of the concerns I have with leaning so heavily on one metric as an indicator of "luck." With that out of the way, let's get down to business.

This post was inspired in part by something Justin Bourne wondered yesterday:
Which provoked this response from one Rob Pizzola:
Well, to me at least, there are a couple of things wrong with this. The first being that while PDO may be a good indicator of team luck, it's not necessarily a good indicator of individual player luck. This is primarily because on-ice shooting% and on-ice save% are completely unrelated to one another. This should just be common sense. How a goalie performs at one end of the ice should have no bearing on how the goalie at the other end of the ice performs since they're 200 feet apart at basically all times. If you're unconvinced, I have a graph to prove it!

Relationship between team Shooting% and Save% for all teams between 2007-2008 to 2011-2012
As shown by the graph, your shooting and goaltending have nothing to do with one another. Your goalie is going to have his mean save%, and your shooters are going to shoot at some mean shooting%. On a team level, this really is irrelevant. PDO is meant to measure how much of a team's goal differential is due to random variance, rather than more demonstrably sustainable abilities like puck possession, and for the most part, others have shown it does that quite nicely.

The problem starts when PDO is used to explain individual output, like the Pizzola quote above. Comparing Seguin's behindthenet.ca stat lines over his young career, you'll quickly see why his PDO this season is so high:

Top row is 2013, bottom row is rookie season in 2010-2011
What Seguin's benefiting from this year is an unusually high on-ice save%. Now, Tuukka Rask sports an impressive .927 at evens for his career (that's Roberto Luongo territory), so a higher on-ice save% than normal should be expected. Compared to last year, Seguin's higher PDO is being driven by a factor he has basically no control over.

So this season, he's experiencing a boost in Corsi, a higher on-ice shooting%, an elevated PDO, but a decline in production from 2.69 EV pts/60 last year to 2.26 EV pts/60 this season. Just from looking at PDO, Seguin should be having good luck, and instead his actual even-strength output is down across the board. PDO does not capture why, nor does it show that he's actually getting lucky in the offensive end of the ice. Therefore, it cannot be concluded that his production will change either way based solely on a high PDO.

(Since the purpose of this post is to demonstrate that PDO as it is frequently used doesn't always capture good and bad luck on an individual player level, exactly why Seguin's production is down isn't really relevant to this discussion. I suspect though that it's because his individual shooting% is below what his true talent mean could be. Behind the Net shows that he's shooting below 6% this year, compared to the 8.3% he shot last year. Of course, there's also the possibility that he's David Booth 2.0. Also note his frequent linemate Brad Marchand shooting near 14% in each of the last two years. That's probably the source of the high on-ice shooting% number Seguin's PDO has enjoyed.)

The second real problem I have with PDO on an individual level is the idea that all players will have an individual mean PDO of 1.000 and any deviation from that is due to variance. We already know that on-ice shooting% and save% are unrelated, so let's ignore the part of PDO that a player can't control and assume that on-ice save% will regress towards your goalie's true-talent mean save%. This leaves a player's on-ice shooting% as the aspect of PDO a player can control to some degree.

If I remember what I read a while ago, Gabe Desjardins argued that there was no such thing as discernible shooting skill, and all offensive output was the result of either puck possession, luck, or a combination thereof. Someone else (I want to say it was David Johnson of HockeyAnalysis.com, but I'm really not sure and I don't want to put words in anyone's mouth) disagreed, arguing that elite players demonstrate consistently superior shooting abilities. I tend to agree with this dissenting opinion, largely because I live in a market that sees David Booth play more frequently than anyone else and holy hell that man can't shoot the puck in the net. As a result, I have a tough time believing that there is no difference in skill between him, a 4th line crash-and-banger, and say, career 17.3% shooter Steven Stamkos or career 15% shooter Sidney Crosby.

In fact, this discrepancy between "talented" and "stone-handed" forwards is illustrated quite nicely in some analysis Tyler Dellow posted this morning as I was writing the first part of this up. Also looking at stuff inspired by Justin Bourne (basing the good player/bad player distinction on Corsi), he posted this table:
Courtesy of Tyler Dellow at mc79hockey.com. Go read his things and laugh at his beloved Oilers plight.
The biggest thing I took from this table is that the shooting% of first liners do exceed that of fourth liners by quite a significant margin (note: it looks like Tom Awad found this distinction too, as Eric Tulsky pointed out in the comments of Dellow's analysis). For the purposes of this argument, let's make the assumption that the average individual mean on-ice shooting% for each first line player is 9.22%, and the average individual mean on-ice shooting% for each fourth liner is 6.24% as Dellow found in his analysis. This means that for a Boston Bruin first liner like Tyler Seguin, they can reasonably expect a mean PDO of 9.22% + Tuukka Rask's 92.7% save%, for an expected individual PDO of roughly 1.02, which is nearly exactly what his PDO was last season. By comparison, a Bruins fourth liner can expect a PDO of around 0.989 with the difference being attributed to finishing skill.

As this is the case, 1.000+ PDOs for first line forwards are not due simply to good luck. Similarly, sub-1.000 PDOs for third and fourth line players are not necessarily due to poor luck either. A player with a PDO of exactly 1.000 - which we consider to be operating at exactly at his expected output with no good or bad bounces - may actually be experiencing a fair amount of variance and can still regress to his individual mean either way, depending on their talent.

So, from all this stuff, there are two main takeaways:
1) PDO does not capture luck on an individual skater level.
2) The mean that PDO can be expected to regress to is unique to each player, and is influenced mainly by that players role and shooting ability.

With these points in mind, I don't think using PDO to make judgments on an individual player's point production is particularly wise. It's a relatively small and seemingly obvious distinction to make, but still an important one nonetheless. It's why I tweeted this to Justin Bourne yesterday:
PDO is good for the broad-brush analysis on a macro-scale ("the Ducks' record is unsustainable!"), but it's "predictive" power doesn't really carry over to a micro-scale, because you're not dealing with nice, round numbers anymore and PDO's two components are completely unrelated to each other. Regression will always happen, but it's not as cut-and-dry as the familiar "it will regress to 1.000!" mantra, at least not on an individual level.

---

As as aside from the above discussion, something Thomas Drance wrote today got me thinking. Mostly, it was this quote:
But that capital is evaporating as quickly as Vancouver's strangehold on the Northwest Division. Part of the reason that the court of public opinion has slowly begun to turn against Mike Gillis is, in part, that for the first season since 2008-09 Vancouver's PDO (PDO is the sum of a team's shooting percentage and save percentage, and functions as a shorthand measurement of puck luck) isn't two standard deviations above the mean. 
Emphasis is mine. Basically, and this is idle speculation on my part, why can't Vancouver maintain an elevated PDO? On the surface, this is a dumb question, since the answer is "regression." But, as Tyler Dellow and Tom Awad have found, more skilled players have the ability to maintain higher on-ice shooting%, and in Vancouver, Alain Vigneault has done nothing but feed the Sedin twins offensive zone starts over the past three seasons. In fact, both Dellow and Awad identify Daniel Sedin as one of the few players in the NHL that has elite puck possession and finishing skills.

With the Sedins seeing the lions share of Vancouver's offensive zone starts, it means that the Canucks will see a higher proportion of their shots on goal taken by 9%-10% shooters than other teams do. Of course, this also means less offensive zone time for the below average finishers on their roster. This would mean, just from a simple weighted average, the Canucks and Alain Vigneault can effectively inflate their team shooting% above what it would normally be under more traditional player deployments (I also think AV is the main driver behind the Sedin's strong Corsis, but that's a topic for another day). This, coupled with elite even strength goaltending provided by Roberto Luongo the past few years, would lead to a higher than 1.000 mean PDO.

Of course, this could mean that the "elavated" 1.011 PDO Vancouver is operating at so far may in fact be below the Canucks' actual mean, and there could be room to regress upwards. It's an exciting thought for a Canucks fan, and an interesting one too, especially considering the recent (and favourite of Thomas Drance) quote Lawrence Gilman gave Elliotte Friedman:
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.
Could this PDO manipulation through player deployment be the influencing of "percentage results" that Gilman's talking about here? It's possible, but the Canucks are understandably coy about their analytic black box. That's not going to change anytime soon, either. I mean, these aren't the Toronto Raptors we're talking about.

---

One more thing, I still think PDO should stand for "Percentage-Driven Output." Give it a real fancystat name already.
Posted by at No comments:
Subscribe to: Posts (Atom)