Thursday, February 19, 2015

The Niklas Bäckström Conundrum for Minnesota

Source: Winona Daily News
While researching what options the Buffalo Sabres should pursue in goal for the 2015-16 season, I started to consider why Devan Dubnyk should be a serious option for the team next season. I am probably jumping the gun on this but, after reading Kevin Woodley's article on the new technique has Dubnyk added to his game, I would consider Dubnyk to be a low cost, high upside bet to maintain his success next season. But before writing that speculative post, the likeliness that the Wild will keep Dubnyk past this season deserved it's own story - which brings us to the situation they face with their longest tenured goaltender, Niklas Backstrom.

The Wild, for their part, won't worry about the possibility of resigning Dubnyk until after the season. Potentially complicating that decision is the fact the Wild already have a combined $5.3 million committed to Darcy Kuemper and Niklas Backstrom for next season. Should Minnesota resign Dubnyk, the easy call (in theory) is to move on from the Backstrom, who is 13 years older than Kuemper and is in the midst of his third straight season with a sub .920 5v5 save %. Given goalies have been found to rapidly regress in their mid 30s, the 37-year old Backstrom's $3.4M cap hit is one that Minnesota should want to move on from, independent of whether they intend to resign Dubnyk or not.

Complicating things for Minnesota is that Backstrom has almost definitely become what Down Goes Brown calls a "negative value guy" - a player that, if Minnesota were to place on waivers tomorrow, would go unclaimed due to his current contract. Part of that is cap uncertainty - many hockey fans are well aware that Canadian dollar fluctuations and the NHLPA's unwillingness to escalate next year's Salary Cap at the expense of increasing escrow creates uncertainty in how much (if any) the cap will rise for the 2015-16 season. But most of that is because Backstrom's deal is in February 2015 is just a poor contract, one that is paying more for past performance than the future.

Wild fans that would love to test whether Backstrom is actually a negative value guy and waive him will be disappointed, as Backstrom's No Movement Clause prevents him from getting sent to Minnesota's AHL affiliate in Iowa like Josh Harding was earlier this season (though even if he were able to be waived, only $925K of Backstrom's $3.4M AAV would saved against the cap).  Also complicating the situation is Backstrom's modified No Trade Clause; though it's uncertain how many teams he has the right to block a trade to, the player's happiness in Minnesota would likely make him unlikely to waive it for a team he really doesn't want to play for - with the odds being good that teams with the cap space and willingness to take on his full deal if Minnesota were to throw in a positive asset (e.g., Buffalo) are on Backstrom's NTC list.

Among the teams that Backstrom can be traded to, an opposing GM would demand Minnesota hold most, if not all, of the 50% cap hit ($1.7M) GMs are allowed to retain in trades under the current CBA. Veteran backup goalies with no trade protection generally don't fetch much of a return, such as Peter Budaj this past fall (for Eric Tangradi) and Ilya Bryzgalov last season (for a Minnesota 4th round pick). As Backstrom's Modified NTC gives him the some ability to control his own destiny if he's traded, the Budaj and Bryzgalov returns seem like a best case scenario for the Wild.

One last option the team could explore is buying out the remaining year of Backstrom's contract this summer. While CapGeek's closure in January keeps me from being able to link the buyout calculator math from that site, we can manually calculate the buyout as I did in a post a few weeks ago when talking about what Buffalo should do with Cody Hodgson. Those curious on the instructions for calculating a buyout should refer to this Blueshirt Banter post, but the penalty for buying out Backstrom can be calculated as such:
  • Per Spotrac, Backstrom is due $4M in Year 3 (2015-16) of his 3-Year, $10.25M deal (AAV of $3.417M). The buyout amount is 2/3 of the remaining salary ($2.667M). That $2.667M buyout amount is spread evenly over the double the remaining length of the deal - i.e., the next two years, so $1.333M each for the 2015-16 and 2016-17 seasons.
  • For 2015-16, the $1.333M buyout amount is subtracted from Backstrom's $4M salary to calculate a "cap savings" of $2.667M. The cap savings are then subtracted then out of the AAV that gives us a $750k cap penalty ($3.417M - $2.667M) for the 2015-16 season.
  • For 2016-2017, the cap penalty is the $1.33M buyout amount.
Given the near zero value the Wild are likely to get back for Backstrom in a trade (even with holding salary), the cost of buying out Backstrom is potentially easier to stomach. Due to his contract being slightly backloaded, Backstrom's cap penalty is actually lower next season than the year that exceeds his original deal. But therein lies the issue with buying out Backstrom. Consider the players the Wild need to resign in the summer of 2015:
  • UFAs: Kyle Brodziak, Keith Ballard, Nate Prosser, Ryan Carter, Stu Bickell
  • RFAs: Mikael Granlund, Marco Scandella, Erik Haula
Though RFAs Granlund and Scandella are due for sizable raises from their sub respective $900K and $1.025M deals, both are in line for more modest raises than, say, Cody Hodgson in Buffalo. Additionally, all of Minnesota's UFAs should be affordable to resign and/or readily replaceable. As it is, Minnesota has just $56.6M tied up in 15 players for 2015-16 - including Backstrom. In fact, a Backstrom buyout saves Minnesota $2.667M in AAV for 2015-16, versus a trade saving Minnesota as little as $1.67M in addition to the asset the Wild likely have to give up to trade the salary. As a result, those extra buyout savings can be allocated to resign their upcoming FAs and/or another goaltender - say, Dubnyk - with higher upside than Backstrom. 

Where the real issue potentially comes is the the 2016-17 season, when the $1.333M buyout charge will have to be added to a Wild cap that is projected to consist of the elevated Granlund and Scandella salaries, Dubnyk's (or another goalie's) cap hit, any 2015/2016 UFA signings, and four more important RFAs Minnesota will be in line to resign that summer: Jared Spurgeon, Matthew Dumba, Jason Zucker and Darcy Kuemper. In translation - buying out Backstrom may hurt the 2016-17 cap more than keeping or trading Backstrom at a reduced rate hurts the 2015-16 cap.  


Source: USA Today

Alternatively, the Wild could decide to keep Backstrom for next season, perhaps due to a mix of loyalty to the nine year Wild veteran and wishful thinking that Backstrom can regain his form as part of a platoon. Minnesota could then borrow a page from the 2013 Canucks' playbook and trade away the goaltender in waiting (24-year old Kuemper) for a good asset as opposed to trading away the veteran goaltender with a toxic contract (Backstrom) in a salary dump. This option is fairly appealing for the Wild if they have internally given up on Kuemper. As to whether they should trade Kuemper: though his .905 5v5 save % through 29 GP this season is concerning given the success Dubnyk has had behind the same Minnesota defense, the Wild do not have much in the goaltending pipeline beyond Kuemper, who still has the athleticism and upside to be a full-time starter in Minnesota. The Wild only have to look to Dubnyk to see that, with some work on his technique this summer, Kuemper's development can be brought back on track.

Of course, another scenario is Dubnyk's 11-2-1 run in Minnesota this past month is not only unsustainable, but the inevitable drop off in his play is so severe that the Wild decide to walk away from him altogether come June. But even in that case, the decision for the Wild next year should be what other goalie they should acquire over the summer to compete with Backstrom and/or Kuemper for the starter's job next season. Because whether it's Dubnyk or someone else, Mike Yeo and the Wild deserve better than going into next season with the horrid Kuemper / Backstrom tandem that nearly sunk the Wild's 2014-15 season before a rejuvenated Devan Dubnyk brought the team back from the brink.

Sunday, February 8, 2015

Rationalizing a Cody Hodgson Buyout

Source: The Vancouver Province
In this week's 30 Thoughts (Point 4), Elliott Friedman was the first I've seen raise possibility of a Cody Hodgson buyout this summer though the idea had previously been suggested on the SabresNoise blog. At first, the idea seemed a surprising given Hodgson being one of the few Sabres on long term deals with offensive upside (e.g., leading the Sabres in points for the 2013-14 season, albeit with just 20 goals and 24 assists in 72 GP). But given his abysmal stat line (2G and 6A in 51GP, tied with Torrey Mitchell for 13th on the team as of February 8thand mediocre possession numbers (0% Corsi Rel on a league worse 37.1% 5v5 Corsi team, despite having a relatively higher number of offensive zone starts and weaker quality of competition) more than halfway into the 2014-15 season, it is an idea that has become fun to explore as evidenced by recent blogs in favor of and against jettisoning Hodgson. Being a healthy scratch against the Islanders tonight (his third time this season) should only fuel the talk of a Hodgson buyout between now and the start of free agency. 

Source: War-On-Ice; Minimum 200 Minutes Played as of February 8th
First off, with CapGeek & its handy buyout calculator out of business, we will have to do some manual math to calculate why a Hodgson buyout could be an enticing proposition for Buffalo this summer. A 2010 post from Blueshirt Banter has a straight forward bulleted list of how a buyout is calculated, and the first bullet point was the main reason Friedman had highlighted a Hodgson buyout as a real possibility: a player under 26 can be bought out for 1/3 of his remaining salary vs 2/3 of the remaining salary for a player over 26. With Hodgson turning 25 in February, the direct cost of buying out Hodgson significantly raises from this upcoming offseason to the next. 

Prior to the start of the 2013-14 season, Hodgson signed a 6 year, $25.5M extension, working out to a $4.25M AAV. Unlike the kind of front loaded deals that we are used to seeing older players sign, Hodgson's deal was back loaded such that his actual salary was $3M in Year 1 (2013-14), increasing $0.5M every season until he is scheduled to make $5.5M in Year 6 (2018-19). As a result, the Sabres would be on the hook for buying out 1/3 of the remaining $19M in salary he's owed ($6.3M total) as opposed to the remaining total AAV. Should the Sabres hypothetically wait until the summer of 2016, the Sabres would be on the hook for 2/3 of the remaining $15M ($10M total):

Source: CapGeek data via the Wayback Machine 
Sabres Owner Terry Pegula may very well not want GM Tim Murray to spend another $6M this summer for someone to not play in Buffalo following last summer's compliance buyouts of Ville Leino and Christian Ehrhoff, who are respectively being paid $7.33M and $12M over the next dozen or so years to not play professional hockey in Buffalo. However, let's assume that Mr. Pegula would indeed drill another oil well to buyout Hodgson's remaining albatross of a contract if that is what it takes to win a Cup in Buffalo. So how much would a buyout affect Buffalo's salary cap? As shown in the below table, the $6.3M Hodgson is owed will be spread over twice the remaining 4 years of the contract (working out to $0.79M per season through 2022-23). For the years within the contract, the cap hit is equal to the difference in the $4.25M AAV and the "cap savings", which is the annual difference in Hodgson's salary and the $0.79M owed to him (e.g., in 2015-16, the cap saving are $3.21M, which is $4M in salary minus the $0.79M cost). For a summer 2015 buyout, the years that extend beyond the contract are just equal to the $0.79M owed Hodgson:

Source: CapGeek data; black data represents cap penalties, red data represents cap credits
Now contrast the cap hits vs. 2016. From 2016-17 to 2021-22, the buyout would cost an additional $0.88M, a small but not insignificant salary cap penalty for the Sabres to incur. The team's current rebuild means it will be awhile before they would/should realistically want to spend to the cap ceiling; additionally, Buffalo's willingness to spend to cap ceiling since Mr. Pegula's purchase of the team versus the internal cap the team had set under Tom Golisano gives the Sabres more flexibility to incur a buyout cost if that's what the franchise sees fit. An escalating salary cap - which has been predicted by James Mirtle to hit $100 million by the time the current CBA expires in 2022 - would further decrease the relative cost of having Hodgson's bought out salary on the books. 

However, the Sabres almost certainly expect to be contenders by the time Hodgson is due a new contract, let alone any years the bought out contract would sit on the cap. How high the cap will rise over the time frame also remains more in flux now than at the end of 2013 due to a couple different reasons. First off, the NHLPA will remain hesitant to inflate the salary cap at the expense of increasing escrow, the amount of salary the NHL holds out of player paychecks, as explained in the same Friedman piece from this week. Secondly, a strong American dollar multiple years into the future directly affects the value of revenues collected in Canada and would place downward pressure on the salary cap rising in future years. To a lesser extent, a strong American dollar also weakens the profitability of future global events the NHL is pushing forward as revenue drivers in coming years, including the return of the World Cup of Hockey (to take place in Toronto and Montreal in 2016) and a proposed "Ryder Cup" in European markets

But back to the main issue at hand: what is Tim Murray to do with Cody Hodgson? The cap savings from moving from Hodgson this year vs. waiting are tempting. But should the Sabres jettison one of the few players with pure scoring talent on their roster, particularly one who under the right system could finally reach the potential to play the two-way game so desired in today's NHL? 

To Hodgson's credit, this season has been a confluence of bad factors that many players of his tier would also falter under. For starters, Hodgson's 2 goals can largely be explained by his 3.0% overall shooting percentage (3.6% 5v5) thus far in the 2014-15 season, significantly below his career average of 10.8%. Part of it is also Hodgson is shooting the puck at a lower clip this season. With just 67 shots through 51 GP, Hodgson's 1.3 shots per game would be the lowest of his career as a full time NHLer (he had 9 shots over 8 games as an AHL call-up for Vancouver during the 2010-11 regular season). Another issue has also been the subtraction of Thomas Vanek and Jason Pominville from the roster, who Hodgson played the majority of his relatively successful 15G 19A lockout-shortened 2013 season. Adjusting for zone starts during that 2013 season, Hodgson was better at driving possession when he was on the ice with Vanek and Pominville than without. Conversely, Vanek and Pominville also played with Hodgson than without, a credit to Hodgson's ability to be more than just a passenger with Top 6 talent. 

Replacing Vanek and Pominville on Hodgson's line has primarily been Chris Stewart (a soon to be ex-Sabre largely more renowned for his size than for his ability to score or drive possession) and a revolving door of wingers and centers, as Hodgson himself has spent time this season alternating between the wing and center. Following the expected exodus of forwards such as Stewart, Torrey Mitchell and Drew Stafford at the trade deadline, Hodgson could get a chance to close the season out on a higher note by getting more playing time back in the Top 6 of the lineup. As it is, Hodgson is one of the "unluckier" players on Buffalo, with a PDO of 97.6 due to the Sabres scoring just 5% with him on the ice at 5v5 (vs. 8.1% 5v5 overall).  

In my own opinion, there's enough evidence to believe that if Hodgson were to be placed with better line mates and was having better luck shooting the puck, we'd more so be talking about what Buffalo could possibly trade Hodgson for than whether he should be bought out or not, which I ultimately don't believe the Sabres should do. However, the question is whether Buffalo should keep him long-term, and I am inclined to lead towards no on this. Though Hodgson can again be a 20 goal scorer when playing with quality line mates, Coach Ted Nolan seems insistent on burying Hodgson on the bottom 6. Perhaps part of that is bad defense, but if the Sabres are to trade Hodgson they will need to showcase him with Top 6 forwards to convince teams with a need for scoring wingers that he is worth the majority of his $4.25M AAV in a trade with the Sabres.

Speaking of trading Hodgson, as it's inconceivable seeing a team taking on 100% of Hodgson's contract for a few reasons. First off, another team would almost certainly require sending back a similarly bad or even worse contract to Buffalo if they were to acquire Hodgson at full cost, making the proposition of buying out Hodgson more appealing. As they did with the Vanek and Pominville trade, the Sabres would almost certainly offer to hold salary to maximize the return they get for trading Hodgson. Secondly, Hodgson's back-loaded contract structure makes him slightly more desirable to big market teams than small market teams, who are more likely to prefer back loaded deals with lower AAVs than salary that help them cost effectively reach the cap floor. But since many big market teams are so close the cap ceiling as is, prospective Hodgson acquires will want to acquire him at the lowest AAV possible. 

At this moment in time, Hodgson is probably what you would consider to be a "negative value guy" as defined by Sean "Down Goes Brown" McIndoe - a guy who, if Buffalo were to place on waivers tomorrow would go unclaimed at a $4.25M AAV given this season's play. Yet part of that is due to teams' ability to acquire guys at lower AAVs than the deals they were originally signed to thanks to the new CBA. Trading Hodgson within the next year or two at a pro-rated salary after his luck will have taken a turn for the better provides Buffalo the best chance at turning him into another asset. Even if an eventual Hodgson trade turns out to be a salary dump, any salary Buffalo holds back in a trade would come off the books at the end of Hodgson's current contract in 2019 versus 2022 or 2023 - a significantly more advantageous year to be free of dead money given where Buffalo hopes to be in their current rebuild.

So in conclusion, Murray's decision on Hodgson's future should be when/if to trade Hodgson as opposed to when/if to buy him out, and part of that will involve getting Ted Nolan to bring Hodgson back into the Top 6 of the lineup where he will be most productive (and hence most valuable). Sure, Hodgson is most likely not the Top 6 center the Sabres hoped they acquired in exchange for Zack Kassian at the 2012 trade dealine. Yet despite his current scoring struggles, below average faceoff numbers and reputation as a soft, "injury prone" player, at a lower AAV there's definitely still a place for Hodgson in the NHL as a depth scoring forward, like he was his rookie season in Vancouver. That place is just not in the bottom 6 of a rebuilding Sabres team.

Sunday, March 2, 2014

Sloan Recap: Oh, Brian Burke

Source: National Post
Last week, I wrote at length about how hockey could learn a thing or two from basketball in using optic-tracking cameras and wearable devices to capture new data streams. At MIT's Sloan Sports Analytics Conference (SSAC) last weekend, MLB announced that Milwaukee, Minnesota and the New York Mets would be debuting field-tracking cameras to help quantify player positioning and movement from multiple directions, with all stadiums having the cameras installed by 2015.

Mark Newman's article on MLB.com does an excellent job of breaking down the implications for baseball, and many of these would be directly applicable to hockey. When it comes to quantifying general athletic attributes such as speed, positioning, and hand-eye, optic-tracking cameras are helpful towards more accurately quantifying all sports. The potential for optic-tracking video cameras was introduced at Sloan's hockey analytics panel by Eric Tulsky of SB Nation who, as always, fought the good fight for advancing the discussion and application of statistical analysis in hockey.

Alas, Brian Burke showed up and, well, this oral history from a few attending media members should tell you how it went (note: some strong language thanks to Brian Burke).

Quick Hit: The Economics of Trading Christian Ehrhoff

Source: Canucksarmy.com
Well, that escalated quickly. With Ryan Miller and Steve Ott shipped off to the Blues, the Tim Murray era is off with a bang with more moves expected ahead of the March 5th trade deadline. Forthcoming UFAs Matt Moulson and Henrik Tallinder are expected to follow Miller and Ott out of Buffalo, with virtually every player (save for Zemgus Girgensons) available for the right price. That would include the two newest Sabres - Jaroslav Halak and Chris Stewart - acquired from St. Louis, as well as Christian Ehrhoff, who submitted his list of eight teams he wouldn't accept a trade to earlier this week.

As with Pominville last year, Ehrhoff's no trade list does not necessitate that he will be traded before Wednesday, but gives Murray the ability to see what he can get in return from the 21 teams where Ehrhoff can be traded. Though the the salary cap will increase for the 2014-15 season (speculation says the 2012-13 level of $70 million is a fair estimate), just how much is still unknown. As a result, GMs enter Wednesday's trade deadline weary of taking on term - to which Ehrhoff's remaining 7 years will be an issue. However, the bigger issue will be Buffalo's willingness to lose certainty over Ehrhoff's cap recapture penalty in the expected event that he retires before the term of the contract is up.

From a hockey perspective, Ehrhoff has been one of the team's few bright spots during his tenure with the Sabres. Sabres blog The Hosers did a really nice job last year showing how much better Ehrhoff's 2013 Sabres teammates controlled the puck with Ehrhoff on the ice vs. without him:

 I'd imagine Sekera would look favorably on an Ehrhoff trade to Carolina.
Source: TheHosers.com

While Ehrhoff's possession stats are down this year, he has taken on greater responsibility in defensive zone starts and playing time on the PK due to hemorrhaging of the Sabres roster over the past calendar year. Should the Sabres try to push their luck and bottom out in 2015 to win the Connor McDavid sweepstakes, trading away Ehrhoff is arguably the second most effective way to do that after trading Ryan Miller. The reason for keeping Ehrhoff, however, may less so lie in staying competitive than the structure of his contract providing little incentive to move him

With regards to trading Ehrhoff, sure, what team wouldn't want to free themselves of seven years worth of salary? Well, as many hockey fans know, teams that benefited from the weighting / front-loading of contracts seven years or longer stand to be penalized the amount of cap savings upon the player's retirement thanks to the cap recapture rule under the new CBA. To date, the Sabres have benefited $10 million from the difference in Christian Ehrhoff's contract relative to his cap hit. The good news for trading away Ehrhoff is that the Sabres have already realized the whole benefit from front loading the deal. The bad news for Buffalo is that the cumulative cap benefit remains at $10 million until the 2017-18 season - at which point it only decreases to $9 million:


The 2018-19 season is when Ehrhoff will start making $1 million dollar in annual salary and likely mark his retirement from NHL if Miikka Kiprusoff's recent retirement is a cautionary example. Even if Ehrhoff plays past 2018, his retirement before 2021 would leave Buffalo with a per year cap penalty $3 million:


Under cap recapture, should the Sabres trade Ehrhoff, the cumulative cap benefit (i.e., $10 million) will be frozen and spread out following the player's retirement from the NHL. While this would have little effect on the Sabres cap situation should Ehrhoff retire ahead of the 2018-19 season like his contract incentives him to, his retirement following the 2018-19 or 2019-20 seasons could be considerably damaging to Buffalo's cap situation:


Contrast Ehrhoff's situation with Marian Hossa's for a minute. The Blackhawks, who have realized a cumulative cap benefit of $13 million to date, have incentive to "freeze" the benefit and trade Hossa this season, as opposed to incurring an additional $5 million cap benefit over the following two seasons:



While Chicago, like Buffalo, incurs the risk of Hossa retiring with 1-2 seasons remaining on the deal and hurting Chicago's cap situation the most in those seasons, the upshot of Hossa likely retiring with four year left on the deal (prior to 2017-18, when he is scheduled to start making $1 million in annual salary) would cost Chicago about $1 million less per season should they trade Hossa instead of holding on to Hossa until his retirement date. Given Hossa is one of the few players on Chicago without a no trade clause and the Blackhawks already used compliance buyouts on Steve Montador and Rostislav Olesz in the 2013 off-season, his contract could very well push him out the door this upcoming offseason.

Source: NHL.com
Circling back to the Sabres, there is an upshot to the dilemma of trading Christian Ehrhoff. If Tim Murray knows that Ehrhoff isn't in Sabres' plans past 2018, or if the player is likely to want a trade before that time, then the Sabres can confidently trade him when they can get the best value knowing that the future cap recapture penalty is a sunk cost. Given Ehrhoff is 31, that time is likely to be this trade deadline or off-season, where Ehrhoff has more useful seasons at a modest $4 million cap hit remaining in the NHL versus dead years.

As far as an acquiring team is concerned, there is no cap recapture or long-term salary left on the books from acquiring Ehrhoff - the biggest risk is that he outruns his usefulness before he decides to retire. For an acquiring team, there could even an out here: a hypothetical buyout of Ehrhoff for 2017-18 or a subsequent season, when his annual salary falls to $1 million a year, is very reasonable in terms of money coming out of the owner's pocket as the buyout cost teams roughly two-thirds in salary. Given the buyout additionally counts roughly two-thirds in cap hit, a buyout of Ehrhoff's contract could even be an attractive proposition for a small market team struggling to keep up with an escalating salary floor. But I am getting ahead of myself.

Given Ehrhoff's on ice play, affordable cap hit and and modest $3 million cap penalty in what could eventually be a $90 million salary cap world, I would personally lean towards not trading him. The potential for the $10 million cap recapture to be concentrated in just one year is extremely frightening. However, given the likeliness that Ehrhoff and the Sabres will wish to part ways with each other before Ehrhoff's cap penalty will start to reduce (2017), the best course of action is probably to accept the cap penalty as a sunk cost and shop Ehrhoff to the highest bidder. Whether Tim Murray can find a trade worth taking is another story.

Sunday, February 23, 2014

DataPuck: A Primer to Hockey’s Place in the World of Big Data

At next weekend’s MIT Sloan Sports Analytics Conference, research papers on the “datafication” of baseball and basketball will show how those respective sports are utilizing new data streams and techniques to deliver new analytical insights on evaluating player performance. Hockey fans should not expect the same.

"Tilted Ice", the only hockey paper to be accepted for Sloan, will presents an insightful look on how teams (although not individual players) change on-ice behavior in third periods of contests. There will additionally be a panel on Friday dubbed “Hockey Analytics: Out of the Ice Age” that will discuss the use of analytical judgement for individual player evaluation. If contrasted with recent developments in basketball, hockey is still a ways away from a warm period. 

Take, for example, EPV (short for Expected Possession Value), a methodology to be presented in Sloan  research paper "POINTWISE" that utilizes optical tracking data from the SportVU cameras the NBA installed earlier this year in collaboration with STATS LLC to evaluate player performance and decision making. Another Sloan 2014 research paper, "The Hot Hand", additionally utilizes the NBA's optical tracking data to evaluate a different metric of performance (streakiness). While the use of optical tracking cameras in the NBA is old news, the NBA's D-League recently announced a few weeks ago that four teams will be piloting the use of small, wearable devices for tracking player movement and other bio-related indicators.
   
For a hockey fan, the NBA’s utilization of "big data" collection and analysis techniques is a woeful reminder of just how far behind hockey analytics are relative to its peers. How to define big data? For tech companies, the phrase is generally used to describe data whose size exceeds the CPU memory of traditional databases and analytics tools – a bit of a silly definition, since this just means today’s big data analysis tools are tomorrow’s data analysis tools.  Perhaps a better definition comes from the 2013 Financial Times Book of the Year finalist "Big Data”, which suggests the revolution is not behind the tools themselves. While increasingly sophisticated business intelligence and analytics tools help to make big data analysis more economically feasible for businesses and individual statisticians alike, the real revolution is in the world’s shifts towards capturing far more streams of data – all the data – and empirically analyzing it. 

The NBA’s pioneering usage of machine-generated data (as opposed to human-generated data from sources such as emails, photos, tweets etc.) highlights what I believe will be the most common way sports will expand to harness new data sources. While POINTWISE and The Hot Hand will spark discussions at Sloan around additional use cases for basketball, the papers should additionally spark discussions around the use of optic-tracking camera in other fluid, fast-paced sports - i.e., hockey. 

The Next Wave of Hockey Datafication


If I were a betting man, the hockey analytics panel at Sloan will only briefly touch on the idea and potential of optic-tracking cameras for the NHL and hockey, should the question be raised. Based on the panel description, the discussion will more so focus on expanding adoption and usage of currently hockey analytics tools (such as Corsi, Fenwick and PDO helped popularized by Behind the Net and Extra Skater) among hockey decision makers. However, the usage of machine-generated data to create the hockey equivalent of EPV model with 'big data' is an intriguing idea for the NHL to theoretically pilot.

The idea of an EPV isn't new. At Sloan last year, a research paper presented a methodology, dubbed Total Hockey Rating (THoR), that aimed to evaluate NHL players based on the idea that each player contributed to the probability of that a goal is scored and prevented. Of course, the study that suggested Tyler Kennedy was the third most valuable player in the NHL from 2010-2012 should raise some eyebrows. While THoR helps to push forward hockey analytics by presenting sound judgment in its methodology, its usage of hits methodology reflects the real weakness facing hockey analytics – the stats that are easily measurable don’t necessarily reflect what a player's true value could be away from when and where a notable hockey play happens that machine-oriented data could easily replicate.

Like in POINTWISE, an EPV algorithm leveraging machine-oriented data could be devised for hockey that tracks the probability of scoring for every moment a player enters the offensive zone (or if a player has the puck any zone if Ondrej Pavelec is in net). EPV additionally presents a framework to calculate the value of “entry passes, dribble drives and double-teams” in basketball; in hockey, the same could be done for evaluating pieces of hockey strategy be it dump and chases, shot selection and line chemistry (I’m looking your way, Chris Kunitz). One could imagine a world where a trail blazing hockey coach plug players into a zone model similar to the half court model provided by POINTWISE co-author Kirk Goldsberry in this Grantland piece and, leveraging billions of rows of machine, calculate success probabilities of player selection and formation on power plays and penalty kills. Models for the antithesis of EPV – perhaps expected defensive value – could be developed to identify players best at limiting high percentage shot opportunities and creating turnovers. Not only will machine-generated data help overcome the need to use Corsi and Fenwick as proxies for puck possession, but it will additionally help more accurately identify which players correlated with both possession and takeaway ability (not to mention turnover liability).  

While the potential of machine-oriented data to help devise coaching strategy and support GMs in player transaction decisions has seemingly unlimited potential, its application by coaches "on the fly" seems unpractical given the need for reaction prompt decision making (i.e., the home team has an 8 second limit on making line changes in between whistles; the away team has just 5 seconds). The infiltration of iPads and tablets behind hockey benches, as has become common place among baseball managers such as Joe Maddon, is probably around the corner. However, their use will probably be reserved for drawing plays with styluses and streaming instant video replay than plugging in variables to calculate probabilities, which sports such as baseball and football have greater use for given the longer lag time in between plays. 

Data derived from wearable devices as the D-League is testing would additionally help hockey organizations derive new insights on players, given that models to evaluate speed, acceleration, endurance and other bio-related data in basketball are directly transferable to hockey. As noted in Zach Lowe’s article, the collection of bio-related data would raise concerns for the union, with any sort of application of optic-tracking cameras or wearable devices to be meticulously negotiated by Donald Fehr and the NHLPA. However, the discussion of wearable devices, and optic-tracking video cameras for that matter, are still in the future without further buy of more sophisticated analytics among hockey decision makers in general.

Hockey Analytics Today

For the hockey analytics world, the good news is that acceptance and adoption is gradually coming in the sport even if it is lagging its peers. Most notably, the Penguins detailed at a predictive analytics conference in Toronto last year how they’re working with the Sports Analytics Institute to create a player evaluation system leveraging player location and shot probabilities to create predictive systems for goals for/against and lifetime value. The model's first application in practice came in 2011, when the Penguins acquired James Neal from the Dallas Stars in what is arguably one of the most lopsided trades in recent memory. In January, the New Jersey Devils threw their hat into the analytics ring with the announcement of hiring of a Director of Analytics that will report directly to Lou Lamoriello (although it remains to be seen how or if the old-school Lamoriello will leverage the person ultimately hired for the position).

While possession stats are useful to help hockey fans better evaluate their favorite NHL teams and players (with their application in lower AHL, NCAA and junior levels providing a new opportunity to scout players), it’s still early days in the datafication of hockey and its acceptance in hockey circles. 'Intangibles’, ever a point of contention in social media fights between analytical and old school hockey types, should highlight an opportunity for hockey analytics to create new models in favor of arguing with old school thought. As papers such as the Hot Hand suggest, not every old notion should be dismissed where "advanced statistics" fail to exhibit any correlation. Rather, all that could be needed is more data to suggest a correlation does exist.

Take New York City for example, which has embraced big data analysis techniques to identify illegal, over occupancy buildings that are more prone to deaths in the case of fires  Highlighted in the aforementioned "Big Data" book, New York City’s first “Director of Analytics” Mike Flowers highlights an exchange with a senior fire chief concerning an apartment with multiple red flags based on his team's algorithm, with the senior fire chief's gut claiming a building was likely passable because the brick exterior was new. Instead of brushing off the old guard’s hunch and sticking with the team's existing algorithm, Flowers’ team took note of the senior chief’s insight and quantified brick exterior investments through city building permits.

Ultimately, the datafication of hockey presents an exciting opportunity for blogs like this one to grow with the infusion of hockey related data both on and off ice, and maybe get a hockey decision maker or two to listen along the way. While currently available analytics help to deliver new deeper insights for evaluating player and team performance than +/-, it is important to realize their limitations and develop methodologies to better analyze "the coolest game on Earth". 

At the very least, it's more entertaining than watching the Sabres for the foreseeable future.  

Sunday, March 10, 2013

Rating Hockey Players: Hits and other Statistical Jargon


So I decided to start blogging on a whim this weekend. Partially because I didn’t want anyone to think I’m the michaelbarba.blogspot.com that offered unthoughtful opinions in 2009 on legalizing weed as a solution to boost economic growth, and partially because I had opinions beyond 140 characters on things I read on the internet where the things I’m interested in – such as hockey, economics, statistics, technology and coffee – intersect.

There was an SAP-sponsored paper that was presented at the MIT Sloan Sports Analytics Conference in Boston last weekend that caught my attention titled “Total Hockey Rating (THoR): A comprehensive statisticalrating of National Hockey League forwards and defensemen based upon all on-iceevents”.  What the paper tries to present is a, “reliable methodology that can quantify the impact of players in creating and preventing goals for both forwards and defenseman” (Shuckers and Callo 1, 2013). After that, the paper identified nine on-ice action events to quantify THoR, including shots, turnovers and hits. The paper smartly isolated biases for several different considerations – how takeaways / giveaways are calculated (with home scorekeepers tending to favor the former statistic), offensive vs. defensive zone starts, talent level of goalies and other players on the ice, and shot location selection (providing higher weights to higher percentage shots). Overall, it’s an extremely well orchestrated study, but there are a few major criticisms I have for THoR, in addition to the grammatical mistake from the paper’s abstract I quoted above (defensemen should be plural). Chiefly: the inclusion of hits in THoR’s methodology.

The original purpose of measuring hits as a statistic was to treat it as a turnover metric – for example, if Shea Weber knocks Patrick Kane off the puck and Roman Josi gains possession as a result, Weber is rewarded with a hit. However, the stat has become a subjective tool that the scorekeepers can reward regardless of outcome. For example, say Kane and Patrick Sharp are on a 2 on 1 vs. Weber and Weber hits Kane right after Kane sets up Sharp for a goal. The scorekeeper can award Sharp the goal, Kane the assist and Weber the hit.

The statistic is further diluted by home scorekeeping bias. Consider this random Red Wings – Blue Jackets game from February 2012 in Columbus. Although the Blue Jackets lost 5-2, they managed to “out hit” the Red Wings 33-2. Take a look at team hits for the 2011-12 season; the Phoenix Coyotes were fifth in the league at home in hits, but only ninetieth on the road. Either the Coyotes are extra fired up to play to arenas where announced attendance was 72.5% last season, or the (more obvious answer) the scorekeepers are biased towards the home team.

Biased home scorekeeping can extend to other stats beyond hits as well that the authors did not account for. From the Sabres - Rangers game last weekend in MSG, Drew Stafford scored a rare goal off directly off a Mikhail Grigorenko faceoff that the Rangers “won”. The book Scorecasting finds that the “home court” advantage a team maintains is reflective of a) the away team’s travel schedule (in the NBA, MLB and NHL) and b) subjective decisions made by referees. In theory, the ability to draw penalties and get on the power play favors the home team as a result of the referee bias. The referee bias can also extend to non calls favoring the home team, a la this Matt Duchene goal against the Predators last month that was just a bit offside (Side note: in fairness, this memorable non call from last rewarded the away team).

In a more extreme case of biased home scorekeeping, Jeff Marek from Sportsnet in Canada recounted a story on the Marek vs. Wyshynski podcast a few weeks ago from the 1997-98 season when Glen Sather was trying to trade defenseman Dan McGillis. To boost McGillis’ trade value, Sather had the Oilers scorekeeper tally extra hits for McGillis to make potential suitors think he was a hitting machine – at the trade deadline, the Philadelphia Flyers acquired McGillis and a second round pick from the Oilers for Janne Niinimaa, who gave the Oilers five productive seasons and an All-Star game appearance in 2001. (Side note: In fairness, while McGillis was not the hitting machine the Flyers thought they had acquired on their blue line, McGillis did give the Flyers five quality seasons and won the Barry Ashbee Trophy awarded to Philadelphia’s top defenseman in 2001).

Hits’ lack of meaningfulness is not necessarily the study’s fault, but including it in THoR considerably weakens its usefulness.  However, what is not accounted for in THoR’s methodology hurts the study just as much as including hits. Part of this is beyond the study’s control – x y coordinates for where every single player is on the ice during a goal, which undoubtedly affects the probability a shot will go in, are not recorded. But there are a couple of measurable oversights that weaken THoR – dummy variables for power plays, and who is coaching the team.

Including dummy variables for power play situations (whether it be 5 on 4, 5 on 3, or 4 on 3) is a bit of an academic point. The study factors in time spent on the power play and multiplies it against the league average; but as of this writing, the Anaheim Ducks are more than twice as likely to score with a man advantage than the Buffalo Sabres are (29.2% vs. 12.2%). Because power play situations are mutually exclusive from regular situations, the effect can be easily isolated with a dummy variable.

Though no mention of it is made in the study, it should be notable that Alexander Ovechkin (who scored 70 goals over the course of the two observed seasons) is completely missing from the study’s Top 50 players list (just as it should notable that Tyler Kennedy is Number 3 behind Alexander Steen and Pavel Daystuk). But wouldn’t the affect of the Capitals firing their run and gun head coach Bruce Boudreau midway through the 2011-12 season in favor of the defensive minded Dale Hunter have a negative effect on Ovechkin and other Washington Capitals that didn’t make the list such as Niklas Backstrom, Mike Green and Brooks Laich? (Side note: Alexander Semin was the only Capital to make the list at #49, and is evidently not too missed in the Washington locker room these days). It is notable THoR treats players as separate if they switched teams over the course of the study; this logic should additionally apply to when their coach is switched.  

As well, measuring players by purely goals for and goals against is an idea that is a sharp departure from what Corsi (arguably the most popular advanced hockey metric) chiefly accounts for to rank individual players – shot attempt differential (which is also utilized as a proxy for puck control).  Of course, there would be little to no difference in findings between THoR and Corsi if they both measured the same metric. But by measuring players on creating and preventing goals alone, you can’t control for luck’s contribution as well as you can with shot differential, chiefly because goals are not independent of the goalie. Accounting for whether Jonathan Quick (who led all goalies with 40 or more starts last season with a 1.95 GAA) or Vesa Toskala (who is Vesa Toskala) is in net will have a difference on goal probability. But Quick still let in 133 goals last year; without insanely detailed information, you would have to go back and look at all 133 goals scored on Quick to determine if Player X created the goal, or scored as a result of luck (such as a good rebound, a defensive letdown or poor positioning on the goalie's part). 

Ultimately, any methodology will have its shortcomings. At the very least, this paper has presented an alternate way to think about what makes up a top NHL player, and is a good first pass of developing a “reliable methodology” it wishes to develop. But unless you’re Tyler Kennedy or his agent, I imagine this study will have little more influence on shaping any business decisions in the NHL as this blog will.