Number Chains - May 15, 2012 Links

Kent Wilson
May 15 2012 11:42AM

 This new, regular feature on NHLNumbers will share interesting stats-related posts from around the web every week.

  • First up is a non-hockey article from Deadspin. Confessions of an NBA scorekeeper looks at how certain results in pro basketball are "fudgible" and how even earnest or well-meaning stats counters can be influenced to favorably adjust things like assists or blocks for a certain team or player on any given night.

The NHL has similar problems when it comes to accounting for shots on or at the net (although a dubious second assist sometimes slips through the net as well). Back in 2009, Sunny Mehta showed how the Devils shot counter totals only seemed to have a passing resemblence to reality. Vic Ferrari and Tom Awad also detailed the difference in shot counting between teams across the league that same year.

Gabriel Desjardins did a systematic take-down of Madison Square Garden's stats counter three years ago as well.  The problem with the Rangers home counter is actually shot location - with shots being counted sometimes 15-20 feet closer to the net than they actually were. Gabe followed up a year later to see if the issue was persistent. Alas, pucks were still magically being shot from a lot closer to the net than anywhere else in the league.

Aside from not being able to fully trust shot totals from certain rinks, these biases affect measures like corsi, fenwick and any study seeking to determine shot quality or shot independent goaltender ratings. As a result, it's usually a good idea to restrict large scale investigations that including shot/block totals and locations to away locations because the assumption is the various biases and errors will more or less cancel each other out. It cuts the sample in half, but until the league can improve the quality of its data there isn't much of an alternative.

  • Next up is an interesting new stats developed by SnarkSd of Fear the Fin: P+Corp (points + corsi over replacement level). Snark describes his measure as
At it's heart it's a simple stat that serves as a good substitute or comparison piece to the current gold standard of player evaluation, GVT. The beauty is in it's ease of calculation, which requires looking up only 3 (or 4 for Defensemen) stats from the main Behind The Net page. My underlying assumption is that ice time increases with line status, ie. top lines are given the most ice time, but everything else falls out from detailed data collection. I didn't fine tune these numbers so the best players are at the top of the list, this is evidenced-based hockey analysis.
... In addition, it is well integrated with replacement level. A score of 0 will always be our baseline replacement level talent. As P+CORP increases (and theoretically decreases) talent level increases as compared to (ie. over) replacement level.

The explanation and discussion is quite detailed, so make sure to take look. It is a great attempt at creating a new, integrated stat that can measure players versus replacement level.

  • Hockey Prospectus and FlamesNation contributor Rob Vollman recently released leaguewide player usage charts. Also called Ozqoc charts, these chart a players usage by looking at his individual quality of competition versus zone start ratio. At a glance they tell you how easy or difficult each players assignment was last year. 

Related: Thomas Drance recently looked at Alain Vigneault's deployment of the Canucks roster this past season through an Ozqoc chart and compared his tactics to the rest of the league. The extreme difference in circumstances between the bottom and top of Vancouver's roster becomes readily obvious in this article.  

  • Finally, Gabriel Desjadrins re-vists the Winnipeg Jets decision to take Mark Scheifele over Sean Couturier in the entry draft last June. The decision was a head scratcher at the time and seems even less defensible one year out. Bonus helping of regret and self-doubt for the Jets scouting staff: the massive season by Sven Baertschi, who was taken a few picks alter by the Calgary Flames.

If you have any stats-related links of interest, fele free to share in the comments or send them to Kent.Wilson@gmail.com for future inclusion.

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Former Nations Overlord. Current FN contributor and curmudgeon For questions, complaints, criticisms, etc contact Kent @ kent.wilson@gmail. Follow him on Twitter here.
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#1 Derek Jedamski
May 15 2012, 03:26PM
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I have to wonder why more coaches don't employ Vigneault's extremist use of zone starts. Granted, his extremist ways are a encouraged by the fact that you have two of the best scoring forwards in the league on your team along with one of the best defensive forwards.

However, I still wonder why a coach like Lindy Ruff doesn't utilize a similar system. Before the Guastad a trade, the shutdown line of him, Kaleta, and Gerbe was quite effective. However, the trio still never dipped below 40% offensive zone starts (Patrick Kaleta was the only one that even fell below 45%) and Tyler Ennis was tops at the other end with a 57.7% ozone start rate.

Then you have a player like Vanek only starting in the offensive zone 54% of the time, behind guys like Leino and Hecht. Why not take some of those ozone starts from Gaustad/Kaleta/Gerbe and feed them to players like Vanek/Ennis/Hodgson.

The other team's top line will be starting in your own zone more often that not anyways, get your shutdown line out there then and leave the ozone faceoffs to primarily your top offensive threats.

It's an oversimplified view of it but Ruff has, at times, had the tendency to try to fit square pegs into round holes. I would love to see Thomas Vanek be a great 2-way forward as much as the next guy, but I'd also like to see him be put in a position to score 35+ goals per year, which he has the talent to do.

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#3 Cam Charron
May 15 2012, 04:57PM
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Brought it up on Nation Radio this week, but there are some coaches (Barry Trotz, Dave Tippett) who find success with hard player-on-player matchups.

I think a big difference between Corsi Rel QoC or Ozone% is something coaches should strive for and give their very best players the toughest minutes and get their scorers easier opportunities. Zone starts are easier to do.

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#5 Robert Vollman
May 16 2012, 08:58AM
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Thanks for the mention!

And Thomas Drance's subsequent analysis is truly top drawer, showing the potential of Player Usage Charts.

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