Anecdotes and validating statistical models

I often get criticized by others in the hockey analytics community, particularly on twitter, when I through out a piece of data that runs counter to conventional analytical thinking and raise a question as to whether it means something or not. Sometimes I do it because I believe in what I am saying but other times I do it because I think we should constantly be challenging and testing current…

March 18, 2016
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Is possession hockey providing diminishing returns?

Ian Cooper sent me a link to an article he recently wrote how hockey analytics has driven the importance of puck possession hockey which in turn can change the dynamics of hockey analytics. In his article he showed that in recent years there has been a smaller spread in team CF% talent which he believes is due to a higher percentage of teams focusing on puck possession hockey. That’s more consistent with a…

March 15, 2016
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Correcting a post on shot quality and save percentage revisited, again

It is beginning to become a regular occurrence but someone over at Hockey Graphs has attempted to debunk a theory/stat/opinion of mine and once again failed in their procedure for doing so. This time Garret Hohl tried to debunk Sv% RelTM as a useful statistic by looking at the persistence and predictability of Sv% RelTM over time despite the fact that just a month ago I suggested that evaluation of the past and predicting…

March 10, 2016
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Evaluating Player Evaluation Metrics and Expected Goal Models

  Think about the perfect scenario where we have an infinite sample size. A scenario where every player plays an infinite amount of ice time with and against every other player. In fact, every 6-player combination of 3F-2D-1G plays against every other 6-player combination an infinite amount of ice time. Players start an infinite number of times in the offensive zone, defensive zone and neutral zone and they play an…

March 3, 2016
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Is Erik Karlsson a good Defender? Does it matter?

I read an article today discussing whether “role player” still have a role in the NHL today. A significant part of the discussion revolved around Erik Karlsson, whether he is a good defensive player, and essentially whether it mattered. Former offensive NHL defenseman Brian Leetch discussed Karlsson’s play and that overall he contributes everything a team could ask of him. “It’s a game of mistakes. Something’s going to go wrong…

February 26, 2016
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Are we predicting the future or analysing the past?

So, yesterdays post created an interesting, and mostly positive to my delight, response. Credit goes out to Matt Cane who hit the nail on the head in figuring out the response I was looking for. @hockeyanalysis So I think a key point to note here is that CF% shows a lot more consistency within season. — Matt Cane (@Cane_Matt) February 6, 2016 @hockeyanalysis Split half correlation for CF%: F: 0.74/D:…

February 7, 2016
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Observed stats are bad, regressed stats are good

That’s what I have been told. The fact that you are still basing your arguments on observed data means that, even now after at least six years of exhortations from successive generations of people who have tried to work with you and help you, you do not understand what it means to regress your data. I refuse to engage any longer till you learn to do this. —Benjamin Wendorf Under…

February 6, 2016
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Hockey Analysis, War on Ice and the future of stats sites

The big news in the online Hockey Analytics community yesterday, aside from the Ottawa Hockey Analytics Conference, was the Andrew Thomas announcement that war-on-ice.com will be shutting down in the upcoming months. Although in many respects War on Ice was a competitor to my site (stats.hockeyanalysis.com and puckalytics.com) it was also a great site that was developed for different reasons and served a different purpose. My sites were developed by…

January 17, 2016
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What baffles me most in hockey analytics

I am always astonished by how much I get critiqued about shot quality and whether it exists or not and whether it is important or not. I get even more criticism if I ever bring up the idea that defenders can have an ability to boost save percentage. To me this is the most baffling thing I have come across in hockey analytics. Let me explain why. I would hazard a…

January 14, 2016
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Are you adequately accounting for Shot Quality in your Expected Goals model?

The other day on twitter I questioned whether an existing expected goals model by @DTMAboutHeart adequately accounted for shot quality. This tweet it seems prompted a response from the Hockey Graphs crew in which they all take turns downplaying the importance or shot quality. We already know that the impact of shot quality (context + skill) is miniscule in comparison to other factors –pet bugs   The question to ask then…

January 13, 2016
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