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

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

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

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

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

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

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

Muzzin, Phaneuf, and the impact of roles on possession stats

The other day I wrote about what I hope for from hockey analytics in 2016. It largely focused on more investigation into the impact of coaching and specific roles players play have on individual statistics. For the most part hockey analytics has developed by looking at what team statistics correlate well with team success and then transferring those observations to player evaluation (i.e. Corsi correlates with winning so good players should…

January 8, 2016

Schenn, Jones, Weber and Sv%RelTM

I get criticized a bit (I might even say mocked) for suggesting that defensemen have the ability to influence their goalies save percentages. It surprises me some because to me the idea that defenders can’t is just a bit far fetched. A defender that turns the puck over a lot at key moments has to have a negative impact on his goalies save percentage. Conversely one who doesn’t would boost his…

January 6, 2016

My hope for Hockey Analytics in 2016

The last couple of years have been eventful for the hockey analytics community and hockey analytics has definitely gone main stream. The past year or so has seen some interesting developments including more investigation into shot quality (Scoring Chances by war on ice, expected goals from @DTMAboutHeart, etc.) , some interesting enhancements in goalie evaluation, and the passing project led by Ryan Stimson has shown some interesting results and could provide many…

January 4, 2016