Corsi vs Goals when predicting conference finalists

Every year I’ll see a tweet like the following and while they frustrates me it also shows me peoples biases. NHL teams that made conference finals ranked No. 2, 6, 7, 8 in score-adjusted Corsi% during regular season. pic.twitter.com/AhJTRQYMHg — Neil Greenberg (@ngreenberg) May 13, 2016 It shows peoples biases because clearly Neil is attempting to defend Corsi, something he has invested himself in over the years, by showing the value of Corsi in predicting conference finalists. It is frustrating because it isn’t really telling us the whole story. Sure, seeing #2, #6, #7, and #8 teams make the semi-finals seems

» Read more

Review of Beleskey and Williams impact on save percentages

Last off season two of the better wingers on the unrestricted free agent market were Matt Beleskey and Justin Williams. In the analytics community Williams is generally lauded as a possession king and and undervalued player while Beleskey was pointed out as the unrestricted free agent most likely to be over paid (turned out he ended up with a lower than expected deal but still some figured he was still over paid). At the time I wrote a summary of these two free agent wingers and said while Williams had dominant possession statistics he has generally had a negative impact on his

» Read more

Who Deserves the Norris Trophy?

The NHL award that seems to be generating the most interest and discussion this season is the Norris Trophy given to the best defenseman. In some circles Drew Doughty seems to be the favourite because he is having a great season in a great career on a team having a great year. Others are picking Erik Karlsson because of his dominant offensive season for a defenseman, one that few defensemen can match in the history of the game. Brent Burns is having almost as good of an offensive season but for a playoff team so his name gets thrown into

» Read more

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 conventional wisdom. That is how we learn new things. We make observations, we ask questions about their relevance, we investigate and we either toss out the new idea or we

» Read more

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 league in which teams are all deploying tactics in order to optimize their SAT% and pummeling a small number of holdouts who either don’t accept analytics orthodoxy or simply aren’t

» Read more

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 the future are two different questions. The reason for this is due to the fact that lack of persistence might be due to players changing teams or changing roles. What

» Read more

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 infinite amount of time in all score scenarios. Under this scenario there is no need to make considerations for sample size, quality of teammates, quality of competition, zone starts, score

» Read more

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 out there and that goes for every player,” he continued. “But the amount of things [Karlsson] does right and the amount of things he does to impact his team in

» Read more

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: 0.69 Split half correlation for Sh%: F: 0.10/D: 0.05 — Matt Cane (@Cane_Matt) February 6, 2016 @hockeyanalysis Over 3 year periods you’re correct, CF% does have a lot of other

» Read more

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 the threat that Benjamin Wendorf will never engage with me again (how could I live with myself if that happened), I decided that I must finally investigate this regression thing

» Read more
1 2 3 34