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03-14-2013, 04:12 PM
garret9's Avatar
Join Date: Mar 2012
Location: Vancouver
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I already placed this elsewhere, but I thought it was good to place here.

The whole concept of the statistics I use are:
* To win a game you have to out-score the opponent
* Scoring increases and decreases due to number of chances for each side and the quality of chances for each side
* Some variables are more repeatable and controllable than others, and some variables have been shown to have more correlation to winning than others.
* Luckily for hockey analysis, the stat that is the strongest in correlating with winning, and most repeatable, and is one of the more accurately counted stats is shooting differentials.
* You can split differentials from simplest (+/- being goals, SF/SA being shots) to more complex (Fenwick being goals, shots on goal, missed shots, all per 60 minutes of play and Corsi adding in blocked shots)

Here's an example of how strong the correlation is:
I took shots for and subtracted shots against — coming up with the overall shot differential for each time in each season for the last 5 years. I then used that as the explanatory variable in a regression against standings points. What were the results?

In short, the results are unequivocal: there is an incredibly strong relationship between shot differential and standings points. I’ve outlined the P-value of this regression in red. What does that even mean? Well, you remember that you need a P-value lower than 0.05 to assert statistical significance, right? The lower the number, the more confident you are in a statistical relationship. The P-value in red is 0.000000000000015. Or, I can say with 99.9999999999985% confidence that there is a statistically significant positive relationship between shot differential and standings points.
I forgot to site the source

When I use terms like luck or puck-luck, some posters get offended stating that there is only the luck that you make... Here's a good comment from nhlnumbers on the subject:
People who object to the term "luck" as used here don't seem to understand what it means. The word comes with an unfortunate connotation of "not deserving" or "completely random". Outcomes in professional sports are weighted probabilities, not destinies, so it's entirely possible for the better team to lose on any given night or even over a brief sample of games, like a best of seven series, for no other reason beyond variance. There are also other influences beyond the control of the players, coaches and GM's of course: the officiating, injuries to key players, etc. Sports are interesting not only because of the action, competition and violence, but because they are a boiling cauldron of uncertainty. Sometimes the underdog wins. And sometimes it's not because of any particular failing of the favorite.
I agree with the denotation that it's not randomness in the outcomes but weighted probabilities.

Last edited by garret9: 03-15-2013 at 02:27 PM.
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