2017 Playoffs Thread

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 13:

Outcome | Prob
PIT in 5 games|14.0%
PIT in 6 games|20.0%
PIT in 7 games | 23.1%
OTT in 7 games|11.6%
OTT in 6 games|15.0%
OTT in 5 games|9.8%
OTT in 4 games|6.5%
PIT wins | 57.1%
OTT wins|42.9%
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 14:

Outcome | Prob
ANA in 5 games|10.5%
ANA in 6 games|15.4%
ANA in 7 games|20.6%
NAS in 7 games|16.8%
NAS in 6 games | 22.6%
NAS in 5 games|14.2%
ANA wins|46.5%
NAS wins | 53.5%
 

Sabretooth

Registered User
May 14, 2013
3,104
646
Ohio
And in round two, the SRS model sucked:

Winner | Prob
NYR|54.9%
OTT|40.4%
WAS|82.3%
PIT|48.4%
NAS|41.3%
STL|29.5%
ANA|61.0%
EDM|58.8%
NAS|50.1%
ANA|49.2%
OTT|33.1%
PIT|37.5%
TOTAL | 5.9 series (out of 12)

Yikes.

Was thinking about this a bit. I think you're being too hard on your model. I don't think just adding up the winning team percentages is the correct way to measure your model. Even if all 12 teams favored by the model won, you'd have only added up to 7.3 series out of 12.
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
That's true! Although ideally, the most predictive models will decrease the odds of a type II error (and correctly picking the winning team) while decreasing the odds of a type I error (incorrectly picking the wrong team). That is, a perfect model will correctly identify the winning team 100% of the team, with a 0% chance of an error. (Of course) that isn't possible in any reality, but then the question becomes how close can we get?

So in other words, if I say that Team A has a 52% chance of winning a series (and they do), I should get less credit than if I say that Team A has a 65% chance of winning a series (and they do).

I'll also clarify that this type of model - the SRS algorithm - is in the public domain, and so I can't take credit. In particular, there are multiple adjustments that can be made to improve the performance of the model, and I post these to engender a bit of interest in the sort of speaking that "I bet I can do better, and I'm going to try".

(My main use for the SRS algorithm - aside from promoting competition here - is that it's a pretty reasonable retrospective team strength, and so I use to it measure goaltender schedules and similar. For instance, if a team is rated as +0.40 goals/game, that may not be as predictive for future events as it could be, but it's very representative of what they've already accomplished.)
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After games of May 15:

Outcome | Prob
PIT in 5 games|21.1%
PIT in 6 games | 24.5%
PIT in 7 games|23.6%
OTT in 7 games|11.5%
OTT in 6 games|12.9%
OTT in 5 games|6.3%
PIT wins | 69.3%
OTT wins|30.7%
 

Sabretooth

Registered User
May 14, 2013
3,104
646
Ohio
That's true! Although ideally, the most predictive models will decrease the odds of a type II error (and correctly picking the winning team) while decreasing the odds of a type I error (incorrectly picking the wrong team). That is, a perfect model will correctly identify the winning team 100% of the team, with a 0% chance of an error. (Of course) that isn't possible in any reality, but then the question becomes how close can we get?

So in other words, if I say that Team A has a 52% chance of winning a series (and they do), I should get less credit than if I say that Team A has a 65% chance of winning a series (and they do).

I guess what I'm getting at is that you really don't know if the model sucks (bad probabilities) or if it was just an unlucky roll based on 1 result. The favored team in your model won their series 5 out of 12 times, which would be expected to happen approximately 9-10% of the time even if your assigned odds were perfect. It's a more likely result than correctly predicting >9 series winners. 7 correct predictions would have been expected (still less than 1 in 4), but none of 6, 7, 8, or 9 should have been surprising. 5 correct predictions was the 5th most likely result. A perfect 12 for 12 only happens 0.2-0.3% of the time given your assigned odds. The model could be absolutely perfect and this could still be a perfectly valid result.
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
True - and any models that promise 90% accuracy per series are either selling something, or don't understand the role of luck.

With that said, I'd like the "out of the box" SRS algorithm to do better than 50% at least. ;)
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 16:

Outcome | Prob
ANA in 6 games|10.3%
ANA in 7 games|19.7%
NAS in 7 games|16.1%
NAS in 6 games | 28.6%
NAS in 5 games|25.2%
ANA wins|30.1%
NAS wins | 70.0%
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 17:

Outcome | Prob
PIT in 6 games|19.5%
PIT in 7 games | 27.8%
OTT in 7 games|14.8%
OTT in 6 games|22.2%
OTT in 5 games|15.8%
PIT wins|47.2%
OTT wins | 52.8%
 

Talks to Goalposts

Registered User
Apr 8, 2011
5,117
371
Edmonton
True - and any models that promise 90% accuracy per series are either selling something, or don't understand the role of luck.

With that said, I'd like the "out of the box" SRS algorithm to do better than 50% at least. ;)

That was a quality burn on SAP's claims as NHL's official data company. I'm curious if it was deliberate or not.
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 18:

Outcome | Prob
ANA in 6 games|24.0%
ANA in 7 games | 27.8%
NAS in 7 games|22.9%
NAS in 6 games|25.3%
ANA wins | 51.8%
NAS wins|48.2%
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 19:

Outcome | Prob PIT in 6 games | 36.0%
PIT in 7 games|31.7%
OTT in 7 games|16.6%
OTT in 6 games|15.7%
PIT wins | 67.7%
OTT wins|32.3%
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
Algorithm correctly picked both series.

Through three rounds:

Winner | Prob
NYR|54.9%
OTT|40.4%
WAS|82.3%
PIT|48.4%
NAS|41.3%
STL|29.5%
ANA|61.0%
EDM|58.8%
NAS|50.1%
ANA|49.2%
OTT|33.1%
PIT|37.5%
PIT|76.2%
NAS|50.3%
TOTAL | 7.13 series (out of 14)
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
And, ladies and gentlemen, your 2017 Stanley Cup Finals:

Outcome | Prob
PIT in 4 games|10.0%
PIT in 5 games | 19.5%
PIT in 6 games|17.7%
PIT in 7 games|19.0%
NAS in 7 games|11.3%
NAS in 6 games|12.2%
NAS in 5 games|7.0%
NAS in 4 games|3.3%
PIT wins | 66.1%
NAS wins|33.9%
 
May 31, 2006
10,457
1,320
Do you use some sort of logistic regression (fitted with past outcomes) to calculate the probabilities?
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
Do you use some sort of logistic regression (fitted with past outcomes) to calculate the probabilities?

For each team, I calculate the variance of their SRS statistic (since the SRS produces a point estimate for each game, you can see how off it was for each team).

If you then make the (admittedly simplifying, but not particularly bad) assumption that each team's SRS is normally distributed, then the difference of the two is also normally distributed, and the probability of a win lines up with where that distribution crosses zero (after including home ice advantage).
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 29:

Outcome | Prob
PIT in 4 games|16.5%
PIT in 5 games | 26.1%
PIT in 6 games|18.7%
PIT in 7 games|16.8%
NAS in 7 games|10.1%
NAS in 6 games|8.6%
NAS in 5 games|3.2%
PIT wins | 78.1%
NAS wins|21.9%
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of May 31:

Outcome | Prob
PIT in 4 games|27.4%
PIT in 5 games | 31.7%
PIT in 6 games|17.0%
PIT in 7 games|12.6%
NAS in 7 games|7.3%
NAS in 6 games|4.1%
PIT wins | 88.7%
NAS wins|11.3%
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of June 3:

Outcome | Prob PIT in 5 games | 31.4%
PIT in 6 games|25.3%
PIT in 7 games|21.2%
NAS in 7 games|12.9%
NAS in 6 games|9.2%
PIT wins | 77.9%
NAS wins|22.1%
 

Doctor No

Registered User
Oct 26, 2005
9,250
3,971
hockeygoalies.org
After game of June 5:

Outcome | Prob PIT in 6 games | 30.5%
PIT in 7 games|30.3%
NAS in 7 games|19.4%
NAS in 6 games|19.8%
PIT wins | 60.8%
NAS wins|39.2%
 

Ad

Upcoming events

Ad

Ad