NHL Team Power Ratings and Predictions (SRS Algorithm)

[oljimmy]

Hey DN,

Very interesting metric. Wanted to ask a question: at this time last year, the three bottom teams were below -1.000 and several were knocking on that door. Now, last-place Columbus is showing -0.571. On the flip-side, 2nd-place Dallas' .590 would have only been good for 6th place at this time last year. Does this help to confirm what many people have been saying, namely, that parity is way up in the league this year?

 

[Doctor No]

Thanks!

And I agree completely about parity - I've calculated these values back through 1972-73 (because I use them to estimate goalie schedule strengths on my site), and this is *by far* the most closely bunched the teams are.

Speaking of disparity, the top eight strengths I have in my database (1972-73 to present) are all from 1970s seasons. Bottom's a bit more spread out, thanks to some new expansion entries, but the 1970s are strong there as well.

Top overall: 1976-77 Canadiens, who would be expected to win a game against an "average" team by 2.65 goals on neutral ice.

Bottom overall: 1974-75 Capitals, who would be expected to lose a game against an "average" team by 3.05 goals on neutral ice.

 

[oljimmy]

Wow. So this is indeed a very strange year.

Last question, how do the great 80s Oilers teams rank? I would have thought that at least one version would have cracked the top ten but I guess not.

 

[Doctor No]

Some very good Oilers teams in the mix - here's the full list:

YEAR|STRENGTH
1979-80|-0.313
1980-81|0.100
1981-82|1.163
1982-83|1.374
1983-84|1.594
1984-85|1.466
1985-86|1.221
1986-87|1.147
1987-88|1.099
1988-89|0.257
1989-90|0.674
1990-91|0.107
1991-92|-0.164
1992-93|-1.222
1993-94|-0.545
1994-95|-0.957
1995-96|-0.817
1996-97|0.041
1997-98|-0.091
1998-99|-0.018
1999-00|0.168
2000-01|0.282
2001-02|0.315
2002-03|0.037
2003-04|0.179
2005-06|0.286
2006-07|-0.460
2007-08|-0.090
2008-09|-0.183
2009-10|-0.784
2010-11|-0.916
2011-12|-0.331
2012-13|-0.267
2013-14|-0.754
2014-15|-1.002

In practice, I develop separate ratings at home and on the road, but these are the straight average of the two.

 

[Doctor No]

NHL data through January 27, 2016 (the all-star break). Home-ice advantage is down to +0.239 goals/game.

Team | 2015-16 Goal Diff | 2015-16 Schedule | 2015-16 Strength
Washington|

1.149​

|

-0.052​

|

1.097​

|
Florida|

0.551​

|

0.013​

|

0.564​

|
Dallas|

0.580​

|

-0.062​

|

0.518​

|
Chicago|

0.472​

|

-0.039​

|

0.432​

|
Tampa Bay|

0.265​

|

0.043​

|

0.309​

|
Boston|

0.327​

|

-0.030​

|

0.296​

|
NY Rangers|

0.265​

|

0.007​

|

0.272​

|
San Jose|

0.271​

|

-0.018​

|

0.252​

|
Los Angeles|

0.327​

|

-0.075​

|

0.252​

|
NY Islanders|

0.255​

|

-0.033​

|

0.222​

|
Minnesota|

0.122​

|

-0.016​

|

0.106​

|
Montreal|

0.040​

|

0.029​

|

0.069​

|
Colorado|

0.019​

|

0.038​

|

0.058​

|
Pittsburgh|

0.021​

|

-0.001​

|

0.020​

|
St. Louis|

0.019​

|

-0.036​

|

-0.017​

|
Detroit|

-0.041​

|

-0.025​

|

-0.066​

|
Nashville|

-0.040​

|

-0.034​

|

-0.074​

|
New Jersey|

-0.080​

|

-0.029​

|

-0.109​

|
Carolina|

-0.235​

|

0.033​

|

-0.202​

|
Anaheim|

-0.213​

|

-0.023​

|

-0.236​

|
Ottawa|

-0.320​

|

0.082​

|

-0.238​

|
Winnipeg|

-0.286​

|

0.028​

|

-0.258​

|
Vancouver|

-0.340​

|

0.059​

|

-0.281​

|
Philadelphia|

-0.383​

|

0.074​

|

-0.309​

|
Toronto|

-0.417​

|

0.079​

|

-0.338​

|
Buffalo|

-0.440​

|

0.090​

|

-0.350​

|
Calgary|

-0.417​

|

0.049​

|

-0.368​

|
Arizona|

-0.306​

|

-0.087​

|

-0.393​

|
Edmonton|

-0.540​

|

0.079​

|

-0.461​

|
Columbus|

-0.588​

|

0.097​

|

-0.491​

|

Capitals look great.

 

[Doctor No]

And I've started publishing some retrospective back testing - for games between January 18 and January 27, this is the comparison of what the SRS algorithm expected each team to do, and what they actually did.

Team | Pts Predicted | Pts Achieved
COL|6|10
NAS|5|8
SJS|6|8
ANA|3|6
BOS|7|6
CAR|4|6
FLO|5|6
NJD|5|6
NYR|5|6
PIT|5|6
TBL|5|6
CBS|4|5
STL|4|5
ARI|5|4
BUF|5|4
CHI|6|4
DAL|5|4
DET|5|4
LAK|6|4
OTT|5|4
TOR|5|4
MIN|5|3
VAN|4|3
WAS|3|3
CAL|5|2
EDM|3|2
MTL|5|2
NYI|3|2
PHI|4|2
WIN|5|2

Go Avalanches!

 

[Doctor No]

SRS predictions for February 2, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/2/2016|TOR|BOS|0.87|65%|23%
2/2/2016|NYR|NJD|-0.14|47%|23%
2/2/2016|MIN|NYI|0.35|57%|22%
2/2/2016|MTL|PHI|-0.14|47%|27%
2/2/2016|OTT|PIT|0.50|59%|24%
2/2/2016|FLO|WAS|0.77|65%|21%
2/2/2016|STL|NAS|0.18|53%|24%
2/2/2016|DAL|WIN|-0.54|40%|14%
2/2/2016|CHI|COL|-0.14|47%|19%
2/2/2016|CBS|EDM|0.27|55%|23%
2/2/2016|LAK|ARI|-0.41|42%|22%
2/2/2016|SJS|ANA|-0.25|46%|19%

 

[HitoftheMillennium*]

Woooo... TOR ranks ahead of five teams according to your algorithm.

 

[Doctor No]

For games of February 3:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/3/2016|BUF|MTL|0.60|61%|14%
2/3/2016|DET|TBL|0.61|63%|28%
2/3/2016|CAR|CAL|0.07|51%|24%

 

[Doctor No]

BREAKING NEWS: The Montreal Canadiens just dropped below zero in the SRS algorithm.

One flaw in an SRS is that the standard model considers all games equally. For those of you interested in developing your own predictive algorithm, an easy-to-implement improvement is to weight more recent games higher.

 

[Doctor No]

For games of February 4:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/4/2016|BOS|BUF|-0.32|44%|16%
2/4/2016|MIN|NYR|0.41|58%|20%
2/4/2016|DET|FLO|0.97|68%|27%
2/4/2016|EDM|OTT|0.37|57%|28%
2/4/2016|NJD|TOR|0.02|50%|27%
2/4/2016|NYI|WAS|1.01|69%|21%
2/4/2016|PHI|NAS|0.41|58%|28%
2/4/2016|SJS|STL|0.01|50%|23%
2/4/2016|CHI|ARI|-0.67|37%|23%
2/4/2016|DAL|COL|-0.27|45%|14%
2/4/2016|ANA|LAK|0.76|64%|21%
2/4/2016|CBS|VAN|0.53|60%|25%

 

[Doctor No]

For games of February 5:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/5/2016|PIT|TBL|0.54|61%|21%
2/5/2016|CAR|WIN|0.18|53%|18%
2/5/2016|CBS|CAL|0.47|59%|20%
2/5/2016|ARI|ANA|0.53|60%|20%

 

[Ettan]

Pr(H>0) = Probability of home team winning in the regulation?

Pr(3PG) = Probality of OT/SO

(Pr(H>0) + Pr(3PG) ) - 100 = Probability of away team winning in the regulation?


Right?

 

[Doctor No]

First two, yes.

Last one:
Probability of home team winning in regulation = Pr(H>0) * (1-Pr(3PG)).

Probability of road team winning in regulation = (1-Pr(H>0))*(1-Pr(3PG)).

 

[Doctor No]

Realizing that four games have been played already (although the algorithm doesn't know that), but the mountains were calling this morning...for NHL games of February 6:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/6/2016|WAS|NJD|-0.93|32%|23%
2/6/2016|NYR|PHI|-0.25|45%|28%
2/6/2016|EDM|MTL|0.48|59%|22%
2/6/2016|NYI|DET|-0.17|47%|27%
2/6/2016|BUF|BOS|0.81|65%|17%
2/6/2016|TOR|OTT|0.17|53%|28%
2/6/2016|PIT|FLO|0.94|67%|21%
2/6/2016|MIN|STL|0.16|53%|23%
2/6/2016|SJS|NAS|-0.21|46%|19%
2/6/2016|CHI|DAL|0.34|57%|23%
2/6/2016|CAL|VAN|0.25|55%|30%
2/6/2016|WIN|COL|0.59|60%|11%

 

[Doctor No]

SRS power ratings for NHL games through February 6, 2016:

Team | 2015-16 Goal Diff | 2015-16 Schedule | 2015-16 Strength
Washington|

1.060​

|

-0.026​

|

1.034​

|
Florida|

0.615​

|

0.041​

|

0.656​

|
Chicago|

0.554​

|

-0.030​

|

0.523​

|
Dallas|

0.528​

|

-0.048​

|

0.481​

|
Tampa Bay|

0.353​

|

0.043​

|

0.396​

|
NY Rangers|

0.288​

|

-0.001​

|

0.287​

|
Boston|

0.327​

|

-0.053​

|

0.274​

|
Los Angeles|

0.353​

|

-0.092​

|

0.261​

|
San Jose|

0.196​

|

-0.006​

|

0.190​

|
NY Islanders|

0.180​

|

-0.006​

|

0.174​

|
Montreal|

0.038​

|

-0.001​

|

0.037​

|
St. Louis|

0.055​

|

-0.034​

|

0.021​

|
Pittsburgh|

0.000​

|

0.008​

|

0.008​

|
Colorado|

-0.055​

|

0.040​

|

-0.015​

|
Minnesota|

-0.019​

|

-0.001​

|

-0.020​

|
Detroit|

-0.058​

|

0.003​

|

-0.055​

|
Nashville|

-0.038​

|

-0.034​

|

-0.072​

|
New Jersey|

-0.094​

|

-0.016​

|

-0.111​

|
Anaheim|

-0.080​

|

-0.032​

|

-0.112​

|
Philadelphia|

-0.280​

|

0.068​

|

-0.212​

|
Carolina|

-0.245​

|

0.030​

|

-0.216​

|
Ottawa|

-0.321​

|

0.064​

|

-0.256​

|
Calgary|

-0.294​

|

0.028​

|

-0.266​

|
Winnipeg|

-0.308​

|

0.016​

|

-0.292​

|
Buffalo|

-0.415​

|

0.102​

|

-0.313​

|
Edmonton|

-0.415​

|

0.068​

|

-0.347​

|
Vancouver|

-0.404​

|

0.049​

|

-0.355​

|
Toronto|

-0.451​

|

0.064​

|

-0.387​

|
Arizona|

-0.442​

|

-0.072​

|

-0.514​

|
Columbus|

-0.593​

|

0.069​

|

-0.524​

|

Home-ice advantage is currently measured at +0.232 goals/game.

 

[Doctor No]

NHL games of February 7, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/7/2016|PHI|WAS|1.48|77%|29%
2/7/2016|CAR|MTL|0.49|59%|20%
2/7/2016|EDM|NYI|0.75|64%|25%

 

[Doctor No]

NHL games of February 8, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/8/2016|ANA|PIT|0.36|57%|20%
2/8/2016|NJD|NYR|0.64|62%|25%
2/8/2016|FLO|DET|-0.47|41%|27%
2/8/2016|TBL|OTT|-0.40|42%|24%

 

[Doctor No]

NHL games of February 9, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/9/2016|ANA|PHI|0.25|55%|27%
2/9/2016|EDM|NJD|0.62|62%|28%
2/9/2016|FLO|BUF|-0.65|38%|19%
2/9/2016|LAK|BOS|0.28|55%|23%
2/9/2016|NYI|CBS|-0.56|40%|19%
2/9/2016|TBL|MTL|0.01|50%|19%
2/9/2016|DAL|MIN|-0.24|45%|19%
2/9/2016|WAS|NAS|-0.85|34%|19%
2/9/2016|WIN|STL|0.57|61%|18%
2/9/2016|SJS|CHI|0.59|61%|22%
2/9/2016|TOR|CAL|0.36|57%|25%
2/9/2016|VAN|COL|0.60|61%|24%

 

[Doctor No]

And here's the "live testing" results, from January 18th through February 9th.

These are sorted based upon percent error - for instance, Anaheim was predicted to get 6.85 points in its games, but got 12 (75% more than expected).

Team | Pts Predicted | Pts Achieved
ANA|7|12
CBS|7|11
PIT|9|12
CAR|7|9
STL|8|9
NJD|8|10
NYR|10|12
COL|10|11
NAS|9|10
TBL|9|10
BUF|7|8
FLO|10|11
SJS|9|10
BOS|11|11
CHI|10|10
WAS|9|9
TOR|8|8
DET|8|8
PHI|8|7
DAL|9|8
NYI|7|6
OTT|10|8
CAL|9|6
LAK|9|6
ARI|8|5
VAN|6|4
MTL|10|6
WIN|7|4
EDM|7|4
MIN|8|3

 

[Doctor No]

NHL games of February 10, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/10/2016|OTT|DET|0.42|58%|28%
2/10/2016|NYR|PIT|0.02|50%|21%
2/10/2016|VAN|ARI|0.04|51%|29%

 

[Doctor No]

NHL games of February 11, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/11/2016|LAK|NYI|0.14|53%|23%
2/11/2016|BUF|PHI|0.33|56%|25%
2/11/2016|ANA|CBS|-0.17|47%|18%
2/11/2016|COL|OTT|0.08|51%|19%
2/11/2016|WAS|MIN|-0.85|33%|20%
2/11/2016|BOS|WIN|-0.19|47%|17%
2/11/2016|DAL|CHI|0.22|54%|23%
2/11/2016|TOR|EDM|0.16|53%|28%
2/11/2016|CAL|SJS|0.72|63%|19%

 

[Doctor No]

NHL games of February 12, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/12/2016|LAK|NYR|0.24|54%|21%
2/12/2016|MTL|BUF|-0.28|45%|15%
2/12/2016|PIT|CAR|-0.01|50%|23%
2/12/2016|COL|DET|0.31|56%|21%
2/12/2016|NAS|TBL|0.60|61%|20%
2/12/2016|STL|FLO|0.86|66%|25%
2/12/2016|CAL|ARI|-0.08|49%|22%

 

[Doctor No]

NHL games of February 13, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/13/2016|BOS|MIN|-0.01|50%|21%
2/13/2016|NAS|FLO|0.91|66%|21%
2/13/2016|NYI|CAR|-0.37|43%|25%
2/13/2016|WAS|DAL|-0.29|44%|19%
2/13/2016|ANA|CHI|0.81|65%|23%
2/13/2016|ARI|SJS|0.90|66%|20%
2/13/2016|NJD|PHI|0.14|53%|31%
2/13/2016|OTT|CBS|-0.05|49%|22%
2/13/2016|TOR|VAN|0.38|57%|32%
2/13/2016|WIN|EDM|0.14|53%|19%

 

[Doctor No]

NHL games of February 14, 2016:

Date | Road | Home | E(Home) | Pr(H>0) | Pr(3PG)
2/14/2016|COL|BUF|-0.15|47%|14%
2/14/2016|LAK|NJD|-0.22|46%|26%
2/14/2016|BOS|DET|-0.01|50%|26%
2/14/2016|STL|TBL|0.44|59%|24%
2/14/2016|PHI|NYR|0.74|64%|29%