Please have a look around!

If you have any questions, please see the *Glossary* section for explanations of the various metrics found on the site and the *References* section for background on the methods used.

We can be reached on Twitter – @EvolvingWild – for any and all discussion about the information found here.

Thanks,

Josh & Luke

Under Construction

Data acquired from NHL HTM source via Emmanuel Perry's Dry Scape R functions which can be found on his GitHub page

You can find us on Twitter @EvolvingWild

If you would like to help support the work we do, you can become a patron through our Patreon Page

Model | Version | Release Date |
---|---|---|

Expected Goals | 1.0 | 06/07/18 |

Statistical Plus-Minus / Goals Above Replacement (Skaters) | 1.1 | 09/04/18 |

Goals Above Replacement (Goalies) | 1.0 | 09/04/18 |

Regularized Adjusted Plus-Minus (Skaters) | 1.1 | 08/19/18 |

Regularized Adjusted Plus-Minus (Teams) | 1.1 | 09/04/18 |

Penalty Goals (Skaters & Goalies) | 1.0 | 07/04/18 |

Under Construction

© Evolving Hockey 2018. All Rights Reserved.

Goals Above Replacement & Statistical Plus Minus: RITSAC slides, Video. and [future writeup link]

Expected Goals Model: A New Expected Goal Model for Predicting Goals in the NHL (2018)

Relative to Teammate Method: Revisiting Relative Shot Metrics - Part 1 and Revisiting Relative Shot Metrics - Part 2

Relative to Teammate Score Adjustment: McCurdy, 2014: Better Way to Compute Score-Adjusted Fenwick

Corsica Hockey Glossary: Perry, 2016

Adjusted Plus-Minus for Basketball: Rosenbaum, 2004 and Ilardi & Barzilai, 2008

Reguarlized Adjusted Plus-Minus (RAPM) for Basketball: Sill, 2010

NHL Regularized Adjusted Plus-Minus based on Brian MacDonald's original work: first paper, second paper, and third paper

Additional shift-by-shift regression models for hockey:

Galamini Jr., 2017: HERO Charts (Old Version) – Frequently Asked Questions

Perry, 2018: Wins Above Replacement

Goalie Goals Above Replacement References:

Thomas, 2015: The Road to WAR, Part 10: Modern Goaltending and Shooting

Perry, 2018: Wins Above Replacement - The Shooting and Goaltending components of WAR…

__General Terms:__

Measure | Definition |
---|---|

GF | Goals For |

GA | Goals Against |

SF | Shots For (goals, shots on goal) |

SA | Shots Against (goals, shots on goal) |

FF | Fenwick For (goals, shots on goal, missed shots) |

FA | Fenwick Against (goals, shots on goal, missed shots) |

CF | Corsi For (goals, shots on goal, missed shots, blocked shots) |

CA | Corsi Against (goals, shots on goal, missed shots, blocked shots) |

xGF | Expected Goals For (total goal probability of all Fenwick shots) |

xGA | Expected Goals Against (total goal probability of all Fenwick shots) |

Strength State | Definition |
---|---|

EV | Even-Strength (5v5, 4v4, 3v3) |

PP | Powerplay (5v4, 5v3, 4v3) |

SH | Shorthanded (4v5, 3v5, 3v4) |

Measure | Definition |
---|---|

SD | Standard Deviation |

__Skater Stats - Standard:__

Metric | Definition |
---|---|

iSF | Total individual shots on goal |

iFF | Total individual fenwick shots on goal |

iCF | Total individual corsi shots on goal |

ixG | Total individual expected goals |

Sh_perc | Shooting Percentage: `G` / `iSF` |

F_Sh_perc | Fenwick Shooting Percentage: `G` / `iFF` |

xFSH_perc | Expected Fenwick Shooting Percentage: `ixG` / `iFF` |

iHF | Total invidiual hits for |

iHA | Total individual hits against |

GIVE | Total giveaways |

TAKE | Total takeaways |

iPENT2 | Total 2-minute minor penalties taken - includes offsetting penalties |

iPEND2 | Total 2-minute minor penalties drawn - includes offsetting penalties |

iPEND5 | Total 5-minute major penalties taken - includes offsetting penalties |

iPENT5 | Total 5-minute major penalties drawn - includes offsetting penalties |

FOW | Total faceoffs won |

FOL | Total faceoffs lost |

FO_diff | Faceoff differential: `FOW` - `FOL` |

TOI_GP | Time on ice per game played |

TOI_perc | Percentage of available team minutes played: `TOI` / `total team TOI` |

OZS | Offensive zone starts |

NZS | Neutral zone starts |

DZS | Defensive zone starts |

OZS_perc | Percentage of total zone starts in the offensive zone: `OZS` / (`OZS` + `NZS` + `DZS` ) |

DZS_perc | Percentage of total zone starts in the neutral zone: `NZS` / (`OZS` + `NZS` + `DZS` ) |

NZS_perc | Percentage of total zone starts in the defensive zone: `DZS` / (`OZS` + `NZS` + `DZS` ) |

ZS_rate | OZS / (OZS + DZS) |

__Goalie Stats - Standard:__

Metric | Definition |
---|---|

GA | Goals Against |

GA_ | Goals Against (fenwick shots without location data removed) |

SA | Shots On Goal Against |

FA | Fenwick Shots Against |

xGA | Expected Goals Against |

SV_perc | Save Percentage: 1 - (`GA` / `SA` ) |

FSV_perc | Fenwick Save Percentage: 1 - (`GA_` / `FA` ) |

xFSV_perv | Expected Fenwick Save Percentage: 1 - (`xGA` / `FA` ) |

d_FSV_perc | FSV_perc - xFSV_perc |

GSAA | Goals Saved Above Average: (`League SV_perc` * `SA` ) - `GA` |

GSAx | Goals Saved Above Expected: `xGA` - `GA_` |

__Penalty Goals:__

Metric | Definition |
---|---|

take_count | Total penalties taken that resulted in a change of strength state |

draw_count | Total penalties drawn that resulted in a change of strength state |

adj_take | Total raw goal value of `take_count` |

adj_draw | Total raw goal value of `draw_count` |

take_AA | Penalties Taken Goals Above Average (inverted, per position): `adj_take` centered around the positional mean |

draw_AA | Penalties Drawn Goals Above Average (per position): `adj_draw` centered around the positional mean |

pens | `take_AA` + `draw_AA` |

__Goals Above Average & Replacement (Skaters):__

Metric | Definition |
---|---|

EVO_AA | Even-Strength Offense Goals Above Average (per position) |

EVD_AA | Even-Strength Defense Goals Above Average (per position) |

PPO_AA | Powerplay Offense Goals Above Average (per position) |

SHD_AA | Shorthanded Defense Goals Above Average (per position) |

take_AA | Penalties Taken Goals Above Average (inverted, per position) |

draw_AA | Penalties Drawn Goals Above Average (per position) |

EV_GAR | Even-Strength Goals Above Replacement (Offense + Defense, per position) |

PP_GAR | Powerplay Offense Goals Above Replacement (per position) |

SH_GAR | Shorthanded Defense Goals Above Replacement (per position) |

Pens_GAR | Penalty Goals Above Replacement (Taken + Drawn,per position) |

__Replacement Level (Skaters):__

Metric | Definition |
---|---|

Even-Strength (EVO + EVD) | Aggregate rate below average of all skaters outside the top 13 F or top 7 D per team per season ('07-'18) |

Powerplay Offense | Aggregate rate below average of all skaters outside the top 11 skaters per team per season (per position, '07-'18) |

Shorthanded Defense | Aggregate rate below average of all skaters outside the top 11 skaters per team per season (per position, '07-'18) |

Penalties (Take + Draw) | Aggregate rate below average of all skaters outside the top 13 F or top 7 D per team per season (all situations, '07-'18) |

__Goals Above Average & Replacement Minimum TOI Thresholds (Skaters):__

Metric | Definition |
---|---|

Even-Strength (EVO + EVD) | 60 minutes |

Powerplay Offense | 25 minutes |

Shorthanded Defense | 25 minutes |

Penalties (Take + Draw) | None |

__Goals Above Average & Replacement (Goalies):__

Metric | Definition |
---|---|

GAA_per_fenwick | Goals Above Average per Fenwick Shot Against (the transformed coefficient from the regression. See below) |

FA | Total fenwick shots against |

GAA | Goals Above Average: `FA` * `GAA_per_fenwick` |

GAR | Goals Above Replacement: `GAA` + (`FA` * `0.007312411` ) // inverted replacement level GAA_per_fenwick |

WAR | `GAR` / `season goals per win` |

__Goals to Wins Conversion:__

Following the Pythagorean Expectation method (originally developed in baseball - explained here), we find the optimal x in the following equation:

- W% =
`GF`

^{x}/ (`GF`

^{x}+`GA`

^{x})

- W% =
This works out to a “pythagorean exponent” of ~2.1 (similar to prior work here and here). We use the following calculation per season to derive “goals per win”, which allows us convert skater and goalie GAR into WAR:

- Goals Per Win = (4 * League
`GF`

per Game) / 2.091

- Goals Per Win = (4 * League

__Methods:__

**Relative to teammate (rel_TM)**:

*player on-ice CF60 - weighted average of all teammates' on-ice CF60 (weighted by player TOI % with teammate)*- This calculation is used for all respective rel_TM measures (GF, xGA, etc.)

**Regularized Adjusted Plus-Minus (RAPM)**

Shift-level weighted ridge regression. The target variable is a per 60 rate (separate regressions are performed using GF60, CF60, and xGF60 as the target variable), the weights are the length of each shift (shift is defined as a period of play where no player substitutions occur), and the predictor variables are:

- all skaters - offense (dummy variable, 1 = on ice, 0 = not on ice)
- all skaters - defense (dummy variable, 1 = on ice, 0 = not on ice)
- all goalies - defense (dummy variable, 1 = on ice, 0 = not on ice). Only used in GF60 regression
- score state (7-level factor variable, home lead of -3 through +3)
- strength state (factor variable equal to the applicable strength states in the regression)
- offensive “zone start” (1 = shift included at least one faceoff in the offensive zone, 0 = no faceoff in offensive zone)
- defensive “zone start” (1 = shift included at least one faceoff in the defensive zone, 0 = no faceoff in defensive zone)
- back-to-back (1 = offensive team had one night of rest, 0 = offensive team had more than one night of rest)

- The skater ratings are the coefficients that result from the regression. These are interpreted as a skater's offensive and defensive contribution (per 60 minutes) to the league scoring rate (Goals, xG, or Corsi).

**Goalie GAR/WAR**

Fenwick shot-level regularized logistic regression. The target variable is 1 (Goal) or 0 (No Goal) and the predictor variables are:

- all shooters (dummy variable, 1 = skater took the shot, 0 = skater did not take the shot)
- all goalies (dummy variable, 1 = goalie facing the shot, 0 = goalie not facing the shot)
- expected goal value of the fenwick shot (probability between 0 and 1)
- strength state (8-level factor variable: 5v5, 4v4, 3v3, 5v4, 5v3, 4v3, Ev5, Ev4)
- shooter score state (3-level factor variable: shooter team is leading, tied, or trailing when shot was taken)
- shooter venue (home or away team)
- shooter position (forward or defenseman)
- back-to-back (home team / away team playing with < 2 nights of rest)

- The goalie coefficients that result from this regression are interpreted as each goalie's impact on the odds of a goal being scored. These coefficients are converted to probabilities and multiplied by the total fenwick shots each goalie faced to arrive at “Goals Above Average” (GAA).
- Goals Above Average is then converted to Goals Above Replacement (GAR) as such:
`GAA`

+ (`FA`

*`replacement level GAA per fenwick`

)

**Shooter GAR**

- The shooter coefficients from the regression described in the
*Goalie GAR/WAR*section. - The shooter coefficients that result from this regression are interpreted as each shooter's impact on the odds of a goal being scored. These coefficients are converted to probabilities and multiplied by the total fenwick shots each shooter took to arrive at “Goals Above Average” (GAA).
- Goals Above Average is then converted to Goals Above Replacement (GAR) as such (replacement level is set per forward and per defenseman using the same cutoff described in the
*Replacement Level (Skaters)*section):`GAA`

+ (`iFF`

*`replacement level GAA per fenwick`

)

**Table types**

- Rate: per 60 minutes of play, calculated as: (raw metric / TOI) * 60
- Impact: implied total, calculated as: (per 60 metric / 60) * TOI
- The relative to teammate and RAPM metrics are inherently per 60 rate stats - this is used to “convert” the rates into counting stats

**Score Adjustments**

All on-ice and relative to teammate metrics (EV, PP & SH - Skaters and Teams) are score adjusted using the method developed by Micah Blake McCurdy.

__Even-Strength__

*Goals:*

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 0.936 | 1.074 |

Tied | 0.948 | 1.058 |

Leading | 0.987 | 1.014 |

*Expected Goals:*

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 0.915 | 1.103 |

Tied | 0.951 | 1.055 |

Leading | 0.992 | 1.008 |

*Shots on Goal:*

Home Lead State | Home Weight | Away Weight |
---|---|---|

-3 or worse | 0.861 | 1.193 |

-2 | 0.892 | 1.137 |

-1 | 0.916 | 1.101 |

0 | 0.973 | 1.029 |

+1 | 1.036 | 0.967 |

+2 | 1.072 | 0.937 |

+3 or better | 1.103 | 0.915 |

*Fenwick Shots:*

Home Lead State | Home Weight | Away Weight |
---|---|---|

-3 or worse | 0.860 | 1.193 |

-2 | 0.885 | 1.150 |

-1 | 0.911 | 1.109 |

0 | 0.970 | 1.032 |

+1 | 1.036 | 0.966 |

+2 | 1.074 | 0.935 |

+3 or better | 1.109 | 0.911 |

*Corsi Shots:*

Home Lead State | Home Weight | Away Weight |
---|---|---|

-3 or worse | 0.844 | 1.227 |

-2 | 0.869 | 1.177 |

-1 | 0.900 | 1.124 |

0 | 0.971 | 1.031 |

+1 | 1.051 | 0.954 |

+2 | 1.100 | 0.917 |

+3 or better | 1.139 | 0.892 |

__Powerplay / Shorthanded ***__

*Goals:*

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 0.860 | 1.194 |

Tied | 0.928 | 1.084 |

Leading | 0.980 | 1.020 |

*Expected Goals:*

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 0.843 | 1.230 |

Tied | 0.915 | 1.102 |

Leading | 0.995 | 1.005 |

*Shots on Goal:*

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 0.841 | 1.234 |

Tied | 0.930 | 1.082 |

Leading | 1.041 | 0.962 |

*Fenwick Shots:*

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 0.838 | 1.239 |

Tied | 0.926 | 1.086 |

Leading | 1.031 | 0.971 |

*Corsi Shots:*

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 0.837 | 1.241 |

Tied | 0.930 | 1.082 |

Leading | 1.045 | 0.959 |

*** Home & Away weights are reversed for shorthanded goals, xG, shots, fenwick, and corsi against

__Penalty Goals__

Home Score State | Home Weight | Away Weight |
---|---|---|

Trailing | 1.175 | 0.870 |

Tied | 1.049 | 0.956 |

Leading | 0.964 | 1.039 |

© Evolving Hockey 2018. All Rights Reserved.

Loading...