INTRODUCTION TO ThOR
(2013)
THoR is a two-way player rating that accounts for the all of the on-ice action events when a players is on the ice as well as their linemates (quality of teammates, QoT), their opponents(quality of competition, QoC), the current score of the game(Score Effects), and where their shift starts(Zone Starts).
Each event is assessed a value according to the chance that it leads to a goal. THoR uses a statistical model to determine the value of each player’s contribution to the overall outcomes that occur while they are on the ice.
THoR ralings are now wins above replacement (WAR) relative to position
THE CASE FOR THOR
THoR rates players by taking the probabilities of a subsequent goal for every event for which they are on the ice and accounting for who they played with, who they played against, where their shift started, the score of the game as well as whether or not they were at home. In doing so we attempt to isolate the impact of individual players.
THoR has roughly the same validity as Corsi and Fenwick but it is considerably more reliable. That is, THoR’s performance is highly correlated from year to year and, hence, more useful for predicting future performance.
The outcome metric for THoR is a value assigned to each play in the play by play files based upon the historical chance that it leads to a goal. THoR has build-in components to the model for dealing with home ice, score effects, rink effects, Quality of Teammates, Quality of Competition and Zone Starts.
EVALUATING THOR
Part I of that case shows that there is high year to year correlation between THoR Values meaning that THoR values are more likely to predict future THoR values. THoR has a year to year correlation of about 0.65 which is considerably higher than CorsiRel.
EVALUATING THOR II
Part II furthers the exploration of THoR by looking at how well THoR is associated with winning a game in the NHL. The response that THoR uses is in the neighborhood of Corsi and Fenwick in this regard though it is slightly less than both.
EVALUATING THOR III
Part III looks at the yearly THoR values for some specific players to give a sense for how THoR performs.
Comentarios