Total Hockey Rating (THoR) results through 04/14/13By Michael Schuckers | April 19th, 2013 | Category: Empirical Sports Blog, Hockey, MIT SSAC, Uncategorized
The THoR page (http://www.statsportsconsulting.com/thor) has the latest set of Even Strength ratings for the top 150 players. I’ll give some commentary below. Since MIT Sloan, we have added rink effects for each rink to the rink effects for shots and a score effect when the score has a differential of 2 or more. The former aims to reduce bias in recording of RTSS events while the latter is indicative of changes of style of play according to the score. We got some good feedback at the MIT Sloan Sports Analytics Conference and from the Hockey Blogosphere and we’ll continue to tweak THoR appropriately. We also now list players by their total contributions (THoR) rather than their average contribution (THoRStandard) as we did in the original paper.
The data used here is all Even Strength (5v5 and 4v4) data for the complete 2011-12 season and the 2013 season through games played through Sunday, April 14th, 2012.
The top players for total contribution are Kopitar( +4.68), E. Staal (+4.28), Toews (+3.73), Bergeron (+3.73) and Couture (+3.61). THoR is measured in wins over an average player in an 82-game season. Thus, we are saying here that Kopitar is worth more than 4 and a half wins to his team. Note that a replacement player is approximately 0.3 goals below an average player in THoR. The top D is reigning Norris Trophy winner Erik Karlsson(+3.16). Sidney Crosby is penalized in both the total contribution and average contribution of THoR by the amount of time that he has during both seasons. Rounding out the top 10 are H. Sedin, Kunitz, the aforementioned Karlsson, Tavares and Getzlaf. Not a bad group.
The THoRStandard which is average contribution per play on the ice is topped by Steen (+4.87), Hornqvist (+4.60), Kennedy (+4.54), Toews (+4.52) and Clarkson (+4.44). It was this ordering that caused a ruckus with the original THoR but the model despite the changes listed above and the swapping out of the 2010-11 season for the 2013 season still thinks that good things happen when Steen and Kennedy are on the ice relative to what would be expected. (At least we’re getting consistent results.)
One criticism of THoR from Scott Cullen at TSN can be found here and it is the fact that THoR ignores scoring rate, the rate of shots by a given player that are goals. He validly points out that shots from Steven Stamkos are more likely to go in than shots by Tyler Kennedy. True. However, we know that shooting rates fluctuate a good deal over short periods like over a season. Further, we are not just counting shots by Stamkos and Kennedy in their value but the shots both taken by their teammates and opponents when they are on the ice. We’ll continue to assess this further and potentially tweak THoR. But when we tested this idea in the past it lead to much greater fluctuation in estimated player value.