Doctor No
Registered User
Thanks to those who helped me figure out my problems in the other thread. I'm starting this thread to place things that I discover about special teams-adjusted goaltending statistics.
A lot of people tout even-strength save percentage as the gold standard for measuring netminders in a vacuum. I agree with this to a point; the sample size is there and the data are more homogeneous. However, that penalizes goaltenders who do well in the other situations.
I instead prefer to measure how well a goaltender did, given the number of shots that they faced in each situation (ES, PP, SH), compared to the league average goaltender in those situations (those of you who have been annoyed by me for awhile could probably have guessed this).
For instance, Tuukka Rask of the Bruins allowed 115 goals in the 2013-14 season. Leaguewide, the average save percentages were 0.921 (vs. even strength), 0.878 (vs. power play), and 0.895 (vs. shorthanded). Rask faced 1359 even-strength shots, 251 power-play shots, and 31 short-handed shots, so we would expect him to allow: 1359*(1-0.921) + 251*(1-0.878) + 31*(1-0.895) = 140.7 goals.
In other words, controlling for manpower situations, Rask prevented 25.7 goals beyond what an average goaltender would have prevented.
Without controlling for manpower situations (just straight leaguewide save percentage), Rask prevented 27.0 goals beyond what an average goaltender would have prevented.
Therefore, the Bruins' manpower situations made Rask look about 1.3 goals better than he actually was. Is 1.3 goals a lot? How does Rask compare to other goaltenders in this regard?
A lot of people tout even-strength save percentage as the gold standard for measuring netminders in a vacuum. I agree with this to a point; the sample size is there and the data are more homogeneous. However, that penalizes goaltenders who do well in the other situations.
I instead prefer to measure how well a goaltender did, given the number of shots that they faced in each situation (ES, PP, SH), compared to the league average goaltender in those situations (those of you who have been annoyed by me for awhile could probably have guessed this).
For instance, Tuukka Rask of the Bruins allowed 115 goals in the 2013-14 season. Leaguewide, the average save percentages were 0.921 (vs. even strength), 0.878 (vs. power play), and 0.895 (vs. shorthanded). Rask faced 1359 even-strength shots, 251 power-play shots, and 31 short-handed shots, so we would expect him to allow: 1359*(1-0.921) + 251*(1-0.878) + 31*(1-0.895) = 140.7 goals.
In other words, controlling for manpower situations, Rask prevented 25.7 goals beyond what an average goaltender would have prevented.
Without controlling for manpower situations (just straight leaguewide save percentage), Rask prevented 27.0 goals beyond what an average goaltender would have prevented.
Therefore, the Bruins' manpower situations made Rask look about 1.3 goals better than he actually was. Is 1.3 goals a lot? How does Rask compare to other goaltenders in this regard?