Hivemind
We're Touched
There aren't any great metrics for evaluating individual performance as a penalty killer (or powerplay presence, for that matter), and I'm not aware of many studies regarding this area. Inspired by the premises in this thread, I decided to see how well various possession and non-possession events stand up to PK% for teams in 2013-14. For now, this is operating under the assumption that PK% is a good metric to evaluate a penalty killing unit. It's not perfect, but it's still likely the best we have given the goal of surviving a penalty without surrendering a goal trumps all else when it comes to killing penalties.
Predictably, GA/2 stacks up rather well with PK%. No surprises there.
This is where things start to get interesting. Shots Against/2 has a pretty darn weak correlation with actually killing penalties. While preventing shots as a whole is a good idea, there are some poor PK units that don't give up a ton of shots.
Corsi-event Against/2 fairs even worse than SA/2, and has the weakest correlation of any metric. So weak that it doesn't seem particularly useful at all.
Fenwick-event Against/2 does slightly better than Corsi. All things considered, this makes sense. Possession metric followers tend not to favor blocked shots not because it's a bad idea to block shots, but rather because high blocked shot totals mean the other team has control of the puck more. Given that it's pretty much assumed that the team on the powerplay is going to have the vast majority of possession, blocked shots are obviously a positive factor to killing penalties. Still, the FA/2 has a pretty weak correlation to PK%, and is worse than SA/2 (potentially related: the impact of goalies on missed shots).
Perhaps most surprising is how weak the correlation between sv% and PK% is. Based on shot metrics doing poorly, I was assuming that scoring chance quality would have to be the primary mover here, and that sv% could play out that hypothesis. While it certainly has a substantially larger correlation than anything aside of GA/2, it's nothing to write home about.
All this is pretty quick and dirty (I would have used more than one year's data if I had more time or it was quicker to combine the sources I needed), but was more intended to get the discussion rolling. What metrics are actually useful for measuring a penalty killing unit and individual penalty killers? How can they be improved?
Predictably, GA/2 stacks up rather well with PK%. No surprises there.
This is where things start to get interesting. Shots Against/2 has a pretty darn weak correlation with actually killing penalties. While preventing shots as a whole is a good idea, there are some poor PK units that don't give up a ton of shots.
Corsi-event Against/2 fairs even worse than SA/2, and has the weakest correlation of any metric. So weak that it doesn't seem particularly useful at all.
Fenwick-event Against/2 does slightly better than Corsi. All things considered, this makes sense. Possession metric followers tend not to favor blocked shots not because it's a bad idea to block shots, but rather because high blocked shot totals mean the other team has control of the puck more. Given that it's pretty much assumed that the team on the powerplay is going to have the vast majority of possession, blocked shots are obviously a positive factor to killing penalties. Still, the FA/2 has a pretty weak correlation to PK%, and is worse than SA/2 (potentially related: the impact of goalies on missed shots).
Perhaps most surprising is how weak the correlation between sv% and PK% is. Based on shot metrics doing poorly, I was assuming that scoring chance quality would have to be the primary mover here, and that sv% could play out that hypothesis. While it certainly has a substantially larger correlation than anything aside of GA/2, it's nothing to write home about.
All this is pretty quick and dirty (I would have used more than one year's data if I had more time or it was quicker to combine the sources I needed), but was more intended to get the discussion rolling. What metrics are actually useful for measuring a penalty killing unit and individual penalty killers? How can they be improved?
