Genuine question: So what is the proper evaluation tool?
I don't take corsi as the gospel either, so I'm curious how we quantify value from a defensive line.
This is a very good question Bench. It really is. Because there are issues with some of the ways we have been doing this:
1) If our 4th line is used at the end of games more often, and thus get empty net goals more often... this will skew their +/- Values.
2) Corsi/Fenwick measure shot attempts, but if our defensive line is allowing more "perimeter / non-dangerous" shots .... who cares?
We really need to know about scoring chances. Or shots from a certain area (high scoring area).
I would say these are my ways i would "evaluate" the 4th line
1) Straight up Goals For and Goals Against over time on ice. Or G/60; GA/60. BUT this would have to be at even strength, and also when at least 2/3rds of that line is on the ice. Not Glendenning filling in on the 3rd line etc. Basically we need someone to ACTUALLY COUNT?! how many goals are scored against our 4th line. (Not just the players on the ice)
Basically this:
2) I would like to see NOT how many shots they give up. But how many SCORING CHANCES our 4th line allows. Can this be counted??
3) I think Penalties drawn vs Penalties taken should be accounted for here. If we have a strong PP and our 4th line draws penalties... That helps us a lot!! If they take penalties and we get scored on...They might not be on the ice, but if they are in the box, its still partially their fault. So i dont know the results of this analysis, but penalties could be a big factor in 4th line effectiveness
These 3 measurements would tell us a lot more than "Corsi" or "+/-"