Gabe Desjardins at Behind the Net has had a strong summer, posting a number of interesting items. There's a couple of them that I want to highlight in case anyone hasn't seen them and since they might lead to some good discussion.
One of them is his look at Minnesota's shot quality against. He illustrates the shot locations graphically, and also presents quotes from the Wild's director of hockey operations that show that according to the team's own evaluators they give up less dangerous chances than most teams do. This speaks directly to one of the counterarguments by Vic Ferrari (quickly paraphrased: "Why would the Wild pay Niklas Backstrom $6 million a year if we know they track scoring chances and other things and since they seem to know what they are doing?"). I agree that the Wild seem to know what they are doing, but Desjardins' quotes show that they seem to be aware of shot quality effects as well.
Desjardins also recently posted shot quality numbers for various coaches. Not surprisingly, Lemaire and Hitchcock show up at the top of the list, while someone like Quenneville, who I've identified before as a coach who apparently has a negative save percentage effects on his goalies by using a before/after analysis, shows up near the bottom. The list seemed to have a pretty close similarity with the subjective perception. That suggests there is something real behind the numbers. In fact, this makes it look like coaches might be quite significant in terms of a team's defensive system. If so, that could be one of the reasons why I found little difference between goalies who switched teams. A goalie playing on the same team with a new coach could be in a environment that is just as dissimilar to the previous year as if he was traded to another team.
There was also this post by James Mirtle where he looked at overall team save percentages for the last 10 years and post-lockout. Minnesota was .005 clear of the field in both periods. The case can certainly be made that Minnesota had good goaltending, but I think it is pretty clear they did not have goaltending that was that much better than the rest of the league. Part of this figure is related to power plays against, of course, and as a disciplined team Minnesota has an advantage in this regard.
I think there's enough good evidence to suggest that Minnesota had a significant shot quality effect under Lemaire. That doesn't mean that Backstrom, Roloson, et al are mediocre goalies who lucked their way to the top, just that they got some help on the way. Strong goaltending was also a contributing factor to the Wild's stellar defensive record over the last decade. It will be interesting to see how Minnesota plays post-Lemaire, and whether Backstrom's numbers will continue to be very good.
In the EV shot quality debate, I'm currently on the side that says that for most of the population it doesn't appear to be a significant variable but that there are a few outliers at both ends of the scale. I'd guess that there are something like 6-8 teams with shot quality effects that are big enough to worry about, either positive or negative.