What you see above are the even-strength shots-for locations for the near-indisputable top team of the last five seasons (Chicago Blackhawks) versus the near-indisputable worst team of the last five seasons. This is a sort of visual anti-shot quality argument, a demonstration of why, across these five seasons, the indisputable #1 team would shoot 9.9% while the indisputable #30 team would shoot 9.6%. Notice the horseshoe design, about where defensemen normally sit, then jump up into the play. Notice the dense cluster around the high slot. All teams make these plays, try to make them, the difference being some are better at possessing and moving the puck to make the shot. What’s the primary difference above? The amount of shots.
None of the above charting is possible without Greg Sinclair’s awesome site, Super Shot Search. Bookmark it, use it, love it.
Oh, hey, what if I was to look at the teams with the best and worst save percentage these last five years? Would they look different in even-strength shots-against? Well, let’s see, Toronto and Boston:
There is a difference here, I think. I mean, the initial difference are the numbers, Boston’s SV% (92.1%) versus Toronto’s (89.5%). Another difference is it seems the two charts maintain roughly the same shot distributions, but flip ends of the rink. Not much to dwell on there. One thing I will say, that could relate to the SV% discrepancy, is that it doesn’t appear that Toronto records many, if any, shots from right along the boards. Now, I don’t know if this is a recorder’s error or not; it seems to me it’s pretty hard to get a shot from right tight along the boards. Maybe one recorder does it based on where the body of the skater was located, I don’t know. Or…Toronto does allow shooters to come in a little tighter, and Boston owns the center ice a bit better. Could that explain a near-3% discrepancy? I don’t think so; we know Toronto’s had worse goaltending. But it might’ve “helped.”
Hockey Graphs 
Here’s my concern:
Perhaps over the long-term, with a wide variety of opponents, shot quality doesn’t matter. But in game-to-game iterations, it’s really hard to ignore.
The use of chances for/against among the uneducated has become argument for why a team “shouldn’t win/have won” as opposed to a predictive tool for why in the long run we shouldn’t expect a team to have an inordinate amount of success. If we continue to use Corsi as a be-all end-all stat in game-by-game iterations, we’re ignoring that on any given night a team can get itself into objectively better positions than their opponents, and that can help pave over the difference in the number of chances.
Not saying that’s being ignored (or even addressed) here, but the shot quality camp trying to poke holes in the Corsi methodology seems to moreso be coming at it from that perspective.
Thoughts?
I think there’s room for both arguments; I mean, they’re not necessarily disagreeing with each other, right? The problem is when you go from “The reason Team A lost that game is they allowed Team B to break through for quality chances” to “The reason Team A is bad is because they routinely allow opposing teams to break through for quality chances.”
Another case in-point is the Dustin Byfuglien turnover argument. Yes, in certain games, Dustin Byfuglien’s turnovers lead to goals. But it comes out in the wash of a season’s data, wherein overall he’s a plus player and it’s likely that the turnovers stick out because he also carries the puck often.
That being said, nobody I know working in this stuff would say Corsi is a be-all, end-all stat. In fact, I rarely use Corsi except for mid-season to end-of-season projections.