I just want to wrap up my fixation on Boudreau and offensive zone faceoff losses, which I’ve discussed (in order) here, here and here. It occurred to me that I should probably discuss the goals for/against.
Nobody who pays attention to Corsi cares about it for abstract reasons. They care about it because Corsi is tightly correlated with goals, there are way more Corsi events in a game than there are goals and goals are subject to considerable randomness. So when I’m talking about a player who I think helps Corsi, what I’m really saying is “I think this guy does things that will help his team outscore the opposition.”
As I’ve mentioned repeatedly, I’m a believer in breaking the game down into digestible pieces based on sensible criteria. One of the ways that I do this is by identifying the period of time following a faceoff in which there is an effect based on the location/outcome of the draw. I have a database that has all of the 5v5 faceoffs from 2007-13 and has classified all of the Corsi events based on whether there’s a faceoff influence. Here’s what the data shows us:
The relationship between Corsi% and GF% shows up again. The astute observer will note that teams winning offensive zone and neutral zone faceoffs don’t get quite the GF% that their Corsi% would suggest. I suspect that that’s tied to the defensive team being more likely to have five guys behind the puck when the shot is taken. It’s not a massive effect though – if someone offered you the chance to only take offensive zone faceoffs, all of which you’d win, you’d live with the fact that the GF% isn’t quite up to the Corsi%.
Anyway, Boudreau. Piling up Corsi% without getting goal difference is pointless. This is why stat guys just sort of stare blankly at people who say “What, you think guys should just shoot when they cross centre ice?” Stats guys don’t think you should fire from anywhere; they do think that you should do the things that lead to you having more opportunities to shoot the puck from the places people shoot the puck.
If the Corsi% that Boudreau-coached teams have piled up after losing offensive zone faceoffs has any value, it will show up in their GF%. Higher Corsi% should, over time, equal higher GF%. Does it check out?
Yep. What I find striking about this is how different the Ducks and Capitals are. Nobody would refer to the Capitals as a big, heavy team but you hear ad nauseum about what a big, heavy team the Ducks are. It doesn’t seem to matter – either team, Boudreau gets them to murder the opposition after they lose an OZ faceoff at 5v5 and turn it into goals.
At the risk of raising the ire of my good pal Sacamano, I don’t know how you could reasonably expect a coach who coaches 82 games a year against 29 different teams and has his own team to be responsible for as well to suss out who’s got the most effective tactics for him to steal without a back room running this sort of analysis. The fact that Boudreau’s been getting these kinds of results for years and it hasn’t been sussed out and either nullified or lifted by every other team in the NHL is amazing, right up until you consider that, without numbers, breaking the game into tiny pieces like this and comparing thirty teams is pretty much impossible.Email Tyler Dellow at firstname.lastname@example.org