Corsi has been taking a beating in Edmonton because the team sucks. Like any stat, it requires context and it can't just be viewed by itself.
For those who don't know, a Corsi event happens when a there's a shot that is stopped, blocked, misses the net or goes into the net at even strength. If you've got more Corsi events, it typically means that you spent more time in the other team's end, which is why we're interested in it.
However, teams go into a defensive shell when they are leading in games, which means that they don't press as hard to get into the offensive zone. That shows up in their Corsi - and it's as true in Edmonton as anywhere else. Last season, all but four teams gave up more shot attempts than they generated while leading. That's what we call score effects.
MARCELLUS WALLACE SCORE EFFECTS LOOKS LIKE
That's a visualization of the Corsi battle from the game against Chicago - you remember, the game where the Oilers got destroyed. This image shows the Oilers winning the Corsi battle (the Oilers are the blue line). At the end of the first period it was 3-0, Chicago eased off the gas pedal even though they scored four more goals, and on paper the Oilers' Corsi is improved.
The most common game state for the Oilers this year has been trailing by at least a goal. They're getting 53.6% of the shot attempts while trailing, but that's still 21st in the league. To try to compensate for score effects, I removed the Oilers' Corsi when they're trailing and found that they're sitting at 48.9%. Betterish than last year, but still not good. And there's another problem.
The Oilers haven't led often this season, but when they have the lead they get only 40.7% of the shot attempts, which is really bad - 27th in the league, in fact. Combine that with the bad goaltending they've received, and the Oilers are giving up more 5x5 goals per 60 while leading than all but three teams.
So either the Oilers are taking it easy on other teams while they have the lead, or they're not capable of coping with the push back, or both.
There are some encouraging signs, not least of which is that the Oilers are winning the even strength possession battle while tied this season. But the special teams and goaltending have been so bad that the positives are easily overwhelmed. The special teams dip and the team taking their feet off the gas while leading both strike me as being related to coaching, but I can't say for sure.
If the Oilers had average goaltending we'd be looking at a couple more wins, but the goalies would have to steal a game or two given the team's results with the lead.