Jim Corsi: The man behind Corsi numbers


The hockey world is ages behind “Moneyball” philosophy and Sabermetrics, just to name a few buzzwords associated with the innovative stats championed by baseball writers and stats gurus for years. That isn’t to say that hockey bloggers/writers/fans/front office people are completely turning a blind eye to analysis that goes deeper than goals, assists and plus/minuses, though.

One of the most well-known “new” stats is the Corsi Number, named after Buffalo Sabres goalie coach Jim Corsi (he’s the guy in that photo who’s either short … or maybe standing next to Tyler Myers). To explain the stat (a bit too) simply: it’s basically an alternative to plus/minus in which shots replace goals. Here’s a more detailed description from David Staples’ great story about Corsi (the man and the stat).

Corsi is a plus/minus stat that measures shots directed at net. For example, if the Edmonton Oilers direct 30 shots at even strength at the Calgary Flames’ net in a game, while the Flames direct 45 shots at the Oilers’ net, the Oilers have a Corsi of -15 for the game. People who put a lot of faith in Corsi plus/minus numbers argue that you even if a team loses a stretch of games, but if that team has a strong Corsi plus/minus in each game, it’s an indication that the team really isn’t so bad, that it’s moving the puck to the right end of the ice, that it has territorial dominance, and that the goals will soon come.

This team Corsi number is also broken down and applied to individual players. For example, if Sheldon Souray is out on the ice for 10 shots directed at the Flames’ net, while the Flames direct 15 shots at the Oilers’ net while Souray is on the ice, he’s said to have a Corsi plus/minus of -5.

It’s a fascinating story that is definitely worth the read. I’ll leave you with the stat’s origin story, from Corsi himself.

The traditional way of measuring a goalie’s work load was to look at the number of shots against the goalie faced in a game. But having played goalie himself, Corsi didn’t trust that basic indicator so much. “When I played, I’d finish a game with about 25 shots on goal and I was really tired. I was really very, very tired,” he says.

“When you look at 20 or 25 shots, you say, Well, it’s a light game.’ But if you look at a game, an (attacker) comes down the right side, he’s got the puck, and he turns up the boards, towards the wall, the goalie is not standing on his heels going, ‘Oh, you know, whatever.’ He’s going to bear down, tense up, prepare that this is going to end up as a shot. Now as (the attacker) turns, he (the goalie) has still got to be engaged and wait for the next play.

“You get a 25-shot game, but with all the blocked shots and the increase in blocked shots and the tightness of the defensive zone coverage, the activity of the goalie could almost be like 75 to 100 actions at the net.”

To get a better sense of how much work his goalies faced, Corsi started to use the NHL’s data that tracks missed shots, blocked shots and shots on goal. He added all these together to come up with a goalie’s so-called Corsi number for a night of work. “It’s really just a number that I’ve used for goaltenders to hone in on their fitness and how much activity is actually going on with respect to goaltending.”

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    Stepan to miss 4-6 weeks with broken ribs

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    Derek Stepan is out 4-6 weeks with broken ribs, the New York Rangers announced today.

    Stepan was hurt Friday on a controversial hit by Boston’s Matt Beleskey. The Bruins’ forward did not receive any supplemental discipline for the check, despite admitting it was “maybe…a little bit late.”

    It’s a big loss for the Rangers, who suddenly find themselves on a three-game losing streak. Considering the timeline, New York could be without one of its top centers for 12-18 games, give or take.

    The Rangers host Carolina tonight.

    Related: Yep, Alain Vigneault went there — ‘I remember Aaron Rome in this building’

    Price to miss minimum six weeks, so no Winter Classic for him

    Carey Price,
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    Carey Price will miss a minimum of six weeks with a lower-body injury, the Montreal Canadiens announced today.

    That means Price will miss the Winter Classic against the Bruins on New Year’s Day. The 30-year-old goalie has only appeared in 12 games this season.

    On the bright side, the reigning Hart Trophy winner will not require surgery. And considering the Habs have already built up a 13-point playoff cushion in the standings, well, if something like this were going to happen during the season, now is as good a time as any.

    Related: The latest on Price’s injury

    Report: Jets offered Byfuglien for Hamonic, Isles said no

    Dustin Byfuglien

    If Travis Hamonic could choose one team to be traded to, he’d probably choose Winnipeg. The 25-year-old Islanders defenseman wants to be closer to his family, and his family is from Manitoba. Hamonic already owns a condo in Winnipeg.

    So far, though, the Jets and Islanders haven’t been able to work out a deal. The Jets have three right-shot defensemen in Dustin Byfuglien, Jacob Trouba, and Tyler Myers who could, theoretically, be swapped for Hamonic, also a right shot.

    “I think the Islanders were offered Byfuglien and they said no,” Sportsnet’s Elliotte Friedman said this morning on Sportsnet 960 (audio), per Today’s Slapshot. “And I understand why, because Byfuglien’s got no term left.

    “I think they’d love to have Trouba, but the Jets aren’t really there to do it. Myers, if it’s happened – I can’t say for sure it has or hasn’t – I’m not sure that’s the deal either team really wants to make, to be perfectly honest.”

    Byfuglien is a pending unrestricted free agent who’s expected to cash in big-time on his next deal. The 30-year-old may not be the most disciplined player, but at his best, he’s an absolute force on the back end.

    That the Isles reportedly said no to Byfuglien shouldn’t really come as a surprise, given his contract uncertainty. However, it does make one wonder about his future in Winnipeg. Remember that the salary cap is not expected to go up by much, and the Jets have another pending UFA in captain Andrew Ladd, plus a couple of key RFAs in Trouba and Mark Scheifele.

    While it’s never easy to tell what GM Kevin Cheveldayoff is thinking, the big question with Byfuglien and the Jets may end up being when, not if, they part ways. Will it be after the season or before the Feb. 29 trade deadline?

    Preds still haven’t found their scoring touch

    Mike Fisher
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    The Nashville Predators got off to a relatively good start this season, but something seems to have happened to their offense over the last six games.

    Prior to Nov. 20, the Preds had only been shut out once in their first 17 games. Since then, they’ve been blanked three times and have just six goals in their last six contests.

    If you remove Mike Fisher from the equation, the numbers are even more dreadful.

    Fisher’s scored three of those six goals, while Filip Forsberg, Shea Weber, James Neal and Mike Ribeiro have none.

    After Saturday’s 4-1 loss to Buffalo , here’s what coach Peter Laviolette told the Tennessean: “I thought we could’ve had more gas, to be honest with you. The energy just wasn’t there; maybe the second period had something to do with that or the road trip, which was a long trip. I’m not making any excuses, but I think when we play at a higher tempo that’s when we’re at our best, and we had more to push in that area tonight.”

    The first game back home after a long road trip is typically a difficult one for most teams, so we’ll see how the Predators respond on Tuesday night when they host Arizona.