The first thing Jim Corsi wants the world to know? He didn’t invent the Corsi stat.

If that is a mystery to you, maybe you don’t know who Corsi is or what the stat named after him represents. If so, you haven’t been paying attention to the statistics revolution in the NHL that has made the last two months hockey’s summer of analytics.

Throughout the NHL, teams like the Maple Leafs, Devils, Penguins and Oilers have been gobbling up executives and statisticians who can walk them through what the blogosphere has been promoting for years — what some call analytics, or advanced statistics.

It’s growing social-media-powered movement with a fanatical following that believes there are means to measure a hockey player’s contribution to a team beyond the obvious stats of goals, assists and ice time.

And it all started with Corsi, hired this summer as goalie coach of the St. Louis Blues; he was previously with the Buffalo Sabres. He might otherwise be known as the WHA goalie who got a cup of coffee in the NHL with the Edmonton Oilers and, though born in Montreal, played on Italy’s national team.

But the stat named after him is his legacy.

“I’m humbled and happy because it gives coaches and fans and some reporters a way to try to address what a player’s contribution is to a game,” said Corsi, in an interview with thestar.com.

An outside-the-box thinker, Corsi was trying to measure just how busy his goalies were in a game. He didn’t believe the simple shots-against total — usually around 30 a game — was totally reflective of just how busy a goalie was. And since it’s up to the goalie coach to ensure the goalie is in shape, it was up to Corsi to find out how much workout time goalies needed between games.

So he added all shots and shot attempts, including ones that went wide, and ones that were blocked, figuring a goalie had to be in position or moving around regardless. He reasoned the shot total was more in the region of 50 to 70.

“I was doing work on how much work a goalie does,” Corsi said. “Another fellow took my stats and started applying it to players to find out what their contribution was overall, on both sides of the puck, and voila, the Corsi stat came out.”

That was around the lost season of 2004-05 and fans had time on their hands. Those with spreadsheets and ideas put their time to good use.

The bloggers who most often gets the credit are Tim Barnes, who formerly blogged anonymously — and more famously — as under the pseudonym “Vic Ferrari,” as well as California engineer Gabriel Desjardins, who runs Behindthenet.ca END

Barnes came up with many of the ideas behind hockey’s analytics while Desjardin’s website made them accessible.

Their ideas took root. Really intense fans were into crowd-sourcing their ideas in chatrooms and, later, on Twitter. These fans were unsatisfied with the NHL’s plus-minus stat, in large part because they believed goals were akin to random events.

There are more shots and shot attempts in a game than goals, meaning the larger sample size of Corsi events is more reflective of a player’s performance than whether a player is on the ice for an unlucky bounce.

By measuring the various shots in 5-on-5 situations — like plus-minus — it puts all players on a level playing field. The stars don’t get the advantage that power plays give them. The grinders aren’t hurt by their time killing penalties. They can be measured with various linemates and against strong or weak opposition.

At the same time, the blogosphere was trying to find out what teams were best at puck possession. The NHL dropped time of possession as a stat in 2002. So bloggers turned to Corsi as its proxy, figuring if one team shot the puck more than the other team, it meant one team controlled the puck more than the other team.

The blogosphere realized that teams with good Corsi numbers typically went very deep in the playoffs. They told anyone who would listen — and, in the beginning, few did — that a good Corsi rating was a predictor of what was to come.

Look no further than the 2013-14 Maple Leafs. As the wins piled up through the first 60 games despite routinely being outshot, the analytics crowd warned it was a mirage based on luck since the team’s Corsi rating was nearing record lows. When the team collapsed in the final quarter of the season, the analytics crowd said the numbers were merely catching up.

It has taken 10 years and countless Twitter fights for hockey’s analytics to go mainstream, thanks to the Maple Leafs and their collapse and off-season changes.

“Last year was the year people were able to predict things for the Leafs,” said Gabriel. “That gave all that analysis credibility. Then the Leafs made a decision to bring someone in and were quite public about it.

“That clears the way for every other team to be public about it.”

The Leafs hired Kyle Dubas as assistant GM, a 28-year-old born with hockey in his blood who has learned to at least listen to what the numbers are telling him.

They weren’t alone. The Oilers hired blogger Tyler Dellow, whose website mchockey79.com was among the leading analytics sites and is now shut down.

Earlier, the Devils had hired Sunny Mehta, a former pro poker player who turned his attention to analytics.

Wings coach Mike Babcock wants to learn more about it.

Loading... Loading... Loading... Loading... Loading... Loading...

Others had long been into it but were secretive about it, including Pittsburgh, Chicago and Los Angeles.

“I’m definitely pleased and surprised how it’s taken off in the last while,” said Corsi. “Everybody has started to understand there is more to the game than a haphazard slapping the puck around.”

In truth, teams have been dabbling in all kinds of stats, looking for that edge, for years. In the 1970s, legendary coach Roger Neilson had his own plus-minus stat based – subjectively – on who he thought deserved credit or blame for each goal. Dubbed Captain Video at the time, he went through every scoring play.

Former Leafs coach Ron Wilson was big on analyzing the game in a stats-based way. He looked mainly at scoring chances, a subjective look at the action around the net, and where they came from. He figured if his team out-chanced the opposition on a regular basis, the wins would come. Scoring chances were typically around 10 per team per game.

But the stats available have simply exploded. There’s Fenwick, a variation on Corsi in that it doesn’t include blocked shots. It’s named after its inventor, Flames blogger Matt Fenwick.

Then there are ways to measure Corsi and Fenwick based on linemates, the strength of opposition and what the score is in the game.

They are not always user-friendly. Unlike baseball, which went through its statistics revolution 20 years ago, hockey’s stats are not self evident. Baseball has WHIP (walks and hits per innings pitched) and OPS (On-base percentage and slugging percentage) and WAR (wins above replacement) which have joined the mainstream conversation in part because they don’t need to be explained.

Hockey has stats like has PDO, which doesn’t really stand for anything but adds shooting percentage and save percentage in an effort to define a team’s luck, and CF%rel, which stands for “Corsi for percentage relative to team's CF% with player not on ice.” Got that?

Some sites, like extraskater.com, thankfully, provide a glossary.

Corsi, the goalie coach, not the stat, is still on the leading edge of his profession. Last year, he put heart monitors on his goalies in exhibition games to measure their energy levels and calorie expenditure.

He believes the stats community and the teams that embrace them are on the right track.

“The beauty of it is it can open up a debate and can instruct,” said Corsi. “Our game, compared to other games, is so fast and reactionary, yet it is still programmed.

“There are routes. There are things to be done. I’d like to think you could evolve to another level and try to combine somehow the ability for a player to keep the puck from the other team.”

But Corsi also offered a subtle if familiar warning.

“I tell anyone who is willing to listen that statistics can be like a lamp post,” he said.

“You can use it to lean on or you can use it to illuminate. You’ve really got to be careful with all the information we’re getting.”

Read more about: