Based on his Corsi Stats, right-winger Teddy Purcell was a good signing by the Tampa Bay Lightning.
Haven’t heard of “Corsi Stats”? You’re not alone.
The NHL isn’t known as a statistically progressive organization. It often lags behind other major sports leagues when it comes to analytical number-crunching.
But new categories of statistics are gaining popularity and these state-of-the-art numbers are shining light into the dim corners of one of the world’s fastest and most complex games.
Corsi Stats – The NHL’s New Numbers
With the recent release of the film Moneyball, sports fans have been given a dramatic reminder of the power of statistical analysis in professional sport. When placed alongside the more stately sports, like baseball or football, hockey’s statistics can appear crude and underdeveloped.
But there are rational arguments why hockey is a difficult sport to quantify statistically.
Some sports revolve around discreet plays with specific starts and stops to the action. And in the case of baseball, one-on-one battles are often the focus of the action, which makes the compilation of statistics relatively easy.
Hockey, by contrast, has many more simultaneously moving parts, and there are few breaks in the action. It was once described by Toronto-based radio personality Bob McCown as “one long broken play during which players must consonantly adapt.”
Isolating individual player’s efforts from background clutter is very difficult.
But some observers and insiders are investing the time and effort to fight through the clutter, and their work has given hockey a bevy of new statistics.
These new stats are finding new ways beyond simple point- or penalty-based numbers to pinpoint players contributions, and NHL teams are taking notice.
“I’ve seen people use Corsi [Numbers] to make trades. I’ll put it that way.” Gabriel Desjardins from behindthenet.ca
The Use of Corsi Stats and Advanced Numbers
The Globe and Mail recently ran a series of stories investigating the use of statistics in the NHL. In one of those, Gabriel Desjardins, whose statistical analysis appears at behindthenet.ca, was profiled. According to the Globe, Desjardins commands up to $200 an hour from NHL teams to conduct statistical analysis. And are the new numbers affecting the league? “I’ve seen people use Corsi [Numbers] to make trades,” Desjardins said. “I’ll put it that way.”
As described by arcticicehockey.com, a Corsi Number is “the shot differential while a player was on the ice. This includes not just goals and shots on goal, but also shots that miss the net, and in some formulations, blocked shots. In other words, it’s the differential in the total number of shots directed at the net.”
The metric was allegedly created by former Buffalo Sabres goaltending coach, Jim Corsi, and directly speaks to a team’s ability to control the puck.
Arctic Ice Hockey argues that a Corsi Number “a better indicator of a team’s play than goals for and against, which are highly-driven by factors outside of a team’s control. Shot volume is much more a function of a team’s ability, and a much better predictor of future performance than goal-scoring metrics – in other words, there is basically no such thing as a team that shoots efficiently, just teams that get a lot of shots on goal.”
Most often, people use relative Corsi stats, which takes into account a player’s on- and off-ice Corsi, to show how team’s do with and without the player, further isolating the player’s contributions.
In an NHL where teams like the Detroit Red Wings have made puck possession a fashionable way to achieve success, Corsi Numbers make a lot of sense.
A Look at Last Year’s Leaders
Here are the relative Corsi leaders for the 2010-11 regular season (who played a minimum of 50 games), in five-on-five situations. All statistics are courtesy of behindthenet.ca.
1. Mikhail Grabovski (TOR): 21.3
2. Dustin Byfuglien (WIN): 20.7
3. Clarke MacArthur (TOR): 19.3
4. Ryan Kesler (VAN): 18.2
5. Mason Raymond (VAN): 17.5
While seeing Ryan Kesler’s name atop a league statistical category is hardly novel, names like Mikhail Grabovski and Clarke MacArthur will surprise some. Although Maple Leaf fans know that both had career years last season.
And here are Tampa’s Corsi leaders when playing five-on-five (who played a minimum of 50 games).
1. Sean Bergenheim: 12.0
2. Victor Hedman: 8.4
3. Ryan Malone: 8.0
4. Dominic Moore: 6.9
5. Teddy Purcell: 6.3
The Lightning weren’t dominant with their Corsi Numbers last year, and they let their highest Corsi-acheiver, Sean Bergenheim depart over the offseason. Bergenheim was tied for 33rd in the league (for those who played a minimum of 50 games) last year, and Tampa only had three skaters amongst the player with the 100 best Corsi Numbers.
Some of the Lightning’s star players like Steven Stamkos with a 0.8 Corsi Number, or St. Louis with a -2.2, were in the bottom-half of the team’s 2010-11 Corsi Numbers.
Here are the five-on-five Corsi leaders during the 2010-11 playoffs (who played a minimum of five games).
1. Marc-Andre Bergeron (TB): 53.3
2. Claude Giroux (PHI): 30.6
3. Ryan Smyth (LA): 28.8
4. Chris Kunitz (PIT): 28.8
5. Nicklas Backstrom (WAS): 28.3
1. Marc-Andre Bergeron: 53.3
2. Steve Downie: 25.7
3. Sean Bergenheim: 20.5
4. Teddy Purcell: 17.0
5. Blair Jones: 12.8
Mirroring their post-season success, the Lightning’s playoff numbers were far better than their regular season results, with 31-year-old (as of Oct 13th) Marc-Andre Bergeron leading the league. Again, Bergenheim and Purcell both appear in Tampa’s top-five.
With Corsi measuring the difference between a team’s shots taken and shots allowed while a player is on the ice, it can shed light on who the key puck possession players are on a team, defining a player’s value to a degree that goes beyond just goals and assists
But in no way are Corsi Numbers exempt from the limitation that impacts all statistics – a player’s numbers are derived from the situations in which he is placed. Players who play in less demanding situations will have better numbers. Corsi Numbers are certainly not a silver bullet that bring perfect clarity to hockey.
What is clear, however, is that new statistical measures are helping to make the previous unmeasurable measurable, even if they still seem exotic to many fans.
What remains to be clarified is just how exotic they remain to teams like the Tampa Bay Lightning.
In the case of Teddy Purcell, it’s entirely possible the his Corsi Numbers helped earned him his new two-year, $4.73 million contract – especially once Bergenheim signed with the Lightning’s cross-state rivals, the Florida Panthers.
Brent’s hockey writing has appeared in a variety of online and print media, including the Yahoo! Sports NHL blog, Puck Daddy, and USA Today magazines. He shoots left.