In a constant effort to provide as much context as possible to my data-generated player tracking system, I've looked into more traditional "advanced-stats" metrics.
Fenwick and Corsi numbers take a global picture of what occurs when a player is on the ice (shots attempted for and against), and uses those numbers to rate individual players. My system tracks individual player's puck-possession successes and failures (passes, dekes, puck-battles, etc) with a similar goal in mind.
Habs Eye on the Prize's Andrew Berkshire explains Corsi as follows:
Corsi - is a +/- statistic for a player/team that measures all shot attempts, including misses and blocked shots, directed for and against the team/player being measured per 60 minutes.
Andrew explains Corsi Relative Quality of Competition as follows:
Relative Corsi quality of competition - a measure of the average relative Corsi score of the opponents a player faces, weighted against the ice time played against each player
Silversevens.com explains the calculation for Corsi Relative Quality of Competition as follows:
Corsi Rel QoC is the weighted Relative Corsi Number of a player's opponents.For example, if a player plays 30% of the time against five players with a relative corsi of +1.5, 35% of the time against five players with a relative corsi number of +0.2, and 35% of the time against five players with a relative corsi number of -2.1 then:
Corsi Rel QoC = (0.3 * 5 * 1.5) + (0.35 * 5 * 0.2) + (0.35 * (5 * (-2.1)) = -1.075
The graph is a visual representation of each Montreal Canadiens player's even-strength risk/reward rating as calculated using my system, while the other bar is a visual representation of each player's ES risk/reward rating after including Corsi relative quality of competition into the calculation.
Even-strength risk/reward is a rating that determines how many more positive events than negative events a player produces per-minute of even-strength ice-time. Events used within this system include; puck-battles, loose-puck recoveries, passes, dekes, shots, blocked passes, blocked shots, dump-ins, dump-outs, and deflections. Each event is tracked as a success or failure.
In order for the calculation to work, and for the numbers to make sense, I've divided each Canadiens player's Corsi Rel QoC number by 5. Not only does this help minimize the impact on the original number, it also relates better to the reality of my system; Corsi uses team numbers while a player is on the ice. In orde to accomplish this it multiplies the value by 5 to represent the five skaters on the ice. My system tracks individual events taking place against individual players. As such, it does not need to by multiplied by 5.
The quality of competition numbers used in this calculation can be found here.
Raphael Diaz and Josh Gorges have faced the highest relative quality of competition among Montreal defensemen. As such, their even-strength risk/reward rating improved the most following the qualcomp adjustment. Other d-men with improved risk/reward ratings include PK Subban, and Andrei Markov. The drop in risk/reward rating (both adjusted and pre-adjusted) after Subban, Gorges, and Markov point to a need for another top-4 defenseman capable of matching the performances of the Habs top-3.Tomas Plekanec and Lars Eller have faced the toughest competition among Montreal centres. This is apparent in their adjusted risk/reward. Plekanec's adjusted rating is particularly impressive, and does a great job of relating the high qualcomp number 14 faces each game. This graph also does a good job of relating the struggles of David Desharnais; whose adjusted risk/reward rating last season was 1.40, but is barely 1.0 this season.
Among wingers, Michael Bournival and Max Pacioretty have the highest adjusted risk/reward ratings. Bournival's adjusted rating helps reinfoce how well he's been playing this season, while Pacioretty's displays the fact that number 67 has faced (far-and-away) the highest quality of competition among all Montreal players.
George Parros, Michael Blunden, and Rene Bourque have the lowest even-strength risk/reward rating both before and after the quality of competition adjustment. That said, Daniel Briere's risk/reward rating improves dramatically when qualcomp is incorporated into his rating.
Context is an important aspect of player evaluation. The inclusion of quality of competition numbers into the calculation of a player's risk/reward rating helps produce just that context.
