Advanced Stats Man Corsi Hired As Blues Goaltending Coach


Saku Koivu, Corsi Relative Quality of Competition, 2011-14
Jim Corsi’s statistical analysis are used by hockey analysts in evaluating shot quality, among others.

Stats guru Corsi brings successes in the name of Hasek, Miller

Jim Corsi has been hired as the Blues’ goalie coach. Corsi, who had great success with legend Dominik Hasek and recent Blue Ryan Miller, will take over from Corey Hirsch. Corsi is probably better known as the name behind a system of advanced statistical analysis, evaluating primarily scoring chance and shot quality metrics. Corsi, a minor-league and international goalie himself, began to evaluate what was happening at both ends of the rink, a curiosity initially spurred on through his playing days. By examining shot and scoring chance quality rather than simply looking at shots and goals against, Corsi has developed a valuable system for teams to use in evaluating their offensive, defensive and goaltending quality.

(Kevin Hoffman-USA TODAY Sports)
Corsi worked extensively with Ryan Miller in Buffalo. (Kevin Hoffman-USA TODAY Sports)

Corsi’s talents in the field of statistical analysis should prove useful as the Blues attempt to get a firmer feel for whether Brian Elliott can be a true number one goalie, perhaps starting as many as 60 percent of games and facing far more shots as a result. Additionally, although promising prospective 1B Jake Allen has put up solid numbers at the minor league level, Corsi’s numbers should aid management in evaluating his progression at the NHL level. This is where Corsi separates himself from other goalie coaches that focus primarily on technique and motivational aspects. If Elliott or Allen feel they had a good or poor outing, Corsi’s system can shed more objective light on the issue.

Corsi’s evaluations keep goalies honest with themselves

The system is not a hand-holding exercise for goalies despite his own professional experience, however. For example, Corsi’s system doesn’t credit a keeper for making a save he “should have made,” such as a shot from the blue line. However, a breakaway or two-on-one that misses the net is considered a valid scoring chance and credited in evaluation metrics as an “unofficial save” — or a scoring opportunity the goalie squelched by eliminating open net with solid positional play. It also allows coaches to better evaluate the number, interval and effectiveness of scoring chances where the goaltender is expected to react. These determinations can help identify better defensive structures while limiting scoring opportunities from high-percentage locations In so doing,  this helps coaches and management figure out where defensive and goaltending weaknesses dovetail. For a franchise like the Blues that is yet again charting a new goaltending path and that had a strong defensive core exposed in the playoffs by speedy Blackhawks forechecking, these metrics should prove very useful.

Kevin Shattenkirk
Corsi evaluations aid in strategic matchups. (Rick Osentoski-USA TODAY Sports)

Team and player evaluations are routinely made using Corsi’s system

The system works by not only evaluating those shots that were stopped and those that went in, but whether the goalie is playing the game correctly. The system spreads to all players, with credit given to each player on the ice if a shot attempt is made and taking away a Corsi point for each one against. Skaters are also evaluated on the relative effect each has while on the ice, whether or not a goal is scored. This can help a team like the Blues, where coaching is often accused of excessive line juggling and the intangible effectiveness of certain players. Applied in depth, Corsi’s system should allow those combinations to be assembled more effectively, and at better times. By evaluating time of possession, offensive quality and whether the team is offering up golden scoring chances allows a franchise to make better personnel decisions on and off the ice. As the franchise enters yet another season of player evaluation and introspection, Jim Corsi will prove valuable in determining who stays, goes and plays together.