Context is something that all sports statisticians look to achieve but have yet to find a perfect method for doing so. Hockey stats in particular are tough to judge based on raw data alone. There are so many players who are used in different situations and every stat must be taken with a grain of salt. This is especially true for shot-based metrics like Corsi (even strength shots attempted) and scoring chances. A player who starts a majority of his shifts in the defensive zone is going to be on ice for more shots and scoring chances against no matter what because he starts so many shifts in his own end. The same can be said for a player who is regularly matched up against tougher competition, only to a lesser extent if they are given a territorial advantage.
Take a player like Brandon Sutter for instance. He plays tougher minutes than most players in the league and has a raw scoring chance percentage of 44.5%. That looks very bad at first glance, but what would his numbers look like if he started more than 34.8% of his shifts in the defensive zone? Thanks to the outstanding work of George Ays from Blueshirt Banter, we can adjust player's scoring chance ratings to see what they would look like on a level playing field.
Using scoring chance data from teams who are currently being tracked, Ays figured out that every extra start in the offensive zone a player has is worth 0.425 in scoring chances. Using this model, we can figure out what the Hurricanes players' scoring chance numbers look like adjusted for zone starts. What we are going to do is look at each player's zone start data from Behind The Net to see how many extra shifts he begins in the offensive zone. Using that, we get an adjustment number and apply it to the player's even strength scoring chance differential. A breakdown of this data is coming after the jump.
Carolina Hurricanes Scoring Chances Adjusted for Zone Starts
|Player||EV TOI||Diff||SC%||OZ%||Adj. Chance Diff||Adj. Chance Diff/60|
EV TOI = Even strength time on ice, Diff = even strength scoring chance differential, SC% = scoring chance percentage, OZ% = offensive zone start percentage, Adj. Chance Diff = Scoring chance differential adjusted for zone starts, Adj. Chance Diff/60 = Adjusted scoring chance differential per 60 minutes.
As you would expect, the forwards who are starting more in the defensive zone come out looking a lot more favorable after adjusting their raw scoring chance numbers. Chad LaRose, in particular, looks excellent. Even strength scoring chances were already going in the Hurricanes' favor when he was on the ice and he's been doing it while starting more of his shifts in the defensive zone. I always felt that he was really underrated but I do not remember him ever performing this well territorially. It's a shame that he just missed the 20-goal plateau because this very well could have been his best season in the NHL and that would have been a nice milestone for him to achieve. Still, it's hard to complain with his performance this year because he did a lot of good things even when he wasn't scoring.
Brandon Sutter is apparently performing better than other players who are used in similar situations as him. It does make sense because he manages to be a pretty efficient offensive player for a third-liner and that's tough to do when you start in the defensive zone as often as he did this year. Sutter was on-ice for the 6th most scoring chances among forwards and his shot rate actually improved from 1.76 to 2.08 shots per game this season. He does a much better job at driving the play forward than the raw numbers give him credit for. The other heavy-lifter, Patrick Dwyer, doesn't look as good through adjusted chances but he still comes out as a positively rated player.
The one bias against this kind of model is that it unfairly punishes players who are used in easier situations but that isn't true when you look at the table above. Jeff Skinner, Jussi Jokinen and Drayson Bowman all played softer minutes and they are positively rated through this model. Skinner is actually very highly rated if you go by his raw differential because he was blowing away his competition and doing his job of keeping the puck in the offensive zone more times than not. The idea here is that it punishes players with easier minutes who fail at driving the play at an effective rate. That was the case for Tuomo Ruutu and just about every fourth liner on the team.
Eric Staal is another player who managed to outchance his competition at an effective rate and he did it while playing pretty tough minutes. His role wasn't as difficult as Sutter's, but he didn't get as many offensive zone starts as some other top-sixers and he was one of the team's better players at controlling scoring chances and one of the best at creating them. Staal was also one of the team's tough minute players in terms of quality of competition, so it is a good sign that he's staying well above the 50% mark here. He isn't the best defensively and he isn't the offensive powerhouse he used to be, but Staal is still a terrific first line center.
|Player||EV TOI||Diff||SC%||OZ%||Adj. Chance Diff||Adj. Chance Diff/60|
Unsurprisingly, Tim Gleason and Bryan Allen are the highest rated defensemen here with Allen seemingly performing much better than Gleason in a similar role. Allen's play dropped off a lot in March but he is going to leave a huge hole to fill if he does leave for free agency. I am a little suspicious about how his knee will hold up throughout the course of another year, but he was great in a shutdown role this season and I think it would be a bad idea for the Canes to let him walk away for nothing. Keeping that in mind, look at how extreme Gleason & Allen's zone starts are compared to the rest of the defense corps. They had a tougher role than any other defenseman on the team by a wide margin and I think that will be a problem going into next season if Allen does indeed walk.
Seeing how the rest of the defense corps came out negatively rated in their respective roles, I have a hard time imagining any of them will quickly adjust to a shutdown role next season. I think part of the problem might be the coaching staff giving the bulk of defensive zone draws to just one defense pairing instead of spreading things around, but it's hard to blame them for doing that because of how effective Gleason & Allen were as shutdown defensemen. Still, finding another shutdown defenseman might be something for Jim Rutherford to look for this off-season because I am not sure if McBain, Harrison, Faulk or Pitkanen can handle that role. That being said, Faulk and Harrison played against tough competition this season and could possibly do it next year even if their numbers adjusted for zone starts look pretty brutal.
This method isn't perfect, but it does help us add context to some of the raw numbers to see who is more effective in their roles. We can see that some of the Canes tough minute players like Sutter, Dwyer & Allen are doing their jobs effectively while others could be doing a lot better. This should also give us a better idea of what needs should be addressed this off-season but that's another post for another day.