Season CSSI Wrap-Up: Plus/Minus Adjustments

When we last left you on on the subject, we took a look back at the season-long CSSI numbers for points adjustments. Those numbers gave us a very good indication of how each of the Red Wings' players did in driving Detroit's offense this season. I intended the points adjustments to help us factor in the things that players do to help the team score goals that they don't necessarily get credit for on the official scoresheet. Today, we'll look at the other side of the coin in the CSSI adjustments, the plus/minus adjustments.

For context, nobody can quite agree upon what exactly a person's official plus/minus tells you. As a statistic, it is only meaningful to give an indication of what happened at even-strength, but does a horrible job of telling us why. There are so many factors that a player cannot control which impact his official plus/minus score that the statistic as-is does nothing more for us than fit neatly together with other (and sometimes contrary) statistics to tell us what we want to hear. A puzzle piece which fits together with dozens of other pieces tells us nothing about the overall picture.

What I tried to accomplish with plus/minus adjustments was a ratings system that made sense, one that people can look at and from which they can discern a meaningful comparison without myriad arguments about how situational ice time, relative goalie strength, and overall ability of linemates and competitors would skew the numbers. I wanted to try to get as close as possible to achieving the goal of creating a statistic that could best be used as a measure of a player's defensive ability. I think that with the help of the readers this season, we accomplished this feat.  Join us below the jump for a look at the numbers.

Where there were only eight categories to fit the offensive contributions, there are thirteen plus/minus adjustments to tell the story. These categories are as follows:

Goal-Scored Plus: These are plus ratings awarded to a player when it was deemed that a defensive contribution he made on the ice (whether by starting or preventing transition) helped lead directly to a Red Wings goal.
Coverage Minus: Given to a player who made a mistake in defensive coverage that was determined to have led directly to an opponent scoring. 
Turnover Minus: Given to a player who was judged to be directly or indirectly at fault for a turnover that the opposition used to score a goal against Detroit.
Overall Plus/Minus: Given to a player whose overall play during the game was ascertained to either have positively or negatively impacted puck possession for the Red Wings in a way that he was not properly credited for in the official stats.
Penalty Plus: Awarded whenever a player was deemed to have made a play to sufficiently force an opposing player to take a penalty to prevent a goal or a high-percentage scoring chance. As a note, there was a rather strict application of this rule. Pluses were not given out to players who were simply determined to be the victim of an opponent being stupid.
Penalty Minus: Given whenever a Red Wings player took a penalty that was not considered a "good" penalty to take or when a player made a grievous mistake that forced one of his teammates to take a penalty. 
Shift Change Plus/Shift Change Minus: This category was created to award and take away pluses when a player who did more to help create a Detroit goal came off the ice for a line change before the goal was scored.
Power Play Plus Lost: This is a minus category created to take away official pluses given to players who were on the ice for a goal that was scored for Detroit in the short time between the end of a Detroit power play and when the penalized player was able to get back into the play.
Power Play Minus Cleared: Again, the opposite of the category above, this category is to to clear a minus for a Detroit player who was on the ice for a goal against in the intervening time between the end of a successful Red Wings penalty kill and the player being considered "back in the play."
Goal Against Minus Cleared: This category is for players who were on the ice for a goal against, but were not judged to have been at fault for the goal being scored. This is to prevent a player who is playing his position as expected from getting a minus when other people on the ice make mistakes.
Goal Saved Plus: Given to a player who does anything that prevents what should be considered a surefire goal. Lifting the stick of a player preparing to receive a pass on a wide-open backdoor and outright making a save on a shot are both examples of this.

(Games Played column added for comparison's sake)

If anybody wants to know why Datsyuk is a strong Selke candidate in a year where he only played 56 games, then the first column should be a good hint. His +15 on goals scored means that he was better than everybody else on the team at turning defense into offense. The fact that an 82-game pace would have made him a +22 in that regard says wonders. I was also interested to see how high Bertuzzi's number in that regard is. The going consensus around Red Wings nation was that Bertuzzi played very well defensively and I think this number helps to put a number to that. Of course, that category isn't purely defensive, as the number is dependent upon the Wings scoring a goal, but it does help us explain pretty well which Wings were driving the transition game that has been so crucial to Detroit's past success.

The coverage minus column is very interesting, as nobody found himself failing to cover his man or zone in the defensive end more than Darren Helm. Part of this can be attributed to the CSSI's habit of occaisionally giving minuses to penalty killers and part of it can be explained by the system's inherent bias against centers (more defensive responsibility equals more opportunity to mess up). This, by no stretch means that Helm played badly defensively though, his team-leading overall plus/minus rating shows that. It's just that a defensive center playing in defensive situations is going to get exposed occasionally. Also of interest is that the Wings' best defenseman earned the second-most coverage minuses. While it's not a stretch to imagine that Ericsson would find himself out of position about that often, I was a bit surprised to see Lidstrom punished so much, even when taking his quality of competition scores into it.

For turnovers, nobody knew how to create an odd-man rush against Detroit quite like Nik Kronwall. This is the risk you take with an offensive-minded D-man. The good news is that the rewards he brought more than outweighed that, as Kronwall was among the three out of Detroit's seven defensemen who's adjusted plus/minus was higher than his official one.

The difference in overall pluses and minuses does a good job of showing which guys were more consistent and which were more streaky. Lidstrom is the model of consistency here with +31 overall to only 1.5 minuses. You can see that Hudler actually earned more overall pluses than Bertuzzi, but he pissed most of those away in also earning seven minuses to Bert's 1. Ericssons pluses and minuses were very neatly broken into streaks, as he earned seven overall pluses or half-pluses in a stretch between November 5th through December 10th before falling into a streak of seven overall minus ratings from the beginning of January up to February 7th.

Penalty differential showed very clearly the strict differentiation between earning a penalty plus and deserving a penalty minus. Only four players were an overall plus in that regard (Datsyuk, Filppula, Helm, and Miller), while only the most offensive of defensemen in Kronwall was able to pull more than 2 earned calls in Detroit's favor. I'm happy with the way that turned out though. Nobody expects defensemen to draw penalties. Holmstrom's gamble is a fun case to look at because would he draw so many penalties if he weren't doing the things that caused him to also take as many? All I know is that watching him end Red WIngs power plays got very frustrating at times. Franzen being such a big body is perhaps not going to draw as many calls as a smaller person, but two is unacceptably low. Speaking of unacceptable, Ericsson led the team in minor penalties taken (30) and got credit for 21 of them being bad. That is a huge number.

The GA+ category above, for minuses cleared when a player wasn't at fault for a goal against is the ultimate reason why position should be taken in consideration when looking at the numbers. Pretty well across the board, wingers got a lot more breaks than anybody while centers got a few more breaks than defenseman. As noted elsewhere, the more defensive responsibility a player has, the more chances he has to make a mistake. Todd Bertuzzi ended up tied for the lowest official plus/minus rating of anybody on the team, but was the 7th-best among Red Wings players in adjusted plus/minus. Can anybody who watched this season honestly tell me that Bertuzzi was as bad defensively as Jiri Hudler?

There is plenty more to be gleaned from these numbers and, next season, I will be tracking these game-by-game, so we can recognize trends better as they happen. Thanks again to everybody who helped develop this system as the season went. I am extremely satisfied with how rewarding this season-long project turned out.