Introduction to CSSI

The Common Sense Scoring Index was an idea originally created by The Production Line’s Chris Hollis (of MotownWings at the time). The concept was simple: create a scoring system which would not ignore context in the statistics and would therefore create a much better system for tracking a player’s real contributions to his team.

In the summer of 2010, I got permission to resurrect the Common Sense Scoring Index for use during the 2010-11 NHL season. I made some material changes to the way things were worded and scored, but the concept remains the same: watch the game, record what happens, and create a scoring system which accurately tells us which players deserved the most punishment or credit for the way the games turned out.

The CSSI is scored for skaters using two tracking methods: Points Adjustments are used to accurately credit players for goals and assists scored.Furthermore, points are broken down into extended categories for tracking purposes. A player can be credited for doing more than one thing to aid in the creation of a goal. What’s more, assist credit and goal credit can be halved or eliminated altogether for a player, depending on the context. The Points Adjustments categories are as follows:

Screener’s Assist Given to a player whose body position prevented a goaltender from seeing a puck to make a save.
Third Assist Given to a player judged to be the third person in a play worth of earning an assist for a goal.
Fourth Assist Given to a player judged to be either fourth or fifth in a play worth of earning an assist.
Self-Assist Awarded to a player judged to have made an assist-worthy play on a goal he scored himself.
Non-Touch Assist These are given to a player who, by positioning, prevented a player from the other team from being able to make a play to prevent a goal being scored.
Bonus Assist Awarded to a player on a play which has been judged that, by its virtue, is special enough to warrant giving the same player more than one assist on the same goal.
Assist Lost Designed to keep track of times when an official assist has been taken from a player due to context.
Goal Credit Designed to track goals awarded or lost due to the context of a scoring play.

For an example of a complex scoring opportunity, let’s take the following hypothetical play:

As the other team skates out of their own zone with the puck, their defenseman throws a cross-ice pass to a streaking forward. While the pass is on its way, Brad Stuart steps up in the neutral zone, causing the forward to come up short on the pass instead of taking a big hit. Niklas Kronwall steps over to pick up the loose puck and fires it back up ice to Pavel Datsyuk. He and Zetterberg run a fancy give-and-go play at the opponent’s blue line to gain entry to the zone. While Datsyuk is forced wide, Tomas Holmstrom steps in front of the goalie to create a screen. Datsyuk skates behind the net and bounces the puck off the back of the goal to avoid an overzealous defenseman before finding Zetterberg in the slot for a one-timer past a screened goalie. Official scoring on this play would be Henrik Zetterberg from Pavel Datsyuk and Niklas Kronwall. The adjusted scoring play would add a third assist to Brad Stuart for separating the other team from the puck in a way that leads to a goal. It would also create a self-assist for Zetterberg for helping bring the play into the zone. Datsyuk’s fancy stickwork passing to himself off the back of the net would be good for a bonus half-assist. Finally, Holmstrom would be given a screener’s assist for preventing the goaltender from seeing the shot.

Along with Points Adjustments, Plus/Minus Adjustments are used to track a player’s contribution to the game in ways that are not contingent solely upon points being scored. Plus/Minus Adjustments come from a variety of ways and can help or hurt a player’s rating without being contingent solely upon whether the team was lucky or unlucky enough to have a goal be the end result of the play. The Plus/Minus Adjustments 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 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 his team.
Overall Plus Given to a player whose overall play during the game was ascertained to have positively impacted puck possession for his team in a way that he was not properly credited for in the official stats.
Overall Minus Given to a player whose overall play during the game was ascertained to have negatively impacted puck possession for his team in a way that he was not properly credited for in the official stats.
Penalty Plus Given to a player who worked to force the opposition to take a penalty.
Penalty Minus Given to a player who either committed a bad penalty of his own or made a mistake which forced his teammate to take a bad penalty.
Shift Change Plus Created to allow for correction of official plus/minus stats to either give or take away credit on a play when a goal is scored during or after a line change in which a more deserving player was not on the ice during the scoring play.
Shift Change Minus Created to allow for correction of official plus/minus stats to either give or take away credit on a play when a goal is scored during or after a line change in which a more deserving player was not on the ice during the scoring play.
Power Play Plus Lost Designed as a minus category to clear undeserved plus ratings from players who were on the ice when a goal was scored between the time a power play ended and the penalized player was able to get back in the play.
Penalty Kill Minus Cleared Designed as a plus category to clear undeserved minus ratings from players who were on the ice when a goal was scored between the time a power play ended and the penalized player was able to get back in the play.
Goal Against Minus Cleared Given to a player who was deemed to have been in position and not-at-fault for a goal scored. These are also given to players on the ice for a bad goal against. A player may have minuses added on for specific faults, but he will have his official minus cleared to track goaltender fault.
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.

To borrow from the example above, let’s say that after making the step-up in the neutral zone to create the turnover which led to the goal, Brad Stuart stepped off the ice in favor of Jakub Kindl. Kindl does nothing in the time between when he steps on the ice and when Detroit scores to make himself a part of the play. In this situation, Brad Stuart would be given back the official plus while Kindl’s is taken away. Aside from that, his excellent defensive work to create a goal would lead to a bonus Goal-Scored Plus rating.

For goaltenders, there are three statistical categories which are tracked by CSSI. They are:

Bad Goal Given each time a goalie allows the puck in the net on a shot or play that he is deemed to have been expected to make the stop.
Goal Forgiven Credited to a goalie who was judged to have done everything right to prevent a goal, but saw one getting by him through bad luck or bad play by his defense. An example would be for one of his own players deflecting a puck past a goalie.
Head-to-Head Plus/Minus A rating of -1, 0, or +1 given to a goalie as a measure of how well he played in comparison to the opposing goaltender.
Overall Game Rating A rating on a scale of -3 to +3 (0 being average) given to a goaltender for his performance during a game. Ratings on the severe end of the scale should be used very judiciously.

Bad Goals are something of a hybrid stat (and, like all the other stats, can be halved). They are meant both to track for a goalie the number of goals he gave up that he should have been expected to have stopped, but it also lets us cleanly track player pluses and minuses. When a bad goal goes by, the official minus for each of the players will be lowered by the amount the goal was considered bad (a half-bad goal would clear half a minus for each player on the ice).

The Head-to-Head plus minus is meant solely to track if there is a means of considering a goalie “clutch” or not. This is a purely experimental category, as we are looking to gather data on the conceptual phenomenon of a goalie who may not have very good traditional numbers but can be expected to “get the job done” in comparison to his competition on a regular basis.

The Overall Game Rating will measure a goalie against standard expectations as judged by the CSSI scorer. Since there is no agreeable threshold for how many shots allowed and what kind of quality shots will equate to any certain level of expectations, the CSSI scorer (with the help of commenters) will make a judgment based on how well a goalie played and whether he was a positive, negative, or neutral factor in the outcome of the game.

With the help of commenters throughout the season, this system creates a very balanced view of the contributions members of a team put in to help assure that team’s success.