Scoring Chances

There are many ways to measure performance in a game – eye test, scoresheet, standard metrics, advanced metrics, etc.

To me, the best indicator of overall performance is Scoring Chances. We define a scoring chance as any shot on net from within the “scoring area” (inside the dots and below the tops of the circles).Statistically speaking, NHL goalies have a .855 save percentage inside the scoring area, and a .958 save percentage outside of it (reference: http://www.hockeybuzz.com/blog/Ryan-Wilson/Home-Plate-Save-Percentage/177/62065). Any shot from within the “scoring area” has a much greater chance of beating the goaltender.

Scoring Area

Why do I consider this the best indicator of performance? Critical moments. Scoring chances are the critical moments in any game that dictate the outcome. There are thousands of innocuous plays in every hockey game, but only about 20-40 that qualify as a scoring chance. How you perform in these instances says a lot about how you played the game.

How do we measure scoring chances? After every game, I go through and watch every shot for and against. The shots that are released from within the scoring area are recorded as scoring chances. I then record responsibility for each chance – for and against. This is the subjective part of scoring chances, sometimes it is hard to say who is more responsible for a certain play. We assign primary and secondary responsibility for every play – the difference between primary and secondary is sometimes marginal, but there are almost always at least two players who could have changed the outcome of the play. I don’t look at primary vs secondary very often, mostly overall scoring chance +/- (your involvement in chances for minus your involvement in chances against).

We also measure a stat called absolute scoring chances. Absolute scoring chances measures the number of chances for and against while you were on the ice, regardless of involvement in the play. This indicates if a player, line, d pair is more of a positive or negative influence on the game overall. I also feel this is a good indicator of matchups – if you were playing against an opponents top line and were even or better in absolute scoring chances, that is a good game.

Here is a look at our stat sheet from after a typical game:

Untitled

Total +/- indicates a player’s involvement (primary or secondary) in scoring chances. Absolute +/- is their on ice presence for any even strength scoring chance. In this game, two players had poor performances (-4 and -5 total) while a few (the +2s total and +3 and +4 absolute) had good performances.

While there is always a big picture evaluation, scoring chances gives you a snapshot of who was involved and who influenced the game in a positive or a negative manner. Teaching through scoring chances gives you an opportunity to improve your performance in the critical moments that define a hockey game.

Scoring (Chances)

The game of hockey is a fast paced flow sport that demands many different actions and reactions for each player. These events can be seen and understood in many different ways and how success or failure is measured can, at times, be subjective. One of the more cut and dry areas of hockey analytics and statistics is scoring chances. Every team that plays at a high level looks at the impact of scoring chances on a game. It is safe to assume that most teams always attempt to out-chance the opponent.

What is a scoring chance? There is no universal definition, but it is a stat that is universally tracked. At UMass, we define a scoring chance as a shot from Grade-A (the area in between the faceoff dots, from the top of the circles down to the goal line) that hits the net. While this eliminates shots that hit the post and pucks that roll untouched through the crease (among others), it is the most objective way to look at scoring chances. We also look at scoring opportunities which include plays that would have been a chance if the puck was on net.

Why are scoring chances important? In hockey, the object is to score more goals than the opponent. While there are always outliers, it is safe to say that teams score more goals from the scoring area pictured than from the perimeter of the ice sheet. As a coach, I want to know how many scoring chances my team generated and how many we surrendered. I also want to know what our shooting percentage is on scoring chances and what our goalies’ save percentage is on scoring chances against. These are numbers that I can use to quantify our performance in the most important area of the ice, both offensively and defensively.

Scoring chances and scoring chance involvement can be tracked on an individual level as well. While this begins to enter the more subjective range, it is a way to see how a player is getting involved both offensively and defensively. Defensemen will often be skewed towards the negative, while Forwards will skew towards the positive, as this is the nature of their position. For this reason, individual chance performance should be measured against a few different numbers, including team averages, linemate averages, and averages per shift (40 seconds). This allows players to be fairly evaluated against the overall performance of their teammates and more specifically to the players they play with on a frequent basis.

I certainly understand and appreciate that there is much more to hockey than scoring chances, however I feel that looking at and tracking scoring chances is the most effective way to get an overall view of a team’s performance. It measures the ability of the player and the team to perform when it matters most.

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