January 16, 2015 Leave a comment
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.
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:
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.