As the “Summer of Analytics” wraps up and various NHL camps get underway, there is a palpable urgency apparent from some NHL front offices to find the key to success by expanding their analytics departments. The task teams are currently undertaking is to identify their strengths and weaknesses by conventional and progressive means. Once they do this, they can then come up with a plan to exploit their strengths and improve the areas of weakness.
While there is no secret weapon or magic trick that will suddenly make a good team from a bad team, there are some team strengths that are more important to success than others. In looking at successful teams over the past several seasons, one such strength stands out from the rest: Shot suppression.
Shot suppression is a fairly basic concept, but because it is not as exciting as a high powered offense or as easy to identify as say an excellent penalty kill, it is not often discussed during broadcasts or major media analysis shows. Shot suppression is one of the true measures of the quality of a team’s defensive structure and systems. Even in analytics, this component of team play can be overlooked when we use percentages such as CF% (Corsi For) or FF% (Fenwick For). Percentages are terrific and useful for many things, but one of their shortcomings is that they mask Event Rates.
Event Rates are often expressed as whatever metric is being used “Per 20” or “Per 60”. To understand how aggressive an offense is, CF or FF rates are very useful. For example, the San Jose Sharks had the highest CF60 in the league at Score Close last season with mark of 63.6 and were third in the league in FF% (most popular team possession measurement tool) at 54.9%. The Ottawa Senators were second in the league in CF60 with a rate of 63.2, but were twelfth in the league in FF% at 50.8%.
When the CA and FA rates are added into the mix, we can see which teams allow more shots than others. When used in combination with the team’s CF and FF marks we get a picture of a team’s event rates.
You will note that the best or most successful teams in the league are not at either extreme in terms of event rates. They are not super low event like the New Jersey Devils nor are they super high event like the Ottawa Senators. Teams with very low event rates both in terms of shots for and shots against often struggle to produce enough offense to consistently win games. This was obvious last season, when Devil’s goalie Cory Schneider played very well but was consistently losing games because of a lack of offensive support. Likewise, teams with very high event rates in shots for and against tend to score quite a bit, but they also tend to give up a lot of goals.
The real question is: what is most important? Shot suppression or a prolific offense? Looking back over the past several seasons at teams that were successful both during the regular season and the playoffs may lead us to an answer.