For awhile now, a very controversial discussion has been circulating amongst the hockey analytics community regarding shot quality and how it can be effectively measured. As any hockey fan knows, there are low quality shots, high quality shots, and many different “categories” in between. However, it is hard to measure these over time and effectively measure which teams or players are getting the best shots or the highest amount of shots in “quality” areas.
Recently, war-on-ice.com has added scoring chances to their data on their site, and provided a fairly clear definition of how they classify a scoring chance, which can be seen here:
So for this post, I am looking at team play and which teams have been able to get quality shots so far in the 2014-2015 season. Using this definition (which has multiple dimensions and is very well explained), I can take data provided and compare teams to see if scoring chances contribute to team success.
The following plot shows team scoring chances for vs. team scoring chances against per 60 minutes of even strength 5v5 play. I have added labels for teams who are succeeding in the standings, and any of those that are significantly different from the majority of the group that is clustered in a fairly small range:
Teams like Tampa Bay, Chicago, and the New York Islanders are evidently benefiting from generating a high number of scoring chances for while limiting the number of scoring chances against them. This has led these teams to the top of their divisions and allowed them to excel. Something that I specifically like are the numbers generated by Nashville and Florida, who do not necessarily generate a large number of scoring chances per 60 minutes but have put together good defensive systems that keep oppositional chances to a minimum.
Putting these numbers into a greater context is important, which is why I have used war-on-ice.com to compare the teams of this year to teams of past years. I examined teams from the 2005-2006 season to the present season, looking to see how well teams like the Islanders and the Stars are doing.
Shown here are the top 15 teams since the 2005-2006 season in SCF60 at 5v5. Both the Islanders and Stars of this season are included in this group, and actually both rank in the top 11 of the list. This is impressive; basically, these teams are generating as many scoring chances as some of the most powerful offensive teams that have played the past few seasons. Washington ranks 1st and 2nd, which makes sense because Ovechkin tends to shoot from anywhere and gets to most shots in the league consistently. These two seasons would have been when he was really showing his offensive prowess. Included in this list are some pretty good teams of the past 10 years, and the Islanders and Stars should begin to get consideration for their dynamic offensive systems.
What I really want to look at now is how the bad teams are doing relative to past years; that is, the teams that struggle in the SCA60 category. Here is the top (or bottom) 15 teams in SCA60 since 2005-2006:
This table shows two things: the Toronto Maple Leafs are bad, and the Buffalo Sabres are worse. Currently, the 2014-2015 Maple Leafs are allowing the most scoring chances per 60 minutes of even strength play since the beginning of the analytics era. What is even more astounding is that the Leafs of last season are second in this category! The defensive system under Randy Carlyle is just atrocious and they struggle to limit quality scoring chances against. This statistic can be linked to poor play; last season, the Leafs fell apart and missed the playoffs, and now are currently on a quick decline out of the Eastern Conference playoff race.
While Toronto may allow a substantial amount of scoring chances against, the 2014-2015 Buffalo Sabres are allowing just 2.1 scoring chances per 60 minutes less than these Leafs while only generating 19.9 scoring chances for! This comes out to a SCF% of 37.7%; this means that the Sabres only get 37.7% of scoring chances during 5v5 play. This is horrible; teams need to be able to generate scoring chances in order to score (you can score on low quality, “non-scoring chance” shots, but it is highly unlikely and impossible on a consistent basis). I need not say more; the Sabres are bad and are doing all they can to construct a rebuild.
I want to examine one final thing: how are the good defensive teams doing compared to past years? Here is the visual for this one:
This list contains some of the best defensive teams of the past 10 years. Sorted by SCA60, these are the top 15 teams in limiting scoring chances against. Here you have the strong defensive New Jersey Devils (the “trap”), the always strong in the Detroit Red Wings (two-way players throughout the lineup), and two teams from 2014-2015: the Florida Panthers and the Nashville Predators.
So far this season, the Florida Panthers have been surprisingly strong. Although they have struggled to get wins, they have been fundamentally sound. This is evident by their SCA60 number; so far this season, their strong and sound defensive system has put them in 6th in the past 10 years. I like the makeup of this Panthers lineup, as they have combined a good group of young, talented players (Bjugstad, Ekblad, Huberdeau, Trocheck, Barkov) with the right veterans (Jokinen, Boyes, Bergenheim, Upshall, Campbell) to create a strong overall team that plays solid at both ends of the ice. I truly believe that the Panthers will make it into the playoffs this year, using a quality team system with everyone buying in as a group.
As I always mention, these numbers are simply one way to evaluate a team or a player, and many different statistics and viewpoints are needed to generate conclusions. For now, scoring chances are what we need to use to evaluate a team’s shot quality and how it is related to team success.
What I want to look at in the future is a weighted measure for scoring chances, that takes into account scoring chances for and against in all different situations (EV, PP, SH, etc.) and determines which teams are putting together a good overall system in terms of shot quality. Finding the right weights for PP, SH, and EV situations will lead to an accurate representation and will properly represent team shot quality for and against. This type of measure could explain a lot of different aspects of a team and could eventually lead to solving the shot quality issue (or at least I can hope it will).