INTRODUCTION
League average: .918 EV SV%, .866 PK SV%, .912 PP SV%
SV% By Line
1 – 0.911
2 – 0.917
3 – 0.921
4 – 0.923
To properly analyze a goalie you have to use stats that isolate them from the defence in front of them as much as possible. The best way to do this is to use “above expected” stats which compare what goals a goalie did allow to what a goalie would be expected to allow based on the quality and quantity of the shots he faced.
GOALIE STATS
Goals Saved Above Expectation (GSAx) is the best metric we currently have because it accounts for shot location and various shot other aspects (whether it was a rebound, whether it came on the rush) that impact shot quality.
including (venue-adjusted) shot location parameters (which GSAx does) makes it a better metric than normal raw save percentage, a stat that we’ve used for decades to evaluate goalies. But it could certainly be improved, too.
GOALS SAVED ABOVE AVERAGE (GSAA)
This is a cumulative stat that represents the number of goals allowed by a goaltender compared to the number of goals that would have been allowed by a league average goalie.
GOALS SAVED ABOVE AVERAGE PER-30 (GSAA/30)
This is a rate version of GSAA, and tells us how many goals saved above average a goalie has per every 30 shots he has faced.
The primary difference between GSAA/30 and GSAA/60 in terms of application is that GSAA/30 helps equalize goalies who face varying workloads. Despite not accounting for workload, GSAA/60 is still useful, as goalies that can handle an increased workload at a consistently high level, such as Henrik Lundqvist, are extremely valuable.
GOALS SAVED ABOVE AVERAGE PER-60 (GSAA/60)
The primary difference between GSAA/30 and GSAA/60 in terms of application is that GSAA/30 helps equalize goalies who face varying workloads.
Despite not accounting for workload, GSAA/60 is still valuable, as goalies that can handle an useful workload at a consistently high level, such as Henrik Lundqvist, are extremely valuable
SABERMETRICS AND GOALIES
(July 2007)
Goalies are harder to evaluate statistically then position players (at least offensive ones).
The problem of goalie sabermetrics comes down to the poor choices of the standard goalie statistics that are kept.
One common statistic is goalie wins. Goalies do not win games. Teams win games.
A goalie on a weaker (non-playoff) team who may be good (such as Olaf Kolzig or Christobal Huet or Cam Ward) will not be a league leader in wins because his team doesn’t win very often
Another common goalie stat (arguably the most popular) is goals against average. The number of goals a goalie allows per 60 minutes of play may partially evaluate the goalie, but it also shows how good the defence is in front of a goalie. If a goalie faces lots of shots or high quality shots it is far harder to have a low GAA then if he doesn’t. This statistic is also highly dependant upon the team in front of the goalie.
Shutouts are another common goalie stat. They record how many complete games a goalie played without allowing a goal. They say nothing about his result in the non-shutout games. Highly team dependant since it is far easier to record a shutout when your team plays good defence in front of you.
The most meaningful, but still imperfect, statistic is saves percentage. It records the percentage of shots a goalie faces are saved. It is easier to have a good saves percentage if you face low quality shots instead of high quality ones, but at least the quantity of shots is normalized for.
MEASURING GOALTENDER TALENT (2 ARTICLES)
Goalies are individuals, and as a result, we should expect there to be some level of talent disparity. If someone suggests that all goalies are the same, they are wrong. If someone suggests that we can’t determine through statistics which are the more talented goalie, they are wrong.
STATS INTRO
Quality Starts is the best measurement in how often a goaltender actually keeps the team in a winnable situation.
Most goalies are equally consistent, just some are better on average than others.
The best goaltenders will then be the ones that help the most, and thus have the best save percentage.
GREEN SHOTS & RED GOALS
(Dec 2014)
76 percent of goals in the NHL this season have been scored off Green Shots, including 30 percent on plays that involved either a pass or possession moving across the Royal Road.
Boyle has calculated the expected save percentage on a clean shot to be .949, but it’s .651 on shots immediately following a pass.
So what statistics can we use to assess every goalie
Quality starts
This statistic was developed by Robert Vollman, author of the Hockey Abstract series of books devoted to statistical analysis in hockey. He defined a quality start (QS) as a game when the goalie stops more than the median save percentage for the League (currently .917) or gives up less than three goals while stopping .885 or more of shots faced.
Goals Saved Above Average
Another relatively new comparative goaltending statistic available at hockey-reference.com, Goals Saved Above Average (GSAA) is essentially a plus-minus for goalies compared to the NHL average. In other words, how many goals has a goaltender saved compared to an average goalie facing the same workload. Or, in the case of a negative number, how many more goals has he surrendered. Though GSAA includes penalty-killing, tends to favor higher workloads, and might be better expressed as a per-game average, it’s interesting to see where some of the top goaltenders rank.
Adjusted Save Percentage
The above-mentioned statistics treat all shots equally, and any goaltender at any level can tell you that’s not the case. At war-on-ice.com they have introduced Adjusted Save Percentage (ASV%), which weights a goalie’s save percentage based on the distance of the shot faced. Simply put, the closer the shot, the more likely it is to go in. By factoring distance into each shot, the ASV% provides an additional layer of context about the quality of shots faced by each goaltender. If a goalie’s ASV% is lower than their standard save percentage, it should indicate the mainstream number is slightly inflated because he faces easier shots. Conversely, a higher ASV% indicates he is facing tougher shots, at least based on distance.
IT'S TIME TO SCRAP GAA
(Mar 2015)
Goals against average is altered by a variety of factors, and it cannot realistically tell us anything about an individual goaltender. It is simply a team stat. Nothing more, nothing less.
Goals Against Average Does Not Reflect Performance.
As far as goaltender evaluating is concerned, goals against average is basically a crummier, low-brow version of save percentage.
The factors omitted by goals against average contain the information that we should be judging goaltenders with, instead of glorifying the end result
(May 3, 2016)
Comments