NHL Goalie Shot Analysis

In today’s NHL, having an elite goalie is necessary to make a playoff push, let alone ensure a playoff spot. However, when analyzing a goalie, basic hockey stats like shots and goals against average don’t tell the full story for a goalie. So for the past few months, I have been looking at previous NHL data from MoneyPuck¬†and trying to find a few trends and calculations that can shed new light on a goalies performance. From the data, I defined a few constants and made a definition of what a dangerous shot on a goalie is. First, the constants:

X Coordinate (adjusted) Y Coordinate (adjusted) Danger Level
Slot From 40 to 90 From -22 to 22 High
Left Circle From 32 to 82 From -43 to -7 Medium
Right Circle From 32 to 82 From 7 to 43 Medium
Point From 20 to 35 From -43 to 43 Low

Note: the numbers are relative to the MoneyPuck database. Additionally, I chose not to define what a netfront shot or a deflection is due to the fact that they usually originate from a rebound or a pre-existing shot, so the goalie is sometimes disadvantaged due to the nature of the shot.

Now, for the definition of what a dangerous shot is:

A dangerous shot on goal is a shot that on average, makes the goalie make a skilled save, rather than a positional or instinctive save. For example, a shot in front of the net allows the goalie to rely on his size and position instead of skill. However, a shot from 20 feet out in the slot forces the goalie to rely on skill.

From these definitions, I looked at the historically good goalies from the past 4 seasons, in my opinion. I looked at Ben Bishop, Sergei Bobrovsky, Marc-Andre Fleury, Braden Holtby, Martin Jones, Henrik Lundqvist, Matt Murray, Carey Price, Jonathan Quick, Tuukka Rask, Pekka Rinne, and Andrei Vasilevskiy.

From looking at their numbers, I saw a couple of interesting trends:

  • The change in dangerous shot percentage (dangerous shots saved per dangerous shots in total) shows the improvement in a certain area
  • Compared to the general save percentage, the dangerous shot percentages tend to show where a goalie succeeds and where a goalie is disadvantaged.

Let’s look at some examples. The data I looked at started in 2010 and ended in 2016. I calculated their cumulative save percentages, along with yearly percentages and playoff percentages. Let’s take a look at Ben Bishop’s percentages versus and successor, Andrei Vasilevskiy.

Goalie Data Total Save Percentage Data Total Point Shot Save Percentage Data Total Slot Save Percentage Data Total Left Circle Save Percentage Data Total Right Circle Save Percentage
Ben Bishop 94.302% 98.013% 91.741% 96.102% 96.869%
Andrei Vasilevskiy 93.813% 97.832% 91.852% 94.595% 95.863%

From this data, we can see that Bishop better percentage wise. However, Bishop has faced more shots in the time frame and is a more seasoned goalie. The data for Vasilevskiy shows that he has room to grow even though he is arguably an elite goaltender. Once the data from the 2017-18 season is released, these numbers will show if Vasilevskiy has outperformed Bishop after Vasilevskiy has become the starter for the Lightning and Bishop was traded away to the Kings and then the Stars.

Another big finding I had actually turned out to be its own statistic: shots per goal. Similar to goals against average, shots per goal allows coaches and general managers to know how often a goalie will let up a goal. Furthermore, it allows for a comparison between regular season hockey and much more intense playoff hockey. A great comparison is the former tandem of Marc-Andre Fleury and his successor Matt Murray.

Let me give a bit of background on this comparison: Marc-Andre Fleury has been the Penguins’ starting goalie since the 2006 season. When he got hurt near the end of the season in 2015, Matt Murray stole the starting spot and carried the Penguins to a Stanley Cup championship. The next season, Murray and Fleury were one of the best goalie pairs in the NHL, which allowed the Penguins to gear up for a repeat. When Murray got hurt during warmups in Game 1 of the playoffs, Fleury helped the Penguins get into the conference finals. Murray came back from injury and led the Penguins through the conference finals versus the Senators and helped the Penguins win their second back-to-back Stanley Cup. That offseason, Fleury was drafted by the Las Vegas Golden Knights in the expansion draft and is having a career year with his new team. Currently, Murray is on the comeback trail after taking a personal leave due to the passing of his father.

With the background, Murray and Fleury were compared a lot during the 2016-17 season. So, here is how their shots per goal line up in the regular season and playoffs.

Goalie Regular Season Shots Per Goal Playoffs Shots Per Goal
Marc-Andre Fleury 14.594 17.838
Matt Murray 17.532 21.579

As the data shows, Murray was, on average, better than Fleury last season. However, we can see that both players improved their game by at least 3 shots during the playoffs. This increase can help explain the Penguins’ excellent performance in the playoffs.

Some take aways from the shots per goal statistic:

  1. I think it is a better way to determine the “luckiness” of a goalie over a short span of games. If the goalie has an extremely high shots per goal over 5 games and they’ve won 4 or 5, the goalie has been playing extremely well. If the goalie has a low shots per goal over the 5 games, with winning 4 or 5, then the goalie has either been lucky or has a good shot-blocking defense in front of him.
  2. Shots per goal allows for a more game to game discussion while goals against average seems to shed light on season to season performance.

From all this data, I have learned a lot about goalies and their strengths and weaknesses. Stay tuned for some more goalie analysis, including a goalie effectiveness statistic.

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