FanPost

Visualizing Save Percentage Plus: Part Two 2012-13

Sarah Connors

Not all "average" even-strength goaltenders are equal.

In part one of this series I suggested a method for visualizing goaltender performance using Save Percentage Plus (SV%+), a statistic that normalizes save percentage against the league average. SV%+ above 100% indicates above average performance. I converted even-strength, short-handed, and all-situations save-percentages from the now defunct Extraskater into SV%+ data (esSV%+, shSV%+, allSV%+). The premise is that there are several ways to be a great goalie, that great performances can be heterogeneous, and to visualize this difference with data.

2012_13_zps8e33d47e_medium

Click to enlarge. esSV%+ (abcissa) plotted against shSV%+ (ordinate). Lines at 100% indicate league averages. Bubble size indicates allSV%+. The darker the bubble the higher the Fenwick Against (FA). Table and interactive chart data may also be viewed here . My selection criteria was 25 percent of total games played. For the 2012-13 season, this means that goalies who played 12 games or more were included.

2012-13 (12+GP) shSV%+ esSV%+ allFAcat allSV%+
Allen 101.00% 89.00% FA>250 94.00%
Anderson 178.00% 137.00% FA>750 151.00%
Bachman 94.00% 75.00% FA>250 77.00%
Backstrom 97.00% 92.00% FA>1250 98.00%
Bernier 101.00% 123.00% FA>250 114.00%
Bishop 103.00% 112.00% FA>750 111.00%
Bobrovsky 100.00% 135.00% FA>1250 131.00%
Brodeur 68.00% 102.00% FA>750 90.00%
Bryzgalov 99.00% 86.00% FA>1500 89.00%
Budaj 131.00% 94.00% FA>250 97.00%
Clemmensen 83.00% 65.00% FA>500 71.00%
Crawford 127.00% 123.00% FA>1000 120.00%
Dubnyk 155.00% 102.00% FA>1500 111.00%
Elliott 83.00% 101.00% FA>500 96.00%
Ellis 82.00% 101.00% FA>750 95.00%
Emery 142.00% 109.00% FA>500 114.00%
Enroth 110.00% 125.00% FA>250 110.00%
Fasth 132.00% 106.00% FA>750 113.00%
Fleury 91.00% 112.00% FA>1000 106.00%
Garon 69.00% 94.00% FA>500 86.00%
Giguere 111.00% 94.00% FA>500 97.00%
Halak 92.00% 89.00% FA>250 88.00%
Hedberg 68.00% 80.00% FA>750 76.00%
Hiller 78.00% 123.00% FA>1000 102.00%
Holtby 96.00% 117.00% FA>1250 111.00%
Howard 98.00% 131.00% FA>1500 116.00%
Khabibulin 85.00% 121.00% FA>500 116.00%
Khudobin 267.00% 98.00% FA>500 111.00%
Kiprusoff 76.00% 74.00% FA>750 75.00%
Labarbera 154.00% 108.00% FA>500 116.00%
Lehner 267.00% 121.00% FA>500 139.00%
Lehtonen 111.00% 108.00% FA>1250 106.00%
Lindback 142.00% 84.00% FA>750 91.00%
Lundqvist 96.00% 129.00% FA>1500 120.00%
Luongo 73.00% 102.00% FA>750 96.00%
MacDonald 116.00% 82.00% FA>750 91.00%
Markstrom 71.00% 92.00% FA>750 90.00%
Mason 203.00% 89.00% FA>750 106.00%
Miller 99.00% 109.00% FA>1500 105.00%
Nabokov 107.00% 94.00% FA>1500 99.00%
Neuvirth 109.00% 95.00% FA>500 99.00%
Niemi 112.00% 112.00% FA>1500 117.00%
Pavelec 86.00% 93.00% FA>1500 94.00%
Peters 116.00% 74.00% FA>500 82.00%
Price 70.00% 101.00% FA>1250 94.00%
Quick 96.00% 88.00% FA>1250 91.00%
Rask 103.00% 125.00% FA>1250 125.00%
Reimer 167.00% 108.00% FA>1250 117.00%
Rinne 78.00% 111.00% FA>1500 99.00%
Schneider 138.00% 114.00% FA>1000 122.00%
Scrivens 104.00% 102.00% FA>750 105.00%
Smith 79.00% 104.00% FA>1250 99.00%
Theodore 80.00% 85.00% FA>500 83.00%
Varlamov 101.00% 91.00% FA>1250 92.00%
Vokoun 75.00% 135.00% FA>500 110.00%
Ward 97.00% 96.00% FA>500 97.00%

The 2012-13 graph isn't very dark in comparison to the previous season as there were fewer fenwicks during the lock-out. There is less regression to the mean and the over-all performance is somewhat scattered.

League-wide save percentage averages are known to vary from season to season, just as the number of goals scored per game has historically varied. Because SV%+ expresses goalie performance against the mean it makes for fairer comparisons between seasons and between eras. In the above graph the physical position of the bubbles (xy coordinates) may be compared between visualizations. We can see, for example, that Kiprusoff was much worse in his final NHL season than he was the season before.

Goalies were generally less consistent in 2012-13 than the year previous. This is visible in the charts, but we can also express this league-wide consistency with numbers. Below is a chart expressing the variance of SV%+ for both seasons (numbers provided are standard deviations).

season shSV%+ esSV%+ allSV%+
2011-12 0.43 0.13 0.14
2012-13 0.42 0.17 0.16

Playing Short-handed is a Skill (?)

There is generally a larger amount of variance for short-handed performance. It's not uncommon for above-average goalies to perform well below-average when their team is down a man. Such performances are in the top-left quadrant of our vizaualizations. As pointed-out by aluchko in the comments from part one:

The correlation between esSV%+ and shSV%+ is less than I’d expect, I wonder if this is evidence that they require slightly different skillsets or if it’s just the high variance of the shSV%+.

There’s evidence to support the notion that playing short-handed is a skill. If teams share duties equally between two goalies that are generally "average" but give differing short-handed performances, we might suggest that there is something different about the skills or concentration required for short-handed play. Certainly the quality of the team’s penalty kill is also important, and it's possible that such irregularities are due to chance or other variables.

As revealed by the chart below, in 2011-12 Dubnyk and Kabibulin had wildly different shSV%+ on a team with a decent PK% (83.4%, 9th overall). Interactive chart may be viewed here.

dubnyk_khabibulin_zps735134ca.0.png

Dubnyk's performance in the lock-out year was excellent. He was an above-average goalie with a very good shSV%+. This is the kind of performance that a young team needs, a stable goaltender who can pull one out of the fire now and again. It might be less damaging than a performance that's above-average during even-strength play, but below average when the team needs the keeper to make a stop short-handed (i.e. Khabibulin 2012-13).

Note that during the lockout year many of our finest goalies, goalies who during the previous season were prominent in the top-right quadrant, were only average when it came to short-handed play (Lundqvist, Quick, Smith, for example).

To really provide a measure of "pulling one out of the fire" what is required is "SV%+ close". Perhaps such a beast will exist in the near future.

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