February 3, 2007

Goaltender win statistic

Winning is the most important statistic for a goaltender in hockey. However, due to the fact that different teams win at different rates. Many teams could win with a terrible goaltender and the goaltender they use often gets a great win record (Cloutier, Theodore anyone). A great save percentage or GAA is worthless if it doesn't result in more wins. However you can calculate the likelihood of winning with a normal goaltender using a Pythagorean prediction: GF2/(GF2 + GA2), where GF = goaltender teams' scoring and GA = expected goals against. So if you score 3 and there are 2.8 expected goals against your goaltender: 32/(32 + 2.82) = 53%. If a goaltender looses a game when his team gets 7 goals for and there are the average 2.8 expected goals against: 72/(72 + 2.82) = 86%. Now if you sum up all those probabilities for any given goaltender then you get the number of expected wins. Then you just compare to the actual number of wins (I converted SOW/SOL to T and OTL to L). The difference between actual and expected gives you an idea how many extra wins a goalie is providing. However I wanted to scale out games played, so I divided by games played and multiplied by 60 (starting goaltender games per season), so that the W+ number represents the number of additional wins this goalie provides in the season where they play 60 games. A goalie like Luongo/Brodeur will play 70+ games so the numbers aren't perfect, but they're good enough.
W+ =60* (actual wins - expected wins)/GP
Here's the list [GP>10]:
NlastnamestatGPActualExpected
1HUET7.91331915
2GIGUERE7.72342622
3LUONGO6.17482824
4MASON6.08312017
5BRODEUR4.63503127
6EMERY4.28352119
7TURCO3.50442421
8HASEK3.44382725
9LEGACE3.33351615
10TOSKALA3.17292120
11NABOKOV3.17231211
12BACKSTROM3.081466
13NORRENA2.97271413
14VOKOUN2.56221414
15LEHTONEN2.50452220
16FLEURY2.28412322
17TELLQVIST1.761688
18KIPRUSOFF1.57462625
19BELFOUR1.54281414
20AEBISCHER1.301999
21WARD1.21402322
22RAYCROFT1.15432423
23FERNANDEZ0.77391918
24MILLER0.72372121
25KHABIBULIN0.54361818
26JOSEPH0.50301212
27DIPIETRO0.43391919
28JOHNSON0.281455
29BIRON0.20161111
30KOLZIG0.10381818
31THOMAS0.08381818
32LUNDQVIST-0.22391819
33DUNHAM-0.251244
34HOLMQVIST-0.75271515
35GRAHAME-0.791455
36ESCHE-1.011456
37BUDAJ-1.50301516
38ROLOSON-1.61442022
39TOIVONEN-1.901133
40SANFORD-3.681134
41LECLAIRE-4.532068
42GERBER-5.1218810
43BRYZGALOV-6.121467
44THEODORE-6.2821811
45GARON-6.3318810
46AULD-6.4425811
47Boucher-6.871424
48WEEKES-7.531246
49CLOUTIER-7.912269
50NIITTYMAKI-8.1737813
51DENIS-8.82261014


It should be noted that luck plays a bigger part in these statistics as there aren't many events (<50), these results could be interpreted as random, however the list is a good representation of how man goaltenders on this list have played. I'll try going back a few season later on to see what happens when I include more data.

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