THE VALUE OF A SHUTOUT
The break point appears to be with the third goal, as all the goalies had a losing record when giving up 3 goals or more.
The results indicate that goalies who give up 2 goals or less will win 85-90% of the time.
I propose creating a stat called a “quality game” (inspired by baseball’s quality start statistic), which refers to any game where the goalie played the entire game and allowed 2 goals or less.
WHAT ARE QUALITY STARTS
Most quality start definitions include something to do with 2 goals or less, just because the winning percentage splits drop so dramatically for a team once that third goal goes in.
It is probably a good idea to look at metrics like quality starts to avoid penalizing goalies too much for a few bad games that really hurt their seasonal GAA and save percentage stats, or on the other hand to see if goalies that record a lot of shutouts are really putting up excellent performances from game-to-game.
DEFINING QUALITY STARTS
(Mar 2009)
The odds of a team winning become very high when their goalie stops a higher-than-median percentage of shots, very low when the goalie fails to stop at least 88.5% of shots, and is essentially even in the middle.
A Quality Start is defined as any start in which the goaltender’s save percentage is .913 or better, or at least 0.885 percent, but allowed fewer than 3 goals. Looking at every game this season, Quality starts have resulted in an actual winning percentage of 0.775, while non-Quality Starts have a winning percentage of only 0.325.
GAUGING GOALIE CONSISTENCY
(May 2010)
Gauging the consistency of a goalie is the primary purpose of Quality Starts.
Quality Starts, a concept borrowed from baseball analysts, tells us exactly which goalies are consistently keeping their teams in a position to win.
QUALITY STARTS (QS) AND REALLY BAD STARTS (RBS)
(Jan 2011)
Generally a team will only lose roughly 25% of the time their goalie earns a Quality Start, and likewise will somehow manage to secure the two points 25% of the time that their goalies fails.
There hasn’t been a great deal of historical persistence to Quality Starts. The list of leaders and stinkers change every year.
Really Bad Start (RBS), which is defined as any game where your starting goalie fails to stop at least 85% of the shots.
Given that the chance of winning an RBS is only 11%, you really have no choice but to gamble on your backup, so it pays to have a good one
WHAT’S A GOOD QS%
(Dec 2014)
If the starting goalie stops at least a league average number of shots in a particular game, assuming he was sufficiently tested, then that’s all that can be fairly expected of him.
Obviously, a quality start percentage (QS%) below 50% is quite poor, anything over 60% will be among the league leaders, and the average for an NHL regular is 53.4%
the average for replacement-level goalies is 42.8%
This statistic is independent of a team’s offensive and defensive abilities, and can be achieved regardless of how much goal support he received, and can be maintained even if and when he is traded to another team.
PREDICTING QS%
(Oct 27, 2016)
QS is not a very repeatable stat. It turns out that past SV% is better at predicting future QS% than past QS% is at predicting future QS%.
how good a goalie is at getting Quality Starts is mostly a result of how high his SV% is.
Quality Starts are not a repeatable skill. There is no such thing as a goalie who gives his team a chance to win more often than any other goalie with a similar SV% would be expected to do.
STEALS & QUALITY STARTS
any game where a goalie posts a goals saved above expected of at least zero is a Quality Start.
It awards a quality start to goalies who post a save percentage at least as high as the league average for that season or if they allow two goals or less and post a save percentage above that of a replacement level goalie.
A steal is any time the goalie’s goals saved above expected is greater than the final goal differential in the game.
What should be immediately clear is that these numbers don’t tell us much about who the best goalies are. If we want to know who’s playing the best over a given timeframe, we can look at goals saved above expected.
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