Posted by Mike on October 9, 2013
Today on Hockey Reference we're rolling out two new stats for goalie pages: Adjusted Save Percentage (SV%+) and Goals Saved Above Average (GSAA). First, you can check Broad Street Hockey for a great explanation of adjusted save percentage and goals saved, but for a simple look, consider the 2012-13 NHL season. League-wide, there were 41,827 shots overall and 3,684 goals scored, for a goals against average of 8.81%. Vezina Trophy winner Sergei Bobrovsky had a goals against average of 6.87% -- 29% better than league average, giving him a SV%+ of 129. Taking that 29% better performance into account combined with the number of shots he faced, we say he saved 21.48 goals more than an average goalie would have, given equal playing time.
These stats are especially helpful for comparing goalies across eras: Patrick Roy led the league in save percentage in the 1991-92 season with a .914 SV%; in the 2012-2013 season that would have placed him as the 26th best goalie between Ben Scrivens and Jonas Hiller. However, we can look at his SV%+ of 130 for that year and see that he was actually 30% better than the league average at stopping goals -- better than Bobrovsky, even.
Note that SV%+ has a minimum requirement of 4 shots faced per team game, so that we don't have goalies who stopped 7 of 7 shots faced in their single period played skewing the results. These stats are now up for goalies as far back as the 1983-84 season (the first year we have shots against data for the NHL), and for the entirety of the WHA (1972-1979), and will be updated throughout the year.