When the Ray Emery signing was announced, I breathed a sigh of relief. The Flyers had a legitimate, if unspectacular goalie in the fold, and I no longer needed to fear that Steve Mason would get 60 starts next year.
Even strength save percentage is my preferred metric for comparing goalies. Of the 50 active goalies who have faced at least 2000 even strength shots, Mason ranked a putrid 44th (ahead of only DiPietro, MacDonald, Hedberg, Boucher, Leighton, and Gustavsson), while Emery was a more passable 30th. That had cemented in my head the sense that one was a poor-but-passable starter and the other was a reject, but when I looked more closely at their numbers, the gap between them wasn't as large as I'd imagined.
In the table below, you can see the career stats for each goalie. The columns in the middle -- save percentage -- are how they performed, while the shots faced columns are there to give an indication of the sample sizes.
|Mason shots faced||Mason save%||Emery save%||Emery shots faced|
Emery has been better, but the difference really isn't very large -- something like four saves per thousand shots. When we're talking about sample sizes of only a few thousand shots, it's easy to see a difference that large just by random chance.
In fact, given two exactly equal goalies, the odds of seeing a difference of this size in their even strength save percentage is 32.7%. Before we look any deeper, there's nearly a one-in-three chance that Mason is actually a better goalie than Emery. And if each is in net for 1000 shots this year, it's a virtual toss-up which goalie would perform better.
Of course, while I tend to write mostly about the numbers because that's where my expertise lies, I recognize that they don't tell the whole story. Perhaps Emery's injuries have suppressed his career numbers, and the stronger performances in his up-and-down record give a better indication of his potential when healthy -- and maybe his career dating back to an era of lower save percentages is making him look a bit worse. On the flip side, perhaps Mason's youth means that he is still developing and that we should expect more out of him as he enters his prime than what he's shown through his early 20's.
The relatively small samples we have for each goalie leaves a lot of uncertainty in the numbers -- there is room for us to inject a lot of opinion, and a fair case can be made either way. We just don't know a goalie's talent all that precisely after 6000 shots.
It's unlikely that either goalie is as good as the average NHL starter (typically ~.923 even strength save percentage), but it's certainly not impossible. If I have to place a bet on who the better goalie is, I'm betting on Emery, but I'm giving Mason a much better chance than I thought he'd have.