By JASON LOWENTHAL
Our second installment of advanced statistics focuses on
goalies. In basic hockey stats, we use wins, goals against average, and save
percentage as baseline metrics to value a goaltender. Today we take a look at
more advanced goaltending metrics; quality starts, quality start percentage and
goaltender steals.
A quality start, as defined by Hockey Prospectus, is a
statistic used to measure whether a goaltender “gave his team a chance to win.”
Hockey Prospectus also acknowledges that this statistic is directly borrowed
from the game of baseball for pitchers. To determine whether a goalie’s effort
was worthy of a quality start, his stat line must land within one of the
following options:
· Allowed two goals or less AND save percentage of at least .844
·
Allowed three
or more goals AND save percentage of at least .911
Let’s apply this to a couple games from last season so we
can see the difference between a quality start and a non-quality start. In the
season opener last year against Green Bay, Steel goaltender Chris Nell
surrendered five goals on 34 shots. So, we look at our options and determine
that Nell must have recorded a save percentage of at least .911 for his effort
to be determined as a quality start. However, his save percentage for the game
was only .853. Thus, this was not a quality start in the season opener. Now
look at his next performance. The following day against Waterloo, Nell was back
in net and he allowed three goals on 41 shots. Again, we look to the second
option because he allowed three goals. However, this time, his save percentage
was .927. Because .927 is larger than .911, this qualified as a quality start
for Nell. One important note is that even though the Steel lost this game to
Waterloo by a score of 3-2, a quality start was still recorded. The outcome of
the game has no effect on determining whether a start is considered quality or
not.
Through the course of the season, Nell started 40 games. In
those starts, 20 were quality, giving Nell a quality start percentage of .500
for the season. His backup, Cale Morris, started the remaining 20 games and
recorded 11 quality starts, giving him a quality start percentage .550. Morris’
quality start percentage was slightly higher than Nell’s last season, but Nell
started in net more often. A quality start percentage of .600 is considered
very good for a goaltender and a quality start percentage of .400 is poor.
Therefore, Morris is placed in the upper echelon of goaltenders in terms of quality
start percentage while Nell is considered more average, in the middle.
Essentially, quality start percentage gives value to the
percentage of games started in which the goaltender kept his team in the game.
It can also be used as a measure of consistency for a goaltender.
The other advanced goaltending statistic we will take a look
at it goalie steals, defined as a game in which the goalie surrenders one goal
or less while facing at least 35 shots.
Last season, Nell was awarded with four goalie steals. His
most impressive performance statistically came in a 3-0 shutout of Fargo when he
turned away all 40 shots. Morris failed to qualify for a goalie steal last season.
Obviously, the problem with goalie steals is that it cannot
be used as a measure of consistency. Therefore it does not have as much
validity as quality start percentage. However, it still has some value as a
measure of the amount of games that the goalie single-handedly kept his team in
(stole). Typically, this comes in a victory, although it does not have to. For
instance, Nell recorded a goalie steal in a 1-0 loss to Dubuque last year when
he stopped 34 of 35 shots.
Be sure to check out our third installment of advanced
statistics when we head back to the offensive end for a look at goals created
and points per shot attempted.
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