All hail, the “Kuemperor”!!
Well, let’s not get ahead of ourselves. First things first.
As we begin to settle in and get adjusted to the Washington Capitals newly reshaped roster, we can begin to analyze the projected affects of the recent changes made. One area of focus will be the completely overhauled goaltending tandem of Darcy Kuemper and Charlie Lindgren. First up, the new starter, Darcy Kuemper.
[As always, we first want to thank all the fine folks at Natural Stat Trick, Evolving Hockey, HockeyViz, and Hockey Reference for the data utilized in our analysis. To learn more about the statistical terms used in this post, please check out our NHL Analytics Glossary.]
With that, let’s get to it.
Games Played And Goals Differential
As we begin to dig deeper on Darcy, (or any goalie for that matter) one of the first advanced stats we typically look at is the Goals Saved Above Expected, or Goals Differential. It’s simply the difference between expected goals and actual goals. (xGA – GA).
For those not familiar with the term “expected goals”, a brief primer. The value is based on an advanced statistical model that utilizes historical shot data (shot type, location, result, etc.) to generate an “expected goals” percentage for each and every shot in a game.
A simplified example. If a slap shot from the right faceoff dot (or any exact location) historically scores 5% of the time, then any shot in a game of that type from that location is assigned a value of .05. These values are summed for every shot in a game to determine the total “expected goals” for a team in a game.
If the total of expected goals is 2.75 for a game, but the goaltender yields just two goals in the game, the netminder earned a +.75 goals differential for the game. He gave up less than “expected”, or less than historically scored in the past.
The following graph plots the cumulative goals differential for each season in Kuemper’s career. It also includes the teams he played for and the number of games he played in each season. [Click to enlarge].
Kuemper had his second-best goals differential last season for the Stanley Cup champion Colorado Avalanche, but also played in the most games in his career. His numbers have been generally improving in recent years.
The number of games he has appeared in has also steadily increased in recent seasons, which is, overall, and encouraging trend on both fronts. Note the negative goals differential for the 2017-18 season, he only appeared in 10 games. Not a good sample size.
[Stat Note: Colorado had a pretty good defense, but the goals differential metric does a decent job of neutralizing the quality of defense when assessing goaltenders. Goaltenders will have a higher expected goals against number and higher actual goals against number on teams with poorer defenses, but the difference is the key.
As previously noted, Kuemper has been generally tracking in the positive direction since the 2017-18 season, when he was with the Los Angeles Kings. The graph below plots his general trend line.
Our analysis and assessment is just getting started, as we will next take a look at a few of the other career trends for Kuemper (and Lindgren) in the coming days. We will also begin to project differences between last years goaltenders, Vitek Vanecek and Ilya Samsonov, and the newly acquired Kuemper and Lindgren.
By Jon Sorensen