Advanced Statistics for Beginners: Goals Versus ThresholdPosted: 12/01/2013
Here we are at the second of a four part series, you can read the introduction here. For a much more in-depth explanation of this methodology, please check out PuckProspectus.com, or Faceoff-Factor.com for some high end stats use applied directly to the Pens.
Perhaps the single most invaluable statistic for any sport is the relative value of a starting player over his (or her) replacement. In baseball this statistic is known as VORP, Value Over Replacement Player, and essentially in both hockey and baseball it tabulates how much a given player contributes compared to a fictitious, replacement player: in GVT this player is equivalent to the league average productivity of all players at a certain position (which is different from baseball which assumes comparable defense to the starter, but worse offense). As Tom Awad, the creator of GVT asserts, “GVT… is calculated in goals. This is fundamental: goals, not wins, are the basic building blocks of hockey games.” Basically, it’s only by scoring goals and preventing goals that your team actually earns a win, and as such your ability to contribute to that measure sets you above or below the average.
GVT can be divided into 4 different categories, Offensive GVT, Defensive GVT, Goaltending GVT, and Shootout GVT. Below is the super brief synopsis of each measurement.
“Offensive GVT is extremely straightforward: it measures a player’s contribution to scoring goals. Offensive GVT is based on goals and assists scored above what a replacement-level player would have done with the same ice time.”
Defensive GVT “defines the defense’s job as preventing shots on goal…GVT factors in the number of shots allowed by a player’s team, his plus/minus, and his penalty killing ice time to obtain his defensive GVT.”
Goaltending GVT “defines the goaltender’s job as stopping shots…Goaltending GVT [is] relatively easy to calculate: it is simply the expected number of ogals allowed, given the number of shots face, minus the actual number of goals allowed by the goaltender. As a nod to shot quality effects, the goaltender is only credited for 75% of the extra saves performed, while the defense gets the credit for the remaining 25%.”
“Shootout GVT simply measures whether a player was good at capitalizing on his shootout chances, or preventing them if he is the goalie.” (all quotes from Tom Awad in his “The Essential Guide to the 2012-2013 NHL Season: Hockey Prospectus 2012-13”)
Although this might seem ridiculously complex all you really need to take away is that any player with a positive GVT is a better than “average” player, and anyone with a negative number is not. For example, Geno’s GVT from last year was 27.8 or in other words his measurable statistics are almost 28 times better than the league average. That’s probably why he is the league’s reigning scoring champ and MVP. To show you a little bit more about how GVT evaluates a player’s overall effectiveness we will also examine James Neal’s GVT now. Despite finishing 7th in the league in scoring and 4th in goals Neal only pulled off a 19.0 GVT, good for 23rd in the league (and third on the team behind Pascal Dupuis). You might ask why his number would be so much lower than Geno’s and the answer is simple: the two things that Neal still needs to work on—taking bad, offensive zone penalties, and overall defense—hurt his final score, as such, we can see how much better Geno is than Neal just by looking at GVT stats.
Overall the Penguins were the number 2 GVT team in the league last year and no guaranteed starter (except for Tanner Glass, who wasn’t in Pittsburgh last year, and who finished a whopping -0.1) earned a net negative GVT, although many of the call-ups did finish with net negative scores. That is actually a really impressive statistic, every Penguin player was essentially above average at his job, no easy feat.