Advanced Statistics for Beginners: Player Usage ChartsPosted: 12/01/2013
Here we are at the final installment of a four part series, you can read the introduction here, part 2 here, and part 3 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.
Before fully exploring the charts themselves we must first introduce the three elements that make the chart: Corsi Numbers, Quality of Competition, and Offensive Zone Start %. To quote Timo Seppa and Robert Vollman, the editors at PuckProspectus.com, “Corsi (another poorly-named statistic) is simply a player’s plus/minus, except that it’s measured in attempted shots instead of goals.” In other words, it looks at a player’s effectiveness every shift instead of only the shifts when he happens to be on the ice for a goal. This stat much more accurately represents the overall flow of any specific game and any specific shift. A high positive Corsi Number indicates that a player tends to be on the ice for a lot of offensive, puck control time, whereas a low or negative Corsi Number would indicate a player stuck with the tough task of defending the opposing team’s best players as they control play in your zone.
When Corsi numbers are compared to Quality of Competition stats, we can begin to see how coveted defensive zone specialists are. Again to quote Seppa and Vollman, “‘Quality of Competition’ is the average plus/minus of a player’s opponents over 60 minutes at even strength, except that it is based on [Corsi Scores] instead of goals.” In other words, teams always try to create favorable matchups against their opponents, if the other team has weak defenders on the ice, a good coach will often try to put his best offensive players against them, and that same coach will try to match his best defenders against the opponent’s best scorers. This is why home ice advantage can be so important in the playoffs: home teams get the last change: they can always choose who to send out on the ice (except in icing situations) and thus have the final say in balancing Quality of Competition in their team’s favor.
The final component of the chart is Offensive Zone Start %, which is “the percentage of all non-neutral zone, even strength shifts started in the offensive zone.” In other words, this stat determines whether a player is “given” the opportunity to create offense, or whether they have to fight for the puck in their own zone in order to create their own offense. When you start in your own offensive zone, you tend to have the opportunity to build a greater positive Corsi score, when you start in your own defensive zone, you tend to have a negative Corsi score.
Now that all of that has been explained, a Player Usage Chart can be assembled using all three components. Each individual player is represented by a “Corsi Bubble,” the coloring of the bubble (white or gray) establishes whether the player had a positive Corsi score (white) or negative (gray). The size of the bubble expresses whether that player was outshot by a large margin (big bubble) or by a small margin (small bubble). The horizontal axis represents the Offensive Zone Start % stat: a high horizontal position means you started most of your shifts in the offensive zone, whereas a low number represents a lot of defensive zone starts. The vertical axis represents Quality of Competition, a high vertical score represents good competition, whereas a low or negative score represents easy competition.
The following image is a very easy to understand representation of what the Player Usage Chart represents:
Guys like Jordan Staal, and now Brandon Sutter, would be in the top left quadrant, while if things are going well Sid, Geno, Neal and the other scorers should be on the far right corner, the closer they are to the midpoint the better Bylsma and the other Pens coaches have been at getting them out in favorable matchups. On the negative side of the vertical axis on the left hand side would be 4th liners, guys who aren’t tasked with the hardest checking assignments, but who don’t contribute much offensively. Being on the right side of the graph with a negative vertical score indicates that you are probably young—your coach sends you out only for offensive zone face-offs, and the opposing coach can’t be bothered to defend you with his best guys. Last year Simon Despres and Eric Tangradi earned this distinction for the Pens—this makes sense given that the organization has high hopes for them and wanted to give them favorable playing time.
I hope you’ve enjoyed our little tutorial, and because you’ve been so patient, here is the official chart from the Penguins from last year:
One week til game time. You ready now?