August 7th, 2011 by Aaron
Some minor additions to the detailed bout stats we've been developing over here, and that's the bird's-eye-view Score per Jam Charts. By framing team scores per jam in a few different ways, we can pull out some interesting bits of information.
Looking at Duke vs Bay Area from the 2009 Western Regionals. Note that for each chart, green is who ultimately won, and red is who ultimately lost. The first is Total Score per Jam:
I like to read this as the grand narrative of the bout. It's easy to see rapid advances in score, flat defensive periods, and criss-crossing lines during exciting lead changes. A glance at this describes pretty distinctly what this game was about.
Next is Total Score Margin per Jam:
This plots how far ahead a team was for each jam. Here, it's totally clear just how much of the bout Duke was ahead for -- in a way that's not nearly as obvious in the first chart.
These two charts were plotting the cumulative score over time. The next two plot the individual scores of each jam. Here's Score per Jam:
This is simply showing how many points were scored by each team per jam. Reading this is helpful for pulling out high scoring, game changing jams.
And finally, Score Margin per Jam:
This chart plots the difference between both scores per jam. Since points scored by the opposing team reduce a team's scoring power, this chart represents the effective gain for a team. By flipping between this chart and the last, you can see where jams disappear because equal efforts by both team's cancelled each other out. Of course this is undesirable in roller derby, and we only see the effect of this normalization in a handful of jams.
Lot's more stuff to come. You can see more bouts like this in the 2009 Western Regionals. We'll be importing a lot more of your bout data soon, but we need you to send it in!
