SprawlBall Takeaways
My notes as I read
SprawlBall by Kirk Goldsberry is an artful visual account of how the NBA has been impacted by analytics over the years. Providing detailed, well-explained conclusions bolstered by spatial data visualizations, this book does a great job to accomodate readers of all levels of analytical experience. After reading Astroball, this seemed like required reading to become more familiar with the intersection of my professional and personal passions.
We begin by taking a look at the strategic innovation that is most obvious to the average NBA fan, modern teams love to shoot three-pointers. This is justified to the reader using the Points Per Shot metric to highlight the drastic increase in value as you take a step over the three point line, jumping from under .85 to as high as 1.2 Points Per Shot. In simple terms, the ongoing death of the mid-range shot is not without good reason. As players became more and more capable of hitting threes over the years, strategy evolved to manufacture as many 3-point opportunites as possible. MoreyBall budded from this semantic shift of a good basketball shot, seeing a Houston offense spearheaded by Harden that would drive-and-kick to three-point shooters at a historic rate.
As is true with most analytical innovations, this strategic evolution was enable by increased data collection, with the NBA beginning to reliably record (x,y) coordinate data for every in-game shot starting in the early 2000s. Scorebooks now had a spatial element to them that could assist in shot mapping such as a player's Hot Zones as we know them today. Using a season's worth of shot data and statistical smoothing tricks you can produce a mapping of expected percentages for spatial patches in the halfcourt. While the size of the patches rely on your smoothing parameters, the author's smoothing showed little impact from distance on 2-point shot percentages. Knowing now that shot distance has middling effects on field goal percentage outside of 6 feet, why would a team like the Rockets not make it their goal to shot as many threes as possible.
To be continued