I recently wrote an article about Todd Frazier’s stolen bases for BP Southside, the Baseball Prospectus White Sox site, and in doing so did a decent amount of digging into the different advanced measures of base-stealing productivity—something that would take into account all the necessary components and spit out a measure of runs saved or lost. I got frustrated by a few things, and so decided to type this up, as I think it encapsulates a lot of issues in public sports analysis. All of this is written from a baseball perspective, but it applies at least as much to hockey and probably even more to basketball.

Before I start I want to say that the various sports stats sites strike me in many ways as emblematic of the promise of the internet. Vast amounts of cross-indexed information that can be used with minimal technical abilities, and synthesizing months and years of work done often…