Pitcher Accuracy Through Catcher Spotting: Assessing Rater Reliability

Pitcher intent, as measured by the position of the catcher's glove before a pitch is thrown, is an element of baseball that is regularly observed by commentators ("he's missing his spots") but remains an uncaptured aspect of statistical analysis of the game, offering many potential aspects on pitcher performance that have yet to be exploited. In order to collect this data systematically for public consumption (a far from trivial task), I propose and design a number of mechanisms for manual collection of this data from video playback using an offine charting approach, the direct indication of catcher position on the video, or a combination of the two. Through a pilot study conducted via a web applet, I find that there are considerable advantages to the direct-on-video method of charting catcher spots, including a higher inter-rater reliability as a consequence of higher precision and fewer replays needed of each pitch for a measurement to be taken, suggesting that direct video analysis, rather than lower-tech zone assessment, will be the preferred method for collecting catcher spotting data as the method becomes more popular.