From Adam Foster at Baseball Prospectus on June 12, 2012, with mention of SABR member Cory Schwartz and Harry Pavlidis:
Data is one of baseball’s purest byproducts. It’s interlaced with the past, present and future. It provides a platform for discussion. And just as the game has an effect on it, it has an effect on the game.
PITCHf/x data, which is part of a new breed of baseball statistics, can be intimidating and overwhelming. But thanks to amazing efforts by MLB Advanced Media, Sportvison (the creator of PITCHf/x), and a growing pool of analysts, PITCHf/x has made a mark on the game. That said, its roots are still shallow, and relatively few players, coaches and on-air personalities have fully embraced it.
MLB.com’s Gameday application delivers near-live data that includes pitch type, speed, and movement information. Pitch types are defined by mathematical models that are built around velocity, spin, and movement. It’s a constantly evolving, sophisticated system.
“When we first started doing real-time classifications, we had one generic neural net [or mathematical model] for all pitchers, but we learned pretty quickly that wouldn’t work because one pitcher’s fastball can approximate another’s changeup,” Cory Schwartz, VP of Stats for MLB.com, explained in an email. “Ultimately, we built a custom neural net for each pitcher and now have one for over 1,100 pitchers.”
In addition to rookie pitchers and their unique arsenals, MLB.com’s models must also be adjusted for pitchers introducing new pitches and tweaking others, which happens regularly. In Lincecum’s case, he cut his slider out of his arsenal for a while, and MLB.com’s mathematical model still thought it saw some.
“It’s an extremely labor-intensive process, but we recognize the importance of accurate classifications, for fans, clubs and industry partners alike, and have invested literally hundreds of man hours into building the most accurate system possible,” Schwartz wrote. “While some pitchers do throw a very distinct repertoire that can be easily classified, many throw multiple pitches that blend together and are extremely difficult to differentiate from other pitch types.”
Harry Pavlidis, founder of Pitch Info LLC, has devoted considerable time to formulating his own PITCHf/x classifications, which now appear at Brooks Baseball. Thanks to the efforts of Schwartz, Pavlidis, and others, pitch classifications have improved dramatically, and I expect them to continue to improve.
Read the full article here: http://www.baseballprospectus.com/article.php?articleid=17327
Originally published: June 12, 2012. Last Updated: June 12, 2012.