Judge: The siren song of Statcast’s ‘expected’ metrics for pitchers

From SABR member Jonathan Judge at Baseball Prospectus on May 18, 2018:

Have you heard about the new Statcast “X” metrics put out by MLB Advanced Media (MLBAM or BAM)? I’ll bet you have. In fact, I’ll bet you read about them all the time, in part because BAM strongly promotes them in its media operations.

Bloggers, columnists, and broadcasters have picked up on this encouragement, using these metrics to highlight pitchers who have been “unlucky” and others who seem poised for a “breakout” season. These takes assume that new metrics like “expected Batting Average” (xBA) and “expected weighted On-Base Average” (xwOBA) offer new and unique insights on true player performance. But is that notion supported by the data?

BAM contends that these metrics add value due to their incorporation of measurements like batted ball exit velocity and launch angle.

Read the full article here: https://www.baseballprospectus.com/news/article/40026/prospectus-feature-siren-song-statcasts-expected-metrics/

Originally published: May 18, 2018. Last Updated: May 18, 2018.