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Marchi: Catcher framing before PITCHf/x

From Max Marchi at Baseball Prospectus on May 16, 2013:

Analysis of framing has intensified over the past couple of years, with Joe Maddon talking about it on the radio and (via Ben Lindbergh) Clubhouse Confidential and MLB Network’s Diamond Demo series featuring discussions of the issue with guests like Jonathan Lucroy. Ben has been running a weekly column on the subject since the start of the season: in the first installment (as well as this piece for Grantland) he provided some background on the research so far, so you’re invited to have a look at that article before you read the rest of this one.

Framing evaluation is one of those research subjects that has been made possible by PITCHf/x data, which means that we’re now into the sixth full season for which catcher framing can be measured. However, for quite some time, I’ve been thinking about this: if one could get a good approximation of the framing numbers just using Retrosheet pitch sequences, 20 years of catcher framing could be added to the discussion. When Ben jogged my memory recently, I decided it was time to stop thinking about it and start doing some number-crunching.

The Method
Going back to 1988, Retrosheet has data with a fair degree of completeness for pitch sequences, indicating the outcome (ball, called strike, swinging strike, foul, and so on) of every pitch thrown.

For each plate appearance, I counted the number of pitches not featuring a swing by the batter (basically balls and called strikes), with the useful Chadwick Tools saving me a lot of time and work.

In the original model I created with PITCHf/x data, in addition to using the location coordinates as measured by the camera system and the pitch type as classified by the MLBAM algorithm, I controlled for the effect of the ball/strike count, the home plate umpire, the pitcher, and the batter—plus, obviously, the catcher.

Read the full article here: http://www.baseballprospectus.com/article.php?articleid=20596

This page was last updated May 16, 2013 at 12:09 pm MST.

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