Sullivan: Pitch-framing data is going insane

From Jeff Sullivan at FanGraphs on November 8, 2017:

The season’s complete, which means the numbers are official. This is convenient for a writer, because it means there shouldn’t be any issues anymore with comparing 2017 to another full season in the past. A full season is a full season. So how about a quick full-season review of the pitch-framing data? There’s something interesting going on. Something dramatic, something that shakes the foundation of the numbers themselves. I have the graphs to prove it.

The most advanced pitch-framing information is available at Baseball Prospectus. It’s long been the gold standard, and so many hundreds of hours have gone into generating the results that get published on the sortable leaderboards. There are two framing metrics of note, for catchers and for entire teams. One is just framing runs above average, which is self-explanatory. The other is CSAA, or called strikes above average. This is directly related to framing runs above average, but it’s expressed as a rate stat. I think that’s all you need to know. In this post, I’m going to use them both.

There exist 10 years of detailed information, based on the pitch-tracking technology that’s been in existence. This is a plot of standard deviations, year to year, over the course of the decade. This is on the team level, using runs above average. This is just an examination of each year’s spread.

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Originally published: November 8, 2017. Last Updated: November 8, 2017.