Sunday, August 09, 2020
DER and BABIP tweetstorm
This was a tweetstorm from a few days ago.
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Since start of 2020 season, fielders have converted into outs 71.1% of the 7630 balls of hit into play
In 2019, there was NO STRETCH where fielders converted as many plays into outs. The average was 69.1%
2020 is 3.8 standard deviations from 2019
DER is essentially 1 - BABIP
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We are talking 2019 to 2020. I don’t know what level of talent influx you can have in the offseason that is targetted to fielding.
Fielding alignment might be one reason.
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It’s not just a 2019-20 difference. This is consistent back to 2016 (and earlier).
HR rates are no different in 2020 than in 2016-19:
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Those that have “angle” in it is using tracked data. The remaining (editor’s note: which is very very limited in 2020) is using stringer data. The tracked and untracked data will be biased, so be careful in making too strong a conclusion.
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From 2010-2019, the DER for SP was .691, the same as for RP.
In 2020:
.718 SP
.703 RP
So, Starting Pitchers are driving the big change
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This shows how often balls assigned to outfielders are converted into outs.
It removes balls assigned to infielders as well as any "impossible to make" plays. As you can see, a slightly more number of plays being made by outfielders meaning slightly better positioning, or balls luckily getting closer to the outfielders. This is only one standard deviation, so, not THAT much of an impact. And since it's a different tracking software, it could be slightly different as a result.
So, probably not due to OF positioning.