Justin Choi
justinochoi.bsky.social
Justin Choi
@justinochoi.bsky.social
Baseball research! Bylines: FanGraphs, Baseball Prospectus. Former Nationals R&D.
Bat speed aging curve, but this time I account for the fact that we are less likely to observe very young/old players. The corrected curve declines less rapidly early and more rapidly later compared to the regular curve, which seems like the correct inference:
November 1, 2025 at 8:05 PM
Working on a "generalized" version of dynamic dead zone (DDZ) that doesn't require any assumptions about the variables' distributions. You only need to specify the covariance structure, which is Gaussian for the sake of convenience:
September 16, 2025 at 7:41 PM
Coming soon to a saberseminar near you: hydrogen bomb vs. coughing baby
August 10, 2025 at 9:52 PM
I've never ran away so fast from a job posting until now
August 8, 2025 at 2:00 AM
glory glory single-A ball
June 24, 2025 at 10:50 PM
new workplace has some nice perks
May 20, 2025 at 11:03 PM
if you know, you know
April 20, 2025 at 3:02 AM
Been working on a method that determines where pitcher should aim given stuff, command, count, batter at plate etc., hopefully in time for SaberSeminar 🤞
April 18, 2025 at 12:48 AM
mission accomplished
April 1, 2025 at 10:17 PM
Some personal news: I'll be in DC this summer as a Research & Development intern!
March 24, 2025 at 9:04 PM
alright just did the cooking equivalent of frying an egg
January 23, 2025 at 10:50 PM
I doubt this is the best approach, and for some pitchers, pitch usage doesn't seem to matter at all. But there are clear results, for example, with Logan Webb (more offspeed, less fastball = lower wOBA):
January 12, 2025 at 7:52 PM