iiinova — where your digital self keeps evolving

Justin Choi @justinochoi.bsky.social · 21/09/2026

Come and work with me in the Cleveland Guardians R&D team! All backgrounds / experience levels are welcome: grnh.se/bj8qqxr42us

grnh.se

Data Scientist

Cleveland, Ohio, United States

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Justin Choi @justinochoi.bsky.social · 04/07/2026

Happy 4th! I started a blog to document the stats-related projects I do outside of work. First post is about Gaussian Processes, which are extremely cool and useful but tricky to implement: open.substack.com/pub/honestst...

open.substack.com

Implementing a Nearest-Neighbor Gaussian Process in PyMC

Not very glamorous – but I learned a lot along the way

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Justin Choi @justinochoi.bsky.social · 26/02/2026

If you're planning to be at the SABR Analytics conference, feel free to reach out so we can connect!

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Jon Bois @jonbois.bsky.social · 09/02/2026

so far tonight bad bunny has sung more reggaeton songs than the patriots and seahawks combined

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Justin Choi @justinochoi.bsky.social · 26/01/2026

I rarely watch football, how common are penalties for unsportsmanlike conduct??

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Solomon Kurz @solomonkurz.bsky.social · 14/01/2026

The 0.5.0 version of my {brms} + {tidyverse} translation of McElreath's "Statistical Rethinking" (2nd ed) is up! solomon.quarto.pub/sr2/ 1/3 #rstats

solomon.quarto.pub

Statistical rethinking 2 with rstan and the tidyverse

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Justin Choi @justinochoi.bsky.social · 12/01/2026

I wasn't able to contribute this year, but I'm definitely putting in an order – and I highly recommend that you do the same!

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Stephen Sutton-Brown @srbrown70.bsky.social · 08/01/2026

"The result isn’t optimization, it’s about survival" Really enjoyed working on this piece with @jrodrigues39.bsky.social on how swings age, building off work from @justinochoi.bsky.social. Link to the code behind it below! www.baseballprospectus.com/news/article...

baseballprospectus.com

Under the Hood of The Aging Hitter | Baseball Prospectus

As always, there are hidden taxes.

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Sky Kalkman @skykalkman.bsky.social · 02/01/2026

Hi, BlueSky converts. Probably deserves some updating, but here's a list of baseball analytics nerds if that's up your alley. go.bsky.app/GZjLuxK

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Patrick Dubuque @euqubud.baseballprospectus.com · 17/11/2025

Hey, SABR hasn't put both its feet into bluesky yet (I know, a lot of its people have) but this is a good time to remind you that the SABR Analytics Conference Research Awards are open for nominations. When you have a few minutes, please nominate some of your favorite baseball research from 2025.

sabr.org

Seeking nominations for 2026 SABR Analytics Conference Research Awards – Society for American Baseball Research

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Bradley Woodrum @bradleywoodrum.com · 02/11/2025

The code is all here! The raw data is masked, as that is proprietary @baseballprospectus.com data. But BP subscribers should be able to access the same data via the leaderboards to recreate a Fully Operational simulation: github.com/bwoodrum3/ws...

github.com

GitHub - bwoodrum3/ws_2025_monte_carlo: A Monte Carlo simulation of the 2025 MLB World Series using PECOTA probabilities.

A Monte Carlo simulation of the 2025 MLB World Series using PECOTA probabilities. - bwoodrum3/ws_2025_monte_carlo

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Justin Choi @justinochoi.bsky.social · 01/11/2025

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:

Bat speed aging curve comparing two methods, one with no correction for age and another that corrects for age (fewer younger players and older players)

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Brent Maguire @bmags94.bsky.social · 01/11/2025

Game 6 ends on a game-winning double play. The Dodgers managed to escape the ninth inning and force a Game 7. Incredible stuff.

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Justin Choi @justinochoi.bsky.social · 20/10/2025

Is AWS being down an omen about the fate of the Mariners

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Justin Choi @justinochoi.bsky.social · 15/10/2025

Alright third of the way there, keep it up boys

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Dr. Meredith Wills ⚾️⚾️👀 @bbl-astrophyscs.bsky.social · 14/10/2025

Gotta give props to last year’s #SMTDataChallenge winners, who created the Snell Tool (snelltool.com), which tells when to pull the starting pitcher. Tried it with Snell just now, and it said to pull him after the 8th. Looks like Dave Roberts agrees!

Game state when Sal Frelick came up B8, which says to keep Snell in.

Game state at the end of the inning, which says to pull Snell.

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Justin Choi @justinochoi.bsky.social · 14/10/2025

Yeah just gonna need Yamamoto, Ohtani, and Glasnow to throw CGSOs. Thanks

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Umair Durrani @transport-talk.bsky.social · 25/09/2025

{gm} - Create music with R: flujoo.github.io/gm/ #RStats bookmark from old twitter

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datawithbliss.bsky.social @datawithbliss.bsky.social · 25/09/2025

The 2026 Big Data Bowl #BigDataBowl is live! Participants can sign up for two competitions: - leaderboard - traditional analytics competition This year's task: predict/understand player movement when the ball is in the air

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Brent Maguire @bmags94.bsky.social · 25/09/2025

60 home runs for Cal Raleigh. Incredible.

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Stephen Sutton-Brown @srbrown70.bsky.social · 22/09/2025

Why did Luis García Jr. get fooled so badly on this pitch? In my article representation of my SaberSeminar presentation, I answer just that and explain how visual uncertainty influences pitch tracking and helps to explain swings. Link below. www.mlb.com/video/luis-g...

mlb.com

Luis García Jr. strikes out swinging. | 08/08/2024

Luis García Jr. strikes out swinging.

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Justin Choi @justinochoi.bsky.social · 16/09/2025

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:

An example of the "generalized" dynamic dead zone, using Edwin Diaz's 2024 sliders. There are contour plots of his actual slider movement, conditional movement given release characteristics using the DDZ method, and the same thing, but with the GDDZ.

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Ben Clemens @benclemens.bsky.social · 16/09/2025

Every so often we check in on the models

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Gabe Schumm, Ph.D. @stripester.bsky.social · 06/09/2025

Induced vertical break, spin efficiency, seam-shifted wake—what do these buzzwords mean for a pitch trajectory? Explore using my Statcast-based pitch visualizer (physics modeling based on work of @pobguy.bsky.social). Updated daily with new pitching data! gabes135.github.io/pitch-graphic/

gabes135.github.io

Pitch Visualizer

Computational Physics Ph.D.

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Sam Miller @sammillerbb.bsky.social · 07/09/2025

Cal Ripken Jr has missed 3,765 consecutive games

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Justin Choi @justinochoi.bsky.social · 24/08/2025

Alright, I've tidied up the repo and added my presentation. Thank you to everyone who was at @saberseminar.bsky.social yesterday! Was a pleasure to meet so many bright and interesting people. github.com/justinochoi/...

github.com

GitHub - justinochoi/SaberSeminar2025

Contribute to justinochoi/SaberSeminar2025 development by creating an account on GitHub.

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Justin Choi @justinochoi.bsky.social · 22/08/2025

You don't truly appreciate how fast Korea's wifi is until you're standing in an endless line for border control at O'Hare

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🪩 Kiri 🪩 @kirio.bsky.social · 20/08/2025

I really enjoyed chatting with Hannah about the ups and downs of working in baseball -- and my decision to not do that anymore.

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Stephen Nelson @stephennelson.bsky.social · 18/08/2025

Welp, here’s the dumbest #BoothViews I’ve ever done. Here’s how it played out as my voice gave out ending today’s broadcast 🫠😂 glad Bulldog got a kick out of it!

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Jonathan Judge @bachlaw.bsky.social · 17/08/2025

America needs one of those language authorities like the French have so every person who spells it “woah” is immediately arrested.

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Justin Choi @justinochoi.bsky.social · 13/08/2025

Slightly diminish a band The Lice

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Justin Choi @justinochoi.bsky.social · 10/08/2025

Coming soon to a saberseminar near you: hydrogen bomb vs. coughing baby

Simulated distribution of Tarik Skubal's four in an 0-2 count, and his predicted run value per 100 against a lefty Dylan Carlson

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Justin Choi @justinochoi.bsky.social · 08/08/2025

I've never ran away so fast from a job posting until now

Job posting says "this is not an opportunity to focus on work life balance"

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The Onion @theonion.com · 07/08/2025

Sleeping Man Flanked By Laptop, Phone, Earbuds Like Egyptian Pharaoh Buried With All His Treasures

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Mark Zuckerman @markzuckerman.bsky.social · 06/08/2025

Cade Cavalli's 1st inning back in the majors: 1-2-3 with 2 strikeouts on 13 pitches. Fastball was 97-100 and sharp. Curveball was 88. Changeup was 91. Couldn't have drawn that up any better.

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Justin Choi @justinochoi.bsky.social · 01/08/2025

"prompt engineering" is still one of dumbest phrases i've heard in my life

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National Baseball Hall of Fame and Museum @baseballhall.org · 27/07/2025

Welcome to baseball immortality, Ichiro Suzuki.

ICHIRO SUZUKI

Seattle, A.L. 2001-12, 2018-19; New York, A.L. 2012-14;

Miami, N.L. 2015-17

With extraordinary work ethic and unparalleled bat control, brought record-setting hit totals to Major League Baseball as its first Japanese-born position player. Electrified 2001 Mariners to record 116-win campaign, earning A.L. Rookie of the Year and Most Valuable Player honors. The only player with 10 straight 200-hit campaigns, 2001-2010, set all-time single-season hits record with 262 in 2004. An All-Star and Gold Glove outfielder throughout his first decade in the majors, led A.L. in hits seven times. Won two A.L. batting titles after capturing seven consecutive in Japan. Totaled 3,089 MLB hits and 509 stolen bases.

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Photo: Milo Stewart Jr./National Baseball Hall of Fame and Museum

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CJ Fogler @cjzero.bsky.social · 27/07/2025

"3000 hits or 262 hits in one season are achievements recognized by the writers, well, all but one of you" Ichiro Suzuki

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Saberseminar @saberseminar.bsky.social · 20/07/2025

We have our first NPB team sponsoring Saberseminar this year--the Chiba Lotte Marines. They'll also be giving a talk about NPB and how the league is different from MLB. Really excited for this one! Reminder that ticket sales and sponsorships are still available here: www.saberseminar.com

saberseminar.com

Sabermetrics Scouting and the Science of Baseball

A Weekend Baseball Seminar for the Benefit of The Angioma Alliance

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The Onion @theonion.com · 10/07/2025

Study: 97% Of Average American’s Day Spent Retrieving 6-Digit Codes theonion.com/study-9...

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lindsey adler @lindseyadler.bsky.social · 08/07/2025

This is a cringey thing to do but I am looking for a publication that would like a nice big piece on Oasis from someone who has a deep knowledge of the band, their subculture, and is attending two of their hometown shows (me). I also have a lot of thoughts about commercialism in music. Thanks!

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MLB @mlbbot.bsky.social · 03/07/2025

JACOB YOUNG ARE YOU KIDDING WHAT A CATCH 🤯

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Jon Becker @becker.fangraphs.com · 25/06/2025

Some personal news: I've joined @fangraphs.com full-time as an Analyst and Junior Developer! Getting paid to do what I love is an absolute treat and I'm so excited to keep working on RosterResource, write the occasional payroll wonk article, and help the dev side with new features!

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