The Leadoff — Conventional Wisdom, Tested

Should You Burn One? A Challenge Is a Wasting Asset. Teams Hoard It Anyway.

How sure you need to be before you challenge — and why teams wait too long

ABS · 11 min read

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A polished editorial baseball analytics scene with a strike-zone study, scorebook marks, and pitch-tracking traces on a clean white desk. — Fig.1 — Called-strike rate by location
2025 baseline · inside → away

By the Numbers

Pitches analyzed

Seasons of Statcast

Umpires graded

Investigations published

The Investigations

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hitting

Where Cal Raleigh Broke — and Where He Didn't

Cal Raleigh’s 2026 collapse — a .394 wOBA to .255 — lives in the ball off the bat: about 95% of the lost run value in a model-based decomposition. What pitchers throw him accounts for roughly none of it (−4% and +6% in two independent estimates, intervals around zero), his swing decisions and miss rate for about −0.7%, and his bat speed is intact (73.1 → 72.5 mph). The pattern is consistent with a centering loss; flush contact fell from about one in seven balls to one in twenty. The one visible change in his swing — soft stuff met about 2.4 inches deeper — was already in place in late August 2025, while he was hitting .475 hard-hit, and it does not explain the loss; the IL did not start it, and the cause is not identifiable from tracking data. “They went upstairs and he’s chasing” is an artifact of the fixed 2026 ABS box. Two model families, cross-verified; sealed lines and endpoints we’ll score in October.

August 17, 2026 · 16 min read

hitting

The Book Is Good by Pitch 150. We Can't Tell You When It Was Written.

We tried to film the adjustment every broadcast narrates — the league writing its book on a rookie over his first months — and couldn't find it happening. What we found instead: a debutant's first 150 major-league pitches predict the diet he'll see a full season later at least roughly as well as an established hitter's opening week predicts his (+0.43 vs +0.39 — a comparison whose tolerance is wide, so read it as no detectable penalty rather than equality), and whatever the league settles on in those first 150 pitches is mostly still in place in September. Our reading of the 2026 class is that there's no rookie script, only hitter-by-hitter plans; and Kevin McGonigle's class-largest 17.6-point fastball deficit stops being remarkable once you price in the search that found it.

August 10, 2026 · 8 min read

hitting

The Park in Your Swing: Baseball's Buildings Bend the Swings Taken Inside Them. Fenway Bends Them Backwards.

Statcast's bat-tracking era makes an old broadcast claim testable: does the same hitter swing differently depending on the ballpark? Across 649 hitter-seasons and 32 physical buildings, the league-wide park pattern is real — it repeats across seasons and, for three of four swing metrics, predicted 2026 from hash-sealed 2024-25 estimates (tilt r=.73 hierarchical / .42 matched-pairs; swing length failed the sealed test). Coors' attack-angle and swing-length effects are the only named-park claims passing both independent pipelines — swings measured there run 1.46 degrees flatter. And our pre-registered Fenway prediction failed backwards: righty swings at Fenway aim AWAY from the Monster, not at it, while the lefty control hand shows nothing. The 36 hitters who changed parks for 2026 show only a drift-sized shift — adaptation transfer unproven, sealed for a 2027 re-score. Two frontier-model pipelines, three adversarial review rounds, mutual sign-off.

August 1, 2026 · 13 min read

The Long Read

The Anatomy of a Slump: What Eleven Straight Losses Actually Tell You

We backtested 491 slumps from 2021-2025: nothing about a slump — depth, luck, close losses — predicts the next 30 games beyond who the team already was. One exception: cold bats revert. Seven forecasts on the record, graded in 30 days.

The findingTeam Trends

+0.000

Out-of-sample forecasting lift from every detail of a slump beyond season record and season xwOBA differential, across 491 slumps — a null two independent frontier-model analyses tried and failed to break. The slump is the noise; the season is the signal.

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Explore the Data

Game Reports Umpire Profiles ABS Challenges Pitcher Profiles Hitter Directory Team Profiles Zone Explorer Count Calculator Challenge Optimizer Open Explore →

Should You Burn One? A Challenge Is a Wasting Asset. Teams Hoard It Anyway.

The Investigations

Where Cal Raleigh Broke — and Where He Didn't

The Book Is Good by Pitch 150. We Can't Tell You When It Was Written.

The Park in Your Swing: Baseball's Buildings Bend the Swings Taken Inside Them. Fenway Bends Them Backwards.

The Anatomy of a Slump: What Eleven Straight Losses Actually Tell You

Explore the Data

New analysis, when it's ready. No hot takes, just the receipts.