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arxiv: 2605.16237 · v2 · pith:GOIG6ITKnew · submitted 2026-05-15 · 💻 cs.CY · cs.HC

Inside Baseball: The Automated Ball-Strike System as an Object Lesson in Technological Rule Enforcement

Andrea Wen-Yi Wang , Waki Kamino , David Mimno , Karen Levy , Malte F. Jung This is my paper

Pith reviewed 2026-05-19 21:40 UTC · model grok-4.3

classification 💻 cs.CY cs.HC
keywords rule automationtechnological enforcementstrike zoneAutomated Ball-Strike Systemsociotechnical systemsground truthMLBstakeholder values
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The pith

Even a clearly defined rule like the baseball strike zone demands a complex translation process before it can be automated by technology.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper uses the case of Major League Baseball's Automated Ball-Strike System to show that clear rules are not straightforward to implement with technology. The strike zone, despite its precise rulebook definition, required seven years of experimentation because its practical application has always combined the official definition with umpires' judgments. Any technological system must also navigate an established network of interests among players, coaches, fans, and officials. These factors create a gap between the written rule and workable automation that goes beyond simple measurement accuracy. The authors argue that evaluation should focus on how the system functions in everyday use rather than its fidelity to the original rule text.

Core claim

The paper's core claim is that distance exists between a clear rule and its technological implementation because the ground truth of the strike zone has historically been contested as a hybrid of rule and practice, and because ABS must be embedded in an ecosystem that balances multiple stakeholder values. This challenges evaluation approaches that only measure deviation from the formalized rule.

What carries the argument

The complex translation process required to operationalize a rule through technology, which reconciles historical enforcement practices with current stakeholder priorities.

Load-bearing premise

Implementation difficulties arise primarily from the contested historical ground truth of the rule and the requirement to balance stakeholder values in the ecosystem, as opposed to purely technical challenges in measurement.

What would settle it

If researchers could deploy an automated ball-strike system that matches the rulebook definition perfectly on first use without any historical adjustments or stakeholder consultations, that would indicate the claim is incorrect.

Figures

Figures reproduced from arXiv: 2605.16237 by Andrea Wen-Yi Wang, David Mimno, Karen Levy, Malte F. Jung, Waki Kamino.

Figure 1
Figure 1. Figure 1: The official strike zone per the MLB rulebook, a three [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Making the strike zone visible. (a) The Brooklyn Dodgers experimented with electronic strike zones in the 1950s. Sports Studio Photos/Getty Images Sport via Getty Images [62]. (b) ESPN began to overlay a computer graphic called the ‘K-Zone’ since 2001 in their televised broadcast. YouTube video, posted by Detlef, 0:59 [26]. Despite the rules designating um￾pires as the final arbiters of strike zones, there… view at source ↗
Figure 3
Figure 3. Figure 3: Moving the ABS strike zone from the front of home plate (red) to [PITH_FULL_IMAGE:figures/full_fig_p011_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: MLB designed a roughly 10-second video to play when players invoke ABS to challenge an umpire’s call. This video [PITH_FULL_IMAGE:figures/full_fig_p013_4.png] view at source ↗
read the original abstract

Clearly-defined rules are often assumed to be straightforward to automate and evaluate. We challenge this assumption through an in-depth study of Major League Baseball's (MLB) seven-year experimentation with the Automated Ball-Strike System (ABS). ABS is envisioned to call balls and strikes accurately: a seemingly straightforward use of technology to objectively determine the distance between a pitch and the strike zone. Although the strike zone is an area clearly defined in the rulebook, it took MLB seven years to figure out how to automate calling balls and strikes with ABS, showing how even seemingly straightforward rules require a complex translation process to operationalize via technological systems. In this paper, we trace the design decisions that led to the current implementation of ABS. Our case study reveals that "distance" exists even between a clear rule and its technological implementation. Using analytic frameworks from Science and Technology Studies (STS), we show that such distance exists because (1) historically, the "ground truth" of the strike zone is contested: the rule in practice has always reflected a hybrid between the rulebook definition and umpires' enforcement decisions; and (2) the use of ABS is embedded in an existing eco-system, where the implementation of a technological enforcement system needs to balance multiple stakeholder values. This perspective challenges conventional evaluation paradigms that center on the distance between a formalized rule and its technological implementation, and instead calls for evaluating how such systems are experienced in practice. Addressing this question requires in-depth social science approaches, contributing to ongoing conversations in FAccT about the implementation and evaluation of sociotechnical systems.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript presents an in-depth case study of Major League Baseball's seven-year development of the Automated Ball-Strike System (ABS). It argues that, despite the strike zone being clearly defined in the rulebook, automation required complex sociotechnical translation due to (1) historical contestation of the strike zone's 'ground truth' as a hybrid of rulebook definition and umpire enforcement practice, and (2) the need to balance multiple stakeholder values within the existing baseball ecosystem. Drawing on Science and Technology Studies (STS) frameworks, the paper challenges conventional evaluation paradigms that focus on the distance between a formalized rule and its technological implementation, instead advocating for assessing how such systems are experienced in practice via social science methods. This contributes to FAccT conversations on sociotechnical system implementation and evaluation.

Significance. If the interpretive claims hold, the work provides a concrete, historically grounded example that advances FAccT scholarship by demonstrating why even apparently objective, rulebook-defined tasks resist straightforward automation. The in-depth tracing of design decisions and use of STS analytic frameworks are strengths that can inform broader discussions of fairness, accountability, and transparency in automated enforcement systems outside sports. The paper explicitly positions its contribution as calling for interdisciplinary social science approaches rather than purely technical metrics.

major comments (2)
  1. [Design decisions tracing (around the seven-year experimentation narrative)] The central claim that non-technical factors (contested ground truth and stakeholder balancing) primarily drove the seven-year timeline rests on the tracing of design decisions. However, the manuscript does not provide a chronological breakdown or evidence separating periods spent on technical measurement challenges (sensor calibration, 3D zone computation, real-time tracking accuracy) from sociotechnical negotiations. Without this separation, it is difficult to substantiate that technical hurdles were secondary or resolved early, weakening the challenge to conventional evaluation paradigms.
  2. [Historical analysis of umpiring practice] The abstract and case study assert that the strike zone rule in practice has always reflected a hybrid between rulebook and umpires' decisions, but the evidence for this historical contestation is presented at a high level. A more detailed account of specific historical sources or changes in enforcement practice over time would strengthen the load-bearing claim that ground truth was contested prior to ABS.
minor comments (2)
  1. [Overall structure] The manuscript would benefit from a dedicated methods subsection explicitly listing the primary sources (documents, interviews, or observations) used to trace design decisions, to allow readers to assess the robustness of the STS interpretation.
  2. [Introduction and framing] Some STS terminology (e.g., 'ecosystem,' 'translation process') is introduced without a brief definition or reference on first use, which may reduce accessibility for readers outside the STS subfield.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive and detailed comments, which identify opportunities to clarify the manuscript's core arguments. We address each major comment below and commit to revisions that strengthen the presentation of evidence without altering the underlying analysis.

read point-by-point responses

  1. Referee: The central claim that non-technical factors (contested ground truth and stakeholder balancing) primarily drove the seven-year timeline rests on the tracing of design decisions. However, the manuscript does not provide a chronological breakdown or evidence separating periods spent on technical measurement challenges (sensor calibration, 3D zone computation, real-time tracking accuracy) from sociotechnical negotiations. Without this separation, it is difficult to substantiate that technical hurdles were secondary or resolved early, weakening the challenge to conventional evaluation paradigms.

    Authors: We appreciate this observation on the need for clearer separation in the timeline. The current narrative in Sections 4 and 5 traces key design decisions in sequence and draws on interview data indicating that core sensor and tracking accuracy thresholds were achieved relatively early, with later delays tied to stakeholder consultations. To make this distinction more explicit and directly address the referee's concern, we will add a new table in the revised manuscript that maps the seven-year period into phases, annotating technical milestones versus sociotechnical negotiations based on the available documentation and interviews. This addition will better substantiate the claim that non-technical factors extended the timeline. revision: yes

  2. Referee: The abstract and case study assert that the strike zone rule in practice has always reflected a hybrid between rulebook and umpires' decisions, but the evidence for this historical contestation is presented at a high level. A more detailed account of specific historical sources or changes in enforcement practice over time would strengthen the load-bearing claim that ground truth was contested prior to ABS.

    Authors: We agree that expanding the historical evidence would reinforce this foundational claim. The manuscript currently references the hybrid character of the strike zone through secondary sources on umpiring practice, but we will revise the relevant subsection to include more granular examples, such as documented shifts in enforcement following rule clarifications in the mid-20th century and empirical studies of umpire bias from the 1990s onward. These additions will draw on publicly available historical records and prior research to provide concrete illustrations of contestation before ABS development. revision: yes

Circularity Check

0 steps flagged

No circularity: argument rests on external historical facts and STS frameworks

full rationale

The paper presents a qualitative case study tracing MLB's seven-year ABS design process. Its core claim—that even a rulebook-clear strike zone requires sociotechnical translation due to historically contested ground truth and stakeholder value balancing—is supported by cited historical umpiring practices and external STS literature rather than any self-referential definitions, fitted parameters renamed as predictions, or load-bearing self-citations. No equations, quantitative fits, or uniqueness theorems appear; the derivation does not reduce to its inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The paper relies on standard STS assumptions about the social construction of technical systems and the hybrid nature of rule enforcement; no free parameters or invented entities are introduced as the work is interpretive rather than formal or quantitative.

axioms (1)
  • domain assumption STS frameworks are appropriate for analyzing the operationalization of rules in technological systems
    Invoked throughout the abstract to frame the distance between rule and implementation

pith-pipeline@v0.9.0 · 5830 in / 1289 out tokens · 50337 ms · 2026-05-19T21:40:02.630893+00:00 · methodology

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