The Benchmark Is Not the Construct: Toward Distribution-Based Evaluation in NLP

Haithem Afli, Manuel Frank


Abstract
Current NLP evaluation often treats a scalar score on a fixed benchmark dataset as if it directly measured the construct the benchmark is intended to represent. This Measurement-as-Instance paradigm is appropriate for a fixed evaluation configuration, but can suppress uncertainty, variance, and robustness when a single result is used to support broader capability or generalisation claims. In this position paper, we argue for extending static evaluation with Measurement-as-Distribution: a structured evaluation procedure involving principled data generation, validated perturbations, repeated evaluation, and distributional reporting. The framework is configurable: the amount of distributional evidence required should scale with the strength and breadth of the claims being made. We synthesise existing robustness, dynamic-evaluation, prompt-sensitivity, and uncertainty-reporting practices into a general measurement-theoretic framework for distribution-based NLP evaluation and provide a call to action for more rigorous reporting. Using the protocol 𝒫 = (𝒞, G, 𝛷, E, R), we identify three risks of relying exclusively on fixed scalar evaluation and derive implications for peer review, benchmark publication, leaderboard reporting, and computational cost. Two case studies demonstrate feasibility: a SQuAD evaluation of 14 models reveals modest but axis-specific performance changes and stable overall rankings with uncertainty-aware comparisons, while a verifier-backed Knights-and-Knaves study illustrates how perturbations of rigid logical tasks can be generated and validated formally.
Anthology ID:
2026.findings-emnlp.1992
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
42441–42465
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1992/
DOI:
Bibkey:
Cite (ACL):
Haithem Afli and Manuel Frank. 2026. The Benchmark Is Not the Construct: Toward Distribution-Based Evaluation in NLP. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 42441–42465, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
The Benchmark Is Not the Construct: Toward Distribution-Based Evaluation in NLP (Afli & Frank, Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1992.pdf