Diagnosing Translated Benchmarks: An Automated Quality Assurance Study of the EU20 Benchmark Suite

Klaudia Thellmann, Bernhard Stadler, Michael Färber


Abstract
Machine-translated benchmark datasets reduce costs and offer scale, but noise, loss of structure, and uneven quality weaken confidence. What matters is not merely whether we can translate, but also whether we can measure and verify translation reliability at scale. We study translation quality in the EU20 benchmark suite, which comprises five established benchmarks translated into 20 languages, via a three-step automated quality assurance approach: (i) a structural corpus audit with targeted fixes; (ii) quality profiling using a neural metric (COMET, reference-free and reference-based) with translation service comparisons (DeepL / ChatGPT / Google); and (iii) an LLM-based span-level translation error landscape. Trends are consistent: datasets with lower COMET scores exhibit a higher share of accuracy/mistranslation errors at span level (notably HellaSwag; ARC is comparatively clean). Reference-based COMET on MMLU against human-edited samples points in the same direction. We release cleaned/corrected versions of the EU20 datasets, and code for reproducibility. In sum, automated quality assurance offers practical, scalable indicators that help prioritize review – complementing, not replacing, human gold standards.
Anthology ID:
2026.lrec-main.710
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
9030–9043
Language:
URL:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.710/
DOI:
Bibkey:
Cite (ACL):
Klaudia Thellmann, Bernhard Stadler, and Michael Färber. 2026. Diagnosing Translated Benchmarks: An Automated Quality Assurance Study of the EU20 Benchmark Suite. International Conference on Language Resources and Evaluation, main:9030–9043.
Cite (Informal):
Diagnosing Translated Benchmarks: An Automated Quality Assurance Study of the EU20 Benchmark Suite (Thellmann et al., LREC 2026)
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PDF:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.710.pdf