Does Item Response Theory Generalize Across Languages? Evidence from Cross-Lingual LLM Benchmarks

Ruchira Dhar, Qiwei Peng, Anders Søgaard


Abstract
The application of Item Response Theory (IRT) for data selection in benchmarks has mostly been limited to monolingual settings. In this work, we ask: how does IRT generalize when the same benchmark is translated across languages? We conduct experiments on Multilingual GSM and Global MMLU, covering over 100 language models and 11 languages. Fitting 1PL, 2PL, and 3PL IRT models per language, we assess cross-lingual consistency of parameters and whether IRT-filtered subsets preserve model rankings across languages: item *difficulty* emerges as the most stable parameter followed by *guessing* and *discrimination*. A differential item analysis also shows that lack of stability can be tracked to specific items shifting under translation across languages. Our findings suggest IRT-based selection in multilingual settings must be both parameter-aware and item-aware, validating model choice and screening individual items before assuming cross-lingual generalization.
Anthology ID:
2026.findings-emnlp.1889
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:
40260–40281
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1889/
DOI:
10.18653/2026.findings-emnlp.1889
Bibkey:
Cite (ACL):
Ruchira Dhar, Qiwei Peng, and Anders Søgaard. 2026. Does Item Response Theory Generalize Across Languages? Evidence from Cross-Lingual LLM Benchmarks. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 40260–40281, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Does Item Response Theory Generalize Across Languages? Evidence from Cross-Lingual LLM Benchmarks (Dhar et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1889.pdf