@inproceedings{zhao-etal-2026-validity,
title = "Validity-Aware Assessment of {LLM} Value Orientation via Subset Item Response Theory",
author = "Zhao, Qinlin and
Yi, Xiaoyuan and
Yao, Jing and
Huang, Muhua and
Lian, Defu and
Xie, Xing",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.emnlp-main.2578/",
pages = "58592--58615",
ISBN = "979-8-89176-459-0",
abstract = "Measuring the value orientations of LLMs is helpful for diagnosing model risk and understanding their misalignment behavior. However, existing value benchmarks are often AI-generated and lack validity verification, leading to noisy and unreliable results. Inspired by Psychometrics, we propose a novel Subset Item Response Theory (S-IRT) model for assessing LLMs' values under any value theories. S-IRT directly models the subset of values jointly expressed in each LLM response, rather than reducing responses to binary outcomes as in traditional IRT-based ability assessment. Meanwhile, it jointly estimates the LLM{'}s latent values and captures the relative priorities among them. Based on it, we further design a tailored information reward that estimates the information gain of each item in reducing uncertainty about the evaluated model{'}s value, and thus helps select a small set of high-quality items from existing benchmarks. Extensive experiments on 23 popular LLMs and three value systems (21 value dimensions) demonstrate S-IRT can be applied to multiple value systems simultaneously and improve evaluation reliability and validity. The information reward also helps reduce the number of questions to as few as 200 while preserving comparable evaluation effectiveness."
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%0 Conference Proceedings
%T Validity-Aware Assessment of LLM Value Orientation via Subset Item Response Theory
%A Zhao, Qinlin
%A Yi, Xiaoyuan
%A Yao, Jing
%A Huang, Muhua
%A Lian, Defu
%A Xie, Xing
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-459-0
%F zhao-etal-2026-validity
%X Measuring the value orientations of LLMs is helpful for diagnosing model risk and understanding their misalignment behavior. However, existing value benchmarks are often AI-generated and lack validity verification, leading to noisy and unreliable results. Inspired by Psychometrics, we propose a novel Subset Item Response Theory (S-IRT) model for assessing LLMs’ values under any value theories. S-IRT directly models the subset of values jointly expressed in each LLM response, rather than reducing responses to binary outcomes as in traditional IRT-based ability assessment. Meanwhile, it jointly estimates the LLM’s latent values and captures the relative priorities among them. Based on it, we further design a tailored information reward that estimates the information gain of each item in reducing uncertainty about the evaluated model’s value, and thus helps select a small set of high-quality items from existing benchmarks. Extensive experiments on 23 popular LLMs and three value systems (21 value dimensions) demonstrate S-IRT can be applied to multiple value systems simultaneously and improve evaluation reliability and validity. The information reward also helps reduce the number of questions to as few as 200 while preserving comparable evaluation effectiveness.
%U https://aclanthology.org/2026.emnlp-main.2578/
%P 58592-58615
Markdown (Informal)
[Validity-Aware Assessment of LLM Value Orientation via Subset Item Response Theory](https://aclanthology.org/2026.emnlp-main.2578/) (Zhao et al., EMNLP 2026)
ACL