Psychometric Item Validation Using Virtual Respondents with Trait-Response Mediators
Sungjib Lim, Woojung Song, Eun-Ju Lee, Yohan Jo
TL;DR
This work tackles construct validity in psychometric item validation for large language models by introducing mediator-guided virtual respondents. It proposes a five-stage framework: select target traits from Big5/Schwartz/VIA, generate an expanded item pool, create mediators using several strategies, simulate responses with mediator-driven prompts, and rank items by convergent validity against official surveys, validated against human data. Across experiments, mediator-based item generation—especially trait-only mediator strategies—achieves top CV and high ranking performance, outperforming baselines and illustrating that LLMs can generate plausible mediators and simulate trait responses. The study provides a cost-effective benchmark, demonstrates robustness across models and scales, and highlights the importance of mediators for robust item validity, while releasing data and code to spur future work.
Abstract
As psychometric surveys are increasingly used to assess the traits of large language models (LLMs), the need for scalable survey item generation suited for LLMs has also grown. A critical challenge here is ensuring the construct validity of generated items, i.e., whether they truly measure the intended trait. Traditionally, this requires costly, large-scale human data collection. To make it efficient, we present a framework for virtual respondent simulation using LLMs. Our central idea is to account for mediators: factors through which the same trait can give rise to varying responses to a survey item. By simulating respondents with diverse mediators, we identify survey items that robustly measure intended traits. Experiments on three psychological trait theories (Big5, Schwartz, VIA) show that our mediator generation methods and simulation framework effectively identify high-validity items. LLMs demonstrate the ability to generate plausible mediators from trait definitions and to simulate respondent behavior for item validation. Our problem formulation, metrics, methodology, and dataset open a new direction for cost-effective survey development and a deeper understanding of how LLMs simulate human survey responses. We publicly release our dataset and code to support future work.
