Are Large Language Models Consistent over Value-laden Questions?
Authors: Jared Moore, Tanvi Deshpande, Diyi Yang Source: arXiv:2407.02996, July 2024
Overview
This paper investigates a critical weakness in how large language models (LLMs) are evaluated: their consistency when answering value-laden questions — questions involving ethics, politics, and other subjective or controversial topics.
Key points
- Motivation: LLM responses to value-laden questions are increasingly used to judge model alignment, bias, and safety. However, if a model's answers shift dramatically under trivial rewording, single-shot evaluations may be misleading.
- Method: The authors probe LLM responses across multiple variations of the same underlying question, including:
- Paraphrases and rephrasings of the question
- Variations in demographic framing (e.g., asking as or about different groups)
- Changes to answer-option ordering in multiple-choice formats
- Findings: Models show substantial inconsistency across these small, semantically equivalent perturbations, meaning conclusions drawn from a single query format can be unreliable or misleading.
- Implication: Evaluations of model values and trustworthiness should test robustness across multiple question formulations rather than relying on one canonical prompt (e.g., a single MMLU-style multiple-choice item).
- Original paper: Are Large Language Models Consistent over Value-laden Questions?
Takeaways
1. Single-turn, single-format evaluations overestimate the reliability of LLM behavior on subjective topics. 2. Response inconsistency is itself an important evaluation signal — a well-calibrated, trustworthy model should give stable answers to equivalent questions. 3. Practitioners assessing deployment readiness for socially sensitive applications should include consistency checks in their evaluation suites.