Aligning Language Models to Explicitly Handle Ambiguity
Hyuhng Joon KimYouna KimCheonbok ParkJunyeob KimChoonghyun ParkKang Min YooSang-goo LeeTaeuk Kim
Proposes an alignment framework that enables language models to detect query ambiguity based on their own internal knowledge and proactively ask clarifying questions without degrading performance on unambiguous inputs.
When users interact with large language models, their queries frequently lack precision or omit key details. While a human might ask for clarification, current artificial intelligence models typically select an arbitrary interpretation and provide a single answer. In high-stakes fields such as healthcare and law, misinterpreting an ambiguous query introduces severe operational, safety, and compliance risks. Standard language models fail to address this issue because they are not explicitly trained to ask for clarification, and their recognition of ambiguity depends entirely on their internal knowledge scope.
The article introduces and evaluates a four-stage training framework called Alignment with Perceived Ambiguity (APA). This approach teaches models to explicitly identify ambiguous inputs and request clarification by evaluating ambiguity from the model's own perspective, rather than relying strictly on pre-defined human labels.
The authors evaluated their approach using open-source models (LLaMA-2 and Mistral) across five question-answering datasets, including AmbigQA, SituatedQA, and three newly introduced benchmarks (AmbigTriviaQA, AmbigWebQuestions, and AmbigFreebaseQA). The framework operates by first identifying queries that a model fails to answer correctly, prompting the model to add clarifying details, and measuring the resulting drop in model uncertainty (information gain). Queries with high information gain are classified as ambiguous from the model's perspective. The model is then fine-tuned to answer clear questions directly while generating explicit clarification requests for queries it perceives as ambiguous.
Across all test benchmarks, APA consistently outperformed standard prompting methods, uncertainty sampling techniques, and models fine-tuned on full human-annotated datasets. Prompting alone proved ineffective, either failing to catch ambiguous queries entirely or excessively triggering clarification requests for clear questions. Models trained with APA achieved up to a 6-point improvement in ambiguity detection accuracy while maintaining high accuracy on clear queries. Furthermore, APA required only 13% to 32% of the training data used by full-dataset fine-tuning, demonstrating that training on model-perceived ambiguity is more effective than training on much larger volumes of static, human-labeled data.
These findings indicate that aligning models to their own internal knowledge boundaries substantially improves reliability and safety. By requesting clarification only when necessary, models reduce the risk of confident but incorrect assumptions without degrading everyday performance. The efficiency of the data selection process also highlights that high-quality, model-tailored data curation can reduce training compute costs and time compared to traditional large-scale fine-tuning.
Organizations deploying conversational systems should transition away from simple ambiguity-prompting strategies and adopt training pipelines that leverage model uncertainty and perceived ambiguity. System designers should evaluate whether to use fixed clarification templates, which offer slightly higher detection stability, or generated clarifications, which provide a more tailored user experience. Because the study focused on single-turn, short-form questions using small-to-medium open-source models, further validation is recommended. Organizations should conduct pilot tests before applying this framework to multi-turn conversational agents, long-form reasoning tasks, and proprietary commercial models.
- Paper: Selectively Answering Ambiguous Questions, Jeremy R. Cole et al. (2023). Read this earlier study of selectively answering ambiguous questions to understand the ambiguity-aware abstention problem that APA turns into an explicit clarification-training framework.
- Paper: Tree of Clarifications: Answering Ambiguous Questions with Retrieval-Augmented Large Language Models, Gangwoo Kim et al. (2023). Its retrieval-based method for branching ambiguous queries into distinct interpretations provides useful prior context for APA’s choice to identify ambiguity and seek clarification.
- Paper: RefusalBench: Generative Evaluation of Selective Refusal in Grounded Language Models, Aashiq Muhamed et al. (2025). This later benchmark extends ambiguity-aware handling into grounded systems, testing whether models can distinguish ambiguity from other information failures and refuse for the right reason.
