CLARINET: Augmenting Language Models to Ask Clarification Questions for Retrieval
Yizhou Chi, Jessy Lin, Kevin Lin, Dan Klein
TL;DR
CLARINET addresses ambiguity in retrieval by training an LLM to generate clarification questions conditioned on the retriever distribution, producing a language posterior to re-rank candidates. It distills explicit question-search exploration into end-to-end learning via FiD, enabling cheaper inference while outperforming information-theoretic baselines (EIG, KL) and vanilla prompting by substantial margins. On a real TOT book dataset, CLARINET achieves a top-1 retrieval and MRR improvement, with delta-training yielding the strongest gains (MRR ≈ 0.659; cumulative retrieval ≈ 0.764). The approach highlights the value of summarizing dialogue into a language posterior and using a fusion-based encoder-decoder to condition question generation on per-candidate context.
Abstract
Users often make ambiguous requests that require clarification. We study the problem of asking clarification questions in an information retrieval setting, where systems often face ambiguous search queries and it is challenging to turn the uncertainty in the retrieval model into a natural language question. We present CLARINET, a system that asks informative clarification questions by choosing questions whose answers would maximize certainty in the correct candidate. Our approach works by augmenting a large language model (LLM) to condition on a retrieval distribution, finetuning end-to-end to generate the question that would have maximized the rank of the true candidate at each turn. When evaluated on a real-world retrieval dataset of users searching for books, our system outperforms traditional heuristics such as information gain on retrieval success by 17% and vanilla-prompted LLMs by 39% relative.
