Retrieval signals do not improve adaptive routing over query alone
Beyond the Query: Do Retrieval Signals Improve Adaptive Multimodal RAG Routing?
Machine LearningArtificial Intelligence
Summary
When deciding which search or analysis steps to take on documents, audio, or video, it might help to use clues from the search results themselves. The authors tested if these extra clues improve decisions compared to just using the original question. They found that adding these retrieval clues did not consistently lead to better choices. So, you shouldn’t assume these clues help unless you check carefully by comparing to using only the original question.
What this means in practice
- •For information retrieval engineers: Design query routing systems that rely primarily on the query content rather than retrieval stage signals for document, audio, and video search.
- •For multimodal system developers: Simplify adaptive step decisions in multimodal retrieval by focusing on query features instead of retrieval step metrics to decide routing actions.
Authors
Qiaomu Li, Qiuyuan Zhang, Nong Ming
Abstract
Adaptive RAG often uses retrieval-time signals to decide whether another retrieval, reranking, or multimodal step should run. We ask whether these signals add routing value once the query itself is already known. Across document, audio, and video RAG, we compare matched query-only and query+retrieval routers while holding the optional actions, router family, training procedure, and evaluation fixed. On the held-out final evaluation, adding the tested retrieval signals does not produce a reliable routing improvement over the query-only baseline. Some retrieval signals are associated with whether a later step will help, but that predictability does not consistently lead to bet- ter RUN/SKIP decisions. The main lesson is therefore methodological: retrieval-state features should not be credited with routing value unless they improve over a matched query-only control. Our results do not show that routing or retrieval state is generally useless; they show that the incremental value of retrieval signals must be demonstrated rather than assumed.