[2603.08819] Beyond Relevance: On the Relationship Between Retrieval and RAG Information Coverage

Computer Science > Information Retrieval arXiv:2603.08819 (cs) [Submitted on 9 Mar 2026 (v1), last revised 14 Apr 2026 (this version, v3)] Title:Beyond Relevance: On the Relationship Between Retrieval and RAG Information Coverage Authors:Saron Samuel, Alexander Martin, Eugene Yang, Andrew Yates, Dawn Lawrie, Laura Dietz, Benjamin Van Durme View a PDF of the paper titled Beyond Relevance: On the Relationship Between Retrieval and RAG Information Coverage, by Saron Samuel and 6 other authors View PDF Abstract:Retrieval-augmented generation (RAG) systems combine document retrieval with a generative model to address complex information seeking tasks like report generation. While the relationship between retrieval quality and generation effectiveness seems intuitive, it has not been systematically studied. We investigate whether upstream retrieval metrics can serve as reliable early indicators of the final generated response's information coverage. Through experiments across two text RAG benchmarks (TREC NeuCLIR 2024 and TREC RAG 2024) and one multimodal benchmark (WikiVideo), we analyze 15 text retrieval stacks and 10 multimodal retrieval stacks across four RAG pipelines and multiple evaluation frameworks (Auto-ARGUE and MiRAGE). Our findings demonstrate strong correlations between coverage-based retrieval metrics and nugget coverage in generated responses at both topic and system levels. This relationship holds most strongly when retrieval objectives align with generation goa...