Retrieval or Representation? Reassessing Benchmark Gaps in Multilingual and Visually Rich RAG

Fuente: arXiv
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Main Authors: Asenov, Martin, Benkirane, Kenza, Goldwater, Dan, Ghodsi, Aneiss
Format: Preprint
Published: 2026
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author Asenov, Martin
Benkirane, Kenza
Goldwater, Dan
Ghodsi, Aneiss
author_facet Asenov, Martin
Benkirane, Kenza
Goldwater, Dan
Ghodsi, Aneiss
contents Retrieval-augmented generation (RAG) is a common way to ground language models in external documents and up-to-date information. Classical retrieval systems relied on lexical methods such as BM25, which rank documents by term overlap with corpus-level weighting. End-to-end multimodal retrievers trained on large query-document datasets claim substantial improvements over these approaches, especially for multilingual documents with complex visual layouts. We demonstrate that better document representation is the primary driver of benchmark improvements. By systematically varying transcription and preprocessing methods while holding the retrieval mechanism fixed, we demonstrate that BM25 can recover large gaps on multilingual and visual benchmarks. Our findings call for decomposed evaluation benchmarks that separately measure transcription and retrieval capabilities, enabling the field to correctly attribute progress and focus effort where it matters.
format Preprint
id arxiv_https___arxiv_org_abs_2603_04238
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Retrieval or Representation? Reassessing Benchmark Gaps in Multilingual and Visually Rich RAG
Asenov, Martin
Benkirane, Kenza
Goldwater, Dan
Ghodsi, Aneiss
Computation and Language
Retrieval-augmented generation (RAG) is a common way to ground language models in external documents and up-to-date information. Classical retrieval systems relied on lexical methods such as BM25, which rank documents by term overlap with corpus-level weighting. End-to-end multimodal retrievers trained on large query-document datasets claim substantial improvements over these approaches, especially for multilingual documents with complex visual layouts. We demonstrate that better document representation is the primary driver of benchmark improvements. By systematically varying transcription and preprocessing methods while holding the retrieval mechanism fixed, we demonstrate that BM25 can recover large gaps on multilingual and visual benchmarks. Our findings call for decomposed evaluation benchmarks that separately measure transcription and retrieval capabilities, enabling the field to correctly attribute progress and focus effort where it matters.
title Retrieval or Representation? Reassessing Benchmark Gaps in Multilingual and Visually Rich RAG
topic Computation and Language
url https://arxiv.org/abs/2603.04238