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Main Authors: Zhang, Zichen, Zhang, Kunlong, Ruan, Hongwei, Luo, Yiming
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.21845
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author Zhang, Zichen
Zhang, Kunlong
Ruan, Hongwei
Luo, Yiming
author_facet Zhang, Zichen
Zhang, Kunlong
Ruan, Hongwei
Luo, Yiming
contents Transformer-based models have advanced the field of question answering, but multi-hop reasoning, where answers require combining evidence across multiple passages, remains difficult. This paper presents a comprehensive evaluation of retrieval strategies for multi-hop question answering within a retrieval-augmented generation framework. We compare cosine similarity, maximal marginal relevance, and a hybrid method that integrates dense embeddings with lexical overlap and re-ranking. To further improve retrieval, we adapt the EfficientRAG pipeline for query optimization, introducing token labeling and iterative refinement while maintaining efficiency. Experiments on the HotpotQA dataset show that the hybrid approach substantially outperforms baseline methods, achieving a relative improvement of 50 percent in exact match and 47 percent in F1 score compared to cosine similarity. Error analysis reveals that hybrid retrieval improves entity recall and evidence complementarity, while remaining limited in handling distractors and temporal reasoning. Overall, the results suggest that hybrid retrieval-augmented generation provides a practical zero-shot solution for multi-hop question answering, balancing accuracy, efficiency, and interpretability.
format Preprint
id arxiv_https___arxiv_org_abs_2509_21845
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Comprehensive Evaluation of Transformer-Based Question Answering Models and RAG-Enhanced Design
Zhang, Zichen
Zhang, Kunlong
Ruan, Hongwei
Luo, Yiming
Computer Vision and Pattern Recognition
Transformer-based models have advanced the field of question answering, but multi-hop reasoning, where answers require combining evidence across multiple passages, remains difficult. This paper presents a comprehensive evaluation of retrieval strategies for multi-hop question answering within a retrieval-augmented generation framework. We compare cosine similarity, maximal marginal relevance, and a hybrid method that integrates dense embeddings with lexical overlap and re-ranking. To further improve retrieval, we adapt the EfficientRAG pipeline for query optimization, introducing token labeling and iterative refinement while maintaining efficiency. Experiments on the HotpotQA dataset show that the hybrid approach substantially outperforms baseline methods, achieving a relative improvement of 50 percent in exact match and 47 percent in F1 score compared to cosine similarity. Error analysis reveals that hybrid retrieval improves entity recall and evidence complementarity, while remaining limited in handling distractors and temporal reasoning. Overall, the results suggest that hybrid retrieval-augmented generation provides a practical zero-shot solution for multi-hop question answering, balancing accuracy, efficiency, and interpretability.
title A Comprehensive Evaluation of Transformer-Based Question Answering Models and RAG-Enhanced Design
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2509.21845