Conversational question answering increasingly relies on retrieval-augmented generation (RAG) to ground large language models (LLMs) in external knowledge. Yet, most existing studies evaluate RAG methods in isolation and primarily focus on single-turn settings. This paper addresses the lack of a systematic comparison of RAG methods for multi-turn conversational QA, where dialogue history, coreference, and shifting user intent substantially complicate retrieval. We present a comprehensive empirical study of vanilla and advanced RAG methods across eight diverse conversational QA datasets spanning multiple domains. Using a unified experimental setup, we evaluate retrieval quality and answer generation using generator and retrieval metrics, and analyze how performance evolves across conversation turns. Our results show that robust yet straightforward methods, such as reranking, hybrid BM25, and HyDE, consistently outperform vanilla RAG. In contrast, several advanced techniques fail to yield gains and can even degrade performance below the No-RAG baseline. We further demonstrate that dataset characteristics and dialogue length strongly influence retrieval effectiveness, explaining why no single RAG strategy dominates across settings. Overall, our findings indicate that effective conversational RAG depends less on method complexity than on alignment between the retrieval strategy and the dataset structure. We publish the code used.\footnote{\href{https://github.com/Klejda-A/exp-rag.git}{GitHub Repository}}
Gaoling School of Artificial Intelligence, Renmin University of China(中国人民大学高瓴人工智能学院);Beijing Academy of Artificial Intelligence(北京人工智能研究院);Huawei Poisson Lab(华为泊松实验室);Waseda University(早稻田大学)
A Comparison of Conversational Models and Humans in Answering Technical Questions: the Firefox Case
Pontifical Catholic University(天主教大学);Mozilla Corporation(Mozilla公司);Federal University of Rio de Janeiro(里约热内卢联邦大学);Oregon State University(俄勒冈州立大学);Northern Arizona University(北亚利桑那大学)
Ask in Any Modality: A Comprehensive Survey on Multimodal Retrieval-Augmented Generation
Computer Engineering Department, Sharif University of Technology(沙斐大学计算机工程系);College of Interdisciplinary Science and Technology, University of Tehran(德黑兰大学跨学科科学与技术学院);Computer Engineering Department, K.N. Toosi University of Technology(技术学院计算机工程系);Qatar Computing Research Institute(卡塔尔计算研究院)
Modular RAG: Transforming RAG Systems into LEGO-like Reconfigurable Frameworks
Shanghai Research Institute for Intelligent Autonomous Systems, Tongji University(同济大学上海智能自主系统研究院);College of Design and Innovation, Tongji University(同济大学设计创意学院)
RAG4ITOps: A Supervised Fine-Tunable and Comprehensive RAG Framework for IT Operations and Maintenance
Shanghai Business School(上海商学院);University of North Carolina Greensboro(北卡罗来纳州格林斯堡大学);Skema Business School(Skema商学院);North Carolina Central University(北卡罗来纳州立大学)
CRUD-RAG: A Comprehensive Chinese Benchmark for Retrieval-Augmented Generation of Large Language Models
University of Science and Technology of China(中国科学技术大学);Institute for Advanced Algorithms Research (Shanghai)((上海)高级算法研究院);Renmin University of China(中国人民大学);AI Research Institute(360人工智能研究院)
Retrieval Augmented Generation Evaluation in the Era of Large Language Models: A Comprehensive Survey
State Key Laboratory of Cognitive Intelligence, University of Science and Technology of China(认知智能国家重点实验室,中国科学技术大学);McGill University(麦吉尔大学);Tencent Company(腾讯公司);Artificial Intelligence Research Institute, iFLYTEK Co., Ltd(人工智能研究院,iFLYTEK公司)
DH-RAG: A Dynamic Historical Context-Powered Retrieval-Augmented Generation Method for Multi-Turn Dialogue
Hong Kong University of Science and Technology(香港科技大学);Huazhong University of Science and Technology(华中科技大学);University of California San Diego(加州大学圣地亚哥分校);University of Science and Technology of China(中国科学技术大学);Beihang University(北京航空航天大学)
FlexRAG: A Flexible and Comprehensive Framework for Retrieval-Augmented Generation
Key Laboratory of Intelligent Information Processing, Institute of Computing Technology, Chinese Academy of Sciences (ICT/CAS)(中国科学院智能信息处理重点实验室);University of Chinese Academy of Sciences, China(中国科学院大学);Key Laboratory of AI Safety, Chinese Academy of Sciences(中国科学院人工智能安全重点实验室);Institute of Computing and Intelligence, Harbin Institute of Technology (Shenzhen), China(哈尔滨工业大学(深圳)计算机与智能信息研究院)