These diverse approaches showcase innovative strategies in
RAG retrieval enhancement, aiming to elevate model perfor-
mance and effectiveness.
6.3 Augmentation Process
Most RAG research typically only performs a single retrieval
and generation process. However, single retrievals may con-
tain redundant information, leading to a ”lost in the mid-
dle” phenomenon[Liu et al., 2023]. This redundant informa-
tion can obscure key information or contain information con-
trary to the real answer, negatively impacting the generation
effect[Yoran et al., 2023]. Additionally, the information ob-
tained from a single retrieval is limited in problems requiring
multi-step reasoning.
Retrieval-AugmentedGenerationforLargeLanguageModels-ASurvey