A Tale of Trust and Accuracy: Base vs. Instruct LLMs in RAG Systems
On the map: Retrieval-augmented generation → RAG pipeline design and evaluation
Abstract (arXiv)
Retrieval Augmented Generation (RAG) represents a significant advancement in artificial intelligence combining a retrieval phase with a generative phase, with the latter typically being powered by large language models (LLMs). The current common practices in RAG involve using "instructed" LLMs, which are fine-tuned with supervised training to enhance their ability to follow instructions and are aligned with human preferences using state-of-the-art techniques. Contrary to popular belief, our study demonstrates that base models outperform their instructed counterparts in RAG tasks by 20% on average under our experimental settings. This finding challenges the prevailing assumptions about the superiority of instructed LLMs in RAG applications. Further investigations reveal a more nuanced situation, questioning fundamental aspects of RAG and suggesting the need for broader discussions on the topic; or, as Fromm would have it, "Seldom is a glance at the statistics enough to understand the meaning of the figures".
Key facts. Cited by 3 papers in the map (data through 13 Oct 2026). Placed in RAG pipeline design and evaluation, one of 15 directions in Retrieval-augmented generation. Builds on 35 of its 46 references that are in the map. First posted on arXiv 21 Jun 2024.
Builds on
35 of 46 references.
Closest ancestors · 2
Same direction, newest first
- 2024Evaluation of Retrieval-Augmented Generation: A Survey13 May
- 2024The Power of Noise: Redefining Retrieval for RAG Systems26 Jan
Other references · 33
- 2022Training language models to follow instructions with human feedbackcited by 15,856
- 2023Llama 2: Open Foundation and Fine-Tuned Chat Modelscited by 12,979
- 2020Retrieval-Augmented Generation for Knowledge-Intensive NLP Taskscited by 9,221
- 2023Direct Preference Optimization: Your Language Model is Secretly a Reward Modelcited by 7,986
- 2020Dense Passage Retrieval for Open-Domain Question Answeringcited by 3,797
- 2018HotpotQA: A Dataset for Diverse, Explainable Multi-hop Question Answeringcited by 3,716
- 2023Lost in the Middle: How Language Models Use Long Contextscited by 3,412
- 2017TriviaQA: A Large Scale Distantly Supervised Challenge Dataset for Reading Comprehensioncited by 2,925
- 2017Billion-scale similarity search with GPUscited by 2,490
- 2023Self-RAG: Learning to Retrieve, Generate, and Critique through Self-Reflectioncited by 1,815
- 2023GQA: Training Generalized Multi-Query Transformer Models from Multi-Head Checkpointscited by 1,323
- 2021Unsupervised Dense Information Retrieval with Contrastive Learningcited by 1,205
21 more
- 2022When Not to Trust Language Models: Investigating Effectiveness of Parametric and Non-Parametric Memoriescited by 1,111
- 2018The Secret Sharer: Evaluating and Testing Unintended Memorization in Neural Networkscited by 864
- 2023Large Language Models Can Be Easily Distracted by Irrelevant Contextcited by 829
- 2019Fast Transformer Decoding: One Write-Head is All You Needcited by 705
- 2019Latent Retrieval for Weakly Supervised Open Domain Question Answeringcited by 693
- 2021Retrieval Augmentation Reduces Hallucination in Conversationcited by 692
- 2023Enabling Large Language Models to Generate Text with Citationscited by 588
- 2020KILT: a Benchmark for Knowledge Intensive Language Taskscited by 571
- 2024ORPO: Monolithic Preference Optimization without Reference Modelcited by 558
- 2023The Falcon Series of Open Language Modelscited by 533
- 2022Large Language Models Struggle to Learn Long-Tail Knowledgecited by 455
- 2021Entity-Based Knowledge Conflicts in Question Answeringcited by 352
- 2023Adaptive Chameleon or Stubborn Sloth: Revealing the Behavior of Large Language Models in Knowledge Conflictscited by 337
- 2024Is DPO Superior to PPO for LLM Alignment? A Comprehensive Studycited by 262
- 2024RAFT: Adapting Language Model to Domain Specific RAGcited by 261
- 2021Hurdles to Progress in Long-form Question Answeringcited by 166
- 2024ClashEval: Quantifying the tug-of-war between an LLM's internal prior and external evidencecited by 112
- 2021Measure and Improve Robustness in NLP Models: A Surveycited by 107
- 2019A Discrete Hard EM Approach for Weakly Supervised Question Answeringcited by 78
- 2024UniMS-RAG: A Unified Multi-source Retrieval-Augmented Generation for Personalized Dialogue Systemscited by 38
- 2024FaaF: Facts as a Function for the evaluation of generated textcited by 5
Built on by
Citing papers per year: 2024: 1; 2025: 1; 2026: 1.
3 papers.
- 2024Understanding the Fundamental Design Decisions of Retrieval-Augmented Generation Systemscited by 7
- 2025Improving Instruct Models for Free: A Study on Partial Adaptationcited by 2
- 2026Automatic or Controlled? Repetition Priming Reveals Divergent Processing in Base LLMs, Instruct LLMs, and Humanscited by 0
- 2026Automatic or Controlled? Repetition Priming Reveals Divergent Processing in Base LLMs, Instruct LLMs, and Humans5 Aug 2026
- 2025Improving Instruct Models for Free: A Study on Partial Adaptation15 Apr 2025
- 2024Understanding the Fundamental Design Decisions of Retrieval-Augmented Generation Systems29 Nov 2024
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- 2026Is Agentic RAG worth it? An experimental comparison of RAG approaches
- 2024Towards Understanding Systems Trade-offs in Retrieval-Augmented Generation Model Inference
- 2025Post-training an LLM for RAG? Train on Self-Generated Demonstrations