The best RAG strategies focus on improving data quality, smarter retrieval, and better context handling, with key techniques including context-aware chunking, hybrid search (keyword + vector), reranking top results, query expansion/rewriting, and using metadata filtering, often combined in architectures like Agentic RAG or Graph RAG, to reduce hallucinations and boost accuracy for complex, real-world queries. Start simple (chunking, reranking) and progressively add complexity like hybrid search and agents for multi-hop questions. [1, 2, 3, 4]
This video provides a high-level overview of various RAG strategies:
Foundational Strategies (Start Here)
- Context-Aware Chunking: Don't just split by fixed length; use sentence/paragraph boundaries or semantic chunking to keep related ideas together, potentially with overlap (sliding window).
- Reranking: Use a more advanced model to reorder the initial top results from the vector store for better relevance before sending to the LLM.
- Data Cleaning & Metadata: Remove noise, fix errors, and use metadata (dates, types) for effective filtering to narrow down search results. [1, 3, 5, 6, 7, 8]
Intermediate Strategies (Improve Retrieval)
- Hybrid Search: Combine sparse (keyword, BM25) and dense (vector) retrieval to capture both exact terms and semantic meaning.
- Query Expansion/Rewriting: Use the LLM to generate alternative queries or hypothetical documents (HyDE) to cover phrasing gaps.
- Parent Document Retrieval: Retrieve summaries or metadata first, then drill down to full chunks for better context in large documents. [2, 6, 8, 9, 10]
You can learn about sparse, dense, and hybrid retrieval methods in this video:
Advanced Strategies (Complex Use Cases)
- Agentic RAG/Multi-Agent: Employ agents to break down complex, multi-step questions, use multiple tools (like search, graph lookups), and verify answers.
- Graph RAG: Use Knowledge Graphs for structured data and relationships, ideal for complex domains like finance or medicine.
- Context Distillation: Summarize retrieved chunks to fit more relevant info into the LLM's context window.
- Fine-Tuning: Fine-tune embedding models or the LLM itself for specialized domain language or specific output formats (e.g., compliance). [1, 2, 4, 8]
This video explains different RAG architectures in detail:
Key Takeaway
A robust RAG system often combines 3-5 strategies, starting with solid fundamentals (chunking, reranking, data prep) and layering on more advanced techniques (hybrid search, agents) as needed for accuracy and complexity, with the goal of delivering grounded, high-quality answers. [2, 3, 11]
AI responses may include mistakes.
[5] https://www.lettria.com/blogpost/5-rag-chunking-strategies-for-better-retrieval-augmented-generation
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