intermediate~3h

Prompting vs. RAG vs. Fine-tuning: A Decision Framework

A 2-axis decision matrix (external knowledge needed vs. behavior adaptation needed) for choosing between prompt engineering, RAG, fine-tuning, or a hybrid — plus a deeper 3-way comparison of full fine-tuning, LoRA, and RAG.

Prompting vs. RAG vs. Fine-tuning — Decision Matrix

Plotted against two axes: how much external knowledge you need, and how much behavior/style adaptation you need.

External knowledge neededBehavior/style adaptation neededRecommended approach
Low / LowLowLowPrompt engineering suffices
High / LowHighLowRAG
Low / HighLowHighFine-tuning
High / HighHighHighHybrid (RAG + Fine-tuning)
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Subtopics
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Exercises
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Projects
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Quiz Qs
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Flashcards
📚 Prerequisites(2)

🎓 Learning objectives

  • Apply the 2-axis decision framework (external knowledge vs. behavior adaptation) to pick the right approach for a new LLM application
  • Explain why RAG changes what a model knows while fine-tuning changes how it behaves
  • Compare full fine-tuning, LoRA, and RAG along the 'what gets modified' and 'what gets stored' dimensions
  • Identify RAG's specific structural limitations (question/answer mismatch, unsuitability for summarization)

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📂 Subtopics