Question 1

What is Retrieval-Augmented Generation (RAG) and why is it preferred over fine-tuning for knowledge tasks?

Accepted Answer

RAG is an "open-book" architecture that allows an AI model to consult specific, external documents before generating a response, rather than relying solely on the information it learned during its initial training. While fine-tuning is effective for changing the "style" or "format" of how a model speaks, it is often a trap for knowledge management because it is expensive, creates a frozen snapshot of information, and can suffer from "catastrophic forgetting." RAG is preferred for factual tasks because it stays up-to-date in seconds as documents change, provides clear source attribution for transparency, and costs significantly less than retraining a model.

Question 2

What is "chunking" and why is it critical to the success of a RAG system?

Accepted Answer

Chunking is the process of dicing up large documents into smaller, searchable pieces of text. It is a strategic balancing act: if chunks are too small, the AI loses the broader context of the information; if they are too large, the specific answer (the "needle") gets lost in irrelevant noise (the "haystack"). In modern production systems, the sweet spot is typically between 300 to 600 tokens with a 10% to 20% overlap. This ensures that thoughts aren't cut in half at the boundaries and that the model receives enough context to understand the nuance of the information retrieved.

Question 3

How does Hybrid Search improve the accuracy of finding specific information?

Accepted Answer

Hybrid Search combines "dense retrieval" (vector search) with "sparse retrieval" (keyword search like BM25). While vector search is excellent at understanding semantic meaning and synonyms—such as linking "locked out" with "password reset"—it can struggle with specific technical jargon, product IDs, or legal codes. Keyword search excels at finding these exact matches. By using both methods and merging the results through techniques like Reciprocal Rank Fusion (RRF), systems can improve retrieval accuracy by 15% to 25% over using vector search alone.

Question 4

What is the "RAG Triad" and how is it used to evaluate AI performance?

Accepted Answer

The RAG Triad is an evaluation framework used to move beyond subjective "vibe checks" and measure the reliability of a system using three specific metrics. First is Context Relevance, which grades the "librarian" by checking if the retrieved chunks are actually useful for the question. Second is Groundedness (or Faithfulness), which ensures the LLM’s answer is derived strictly from the provided documents rather than hallucinations. Third is Answer Relevance, which measures if the final response actually addresses the user's query. This diagnostic clarity allows engineers to identify exactly which part of the pipeline needs improvement.

Question 5

What are the risks of "Embedding Drift" and "Ghost Chunks" in a production environment?

Accepted Answer

Embedding Drift occurs when a model provider updates their embedding model, causing new query vectors to no longer align with the older document vectors stored in a database, which degrades search accuracy. Ghost Chunks refer to outdated information that remains in the search index after a source document has been edited or deleted. To prevent these issues, production systems require "Drift Detection" through daily health checks and "Atomic Updates" to ensure the vector database instantly reflects changes in the company's actual document library.

How RAG works and why it beats fine-tuning

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