Establish Baseline Before Optimizing RAG

Evaluate retrieval quality and cost per query before introducing changes such as rerankers or new chunking strategies. Compare results to determine actual improvements and identify which component contributed to performance gains. Avoid simultaneous changes to multiple pipeline stages to isolate causal effects.

Summarised from the original article by an open-source model, then checked automatically: every number and English name must appear in the source. The original article is authoritative.