Why RAG Complexity Should Be Earned

Complexity in Retrieval-Augmented Generation (RAG) systems should be earned by incrementally responding to observed failure modes rather than being adopted by default. Developers should first evaluate the core retrieval subsystem independently to determine if failures are due to poor retrieval or flawed generation. Simpler methods like lexical search (BM25) remain highly competitive, and a strong baseline can be established using hybrid retrieval that combines both lexical and semantic search. Ultimately, a two-stage architecture that uses retrieval for broad recall and a more expensive reranker for precision is an effective and proven approach to improving system performance.