Why Is a Reranker Needed in RAG If We Have a Retriever?
Enterprise RAG pipelines have a recall stage and a precision stage. The retriever handles recall. The reranker handles precision. Skipping the reranker, or misplacing security controls around it, is where most accuracy and data exposure problems begin. The retriever’s job is to pull back every document that might be relevant. The reranker’s job is to find, from that candidate set, the documents that actually answer the question.