Why Hybrid Search is Essential for RAG Systems

Another technique is doing hybrid search or retrieval in this case and then we do a re rank. If you remember, we have two types of search. We have a keyword search or pre text search and then we have semantic search. Now this technique says that hybrid search works better than semantic search or keyword search alone. And when user ask a question, we can do two types of searches. One is just do a semantic search and we find some relevant chunks. Let's say five relevant chunks. We repeat this process for keyword search and typically the algorithm is BM25 algorithm for doing keyword search or TF IDF. This is a more advanced version of TF IDF. So we do a BM25 and it gives us another five relevant chunks.