Lesson 3.1

Hybrid keyword and vector search

Vector search misses exact identifiers; keyword search misses paraphrase. Running both and fusing the rankings covers each one’s blind spot.

7mAdvanced6.3k students

Overview

What this lesson covers

  • Combine lexical and semantic result sets
  • Fuse rankings rather than concatenating them
  • Fall back to keyword search when embeddings are unavailable

This lesson sits in Retrieval Quality, part of Retrieval-Augmented Generation from Scratch. It assumes what came before it and leads directly into the next lesson in the module.


In this lesson you will:

  • Combine lexical and semantic result sets
  • Fuse rankings rather than concatenating them
  • Fall back to keyword search when embeddings are unavailable
Pro Tip

If embeddings are switched off in your environment, wildcarded keyword matching is the fallback that still works.