Applied AI

Course map · S2 Retrieval and RAG · Episode 5 of 16

Search: keyword, vector, hybrid

S2 E5 Explainer · 25 slides · 21 October 2026

  1. Slide 1 of 25, Cover.
  2. Slide 2 of 25, Why it matters.
  3. Slide 3 of 25, Recap.
  4. Slide 4 of 25, Mental model.
  5. Slide 5 of 25, Mental model.
  6. Slide 6 of 25, Worked example.
  7. Slide 7 of 25, Where vector fails.
  8. Slide 8 of 25, Where keyword fails.
  9. Slide 9 of 25, Our question.
  10. Slide 10 of 25, Live, every question.
  11. Slide 11 of 25, Worked example.
  12. Slide 12 of 25, The test.
  13. Slide 13 of 25, The test.
  14. Slide 14 of 25, Finding.
  15. Slide 15 of 25, Where it breaks.
  16. Slide 16 of 25, Finding.
  17. Slide 17 of 25, Lesson 1.
  18. Slide 18 of 25, Lesson 2.
  19. Slide 19 of 25, Built to be checked.
  20. Slide 20 of 25, Where it breaks.
  21. Slide 21 of 25, For engineers.
  22. Slide 22 of 25, For leaders.
  23. Slide 23 of 25, The scoreboard.
  24. Slide 24 of 25, Decision rule.
  25. Slide 25 of 25, Series map.

Lesson notes

Keyword search finds the error codes vector search misses, and vector finds the paraphrases keyword misses, but hybrid search fell short of vector on search, so vector stayed.

Decision rule

Test search on each kind of question your users ask. Keep keyword search for exact codes, and merge rankings only where your tests show it helps.

Ideas in this lesson

  • Cosine similarity
  • Retrieval

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