Retrieval baseline from first principles
Build a small search test before adding more retrieval machinery.
Reviewed: 2026-10-03
Source-based teaching example · Fictional data
Narration: Microsoft Mark · locally synthesized

00:00:00.000 — What you will learn

Build a small search test before adding more retrieval machinery.

Visual description:
Build a small search test before adding more retrieval machinery.

00:00:06.625 — The idea

Split source material into pieces you can identify. Check whether search finds the needed pieces. Measure source retrieval separately from whether an answer uses those pieces correctly.

Visual description:
Split source material into pieces you can identify. Check whether search finds the needed pieces. Measure source retrieval separately from whether an answer uses those pieces correctly.

00:00:21.250 — One useful term

Chunk. An identified piece of a source document used in retrieval.

Visual description:
An identified piece of a source document used in retrieval.

00:00:28.875 — A worked example

The exercise searches six made-up policy documents. Exact acronyms and reworded queries may behave differently. Keep the misses and compare rankings against the supplied judgments.

Visual description:
The exercise searches six made-up policy documents. Exact acronyms and reworded queries may behave differently. Keep the misses and compare rankings against the supplied judgments.

00:00:43.667 — Your turn to think

Does finding a relevant passage prove the final answer is supported? Pause and decide before continuing.

Visual description:
Does finding a relevant passage prove the final answer is supported?
Pause the video if you need more time.

00:01:01.292 — Why this answer works

No. Retrieval and answer support need separate checks. The toy scores are not a live-model benchmark.

Visual description:
No. Retrieval and answer support need separate checks. The toy scores are not a live-model benchmark.

00:01:11.375 — Check 1

Keep stable source and chunk IDs.

Visual description:
Keep stable source and chunk IDs.

00:01:16.708 — Check 2

Declare tie-breaking rules.

Visual description:
Declare tie-breaking rules.

00:01:21.583 — Check 3

Report misses rather than hiding them.

Visual description:
Report misses rather than hiding them.

00:01:26.667 — Now try a different case

Open the lesson and try its different practice case. Use every check in the full task. Watching alone does not mark the lesson complete.

Visual description:
Open the lesson
Try the new case
Check and revise
The full task and its requirements are in the linked lesson.