All videosAI systems evaluation2:14

Cases that test the system

Changing a label or grader can change the score without improving the model. Create a new version; do not silently rewrite the earlier result.

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Video summary

The ideas to retain

01

The object is an eval release, not "the dataset"

Represent one evaluation release as:

02

The smallest unit must be auditable

A case should let us resolve at least:

03

Start with a coverage hypothesis

"Representative" does not mean "random" by default.

Key moments

Jump directly to a section

  1. An eval is more than its questions.
  2. Seek coverage. Not just volume.
  3. Change one condition. The decision must change.
  4. Separate families. Not just rows.
  5. Development is not release measurement.
  6. The criterion changed. The evaluation changed.
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00:00 — An eval is more than its questions.

A case needs an input, context and a verifiable expected result.

The rubric and harness determine what is observed and scored.

Version the complete evaluation, not just a list of prompts.

00:22 — Seek coverage. Not just volume.

Start with the tasks and failures that matter.

Cover relevant conditions: permissions, limits and partial failures.

Many easy cases cannot compensate for an untested boundary.

Illustrative example, not a benchmark result.

00:44 — Change one condition. The decision must change.

Suppose returns are allowed through day 30.

Two otherwise identical orders at 29 and 31 days require different decisions.

The pair exposes the shortcut “asks for a return, so approve”.

Illustrative example, not a benchmark result.

01:08 — Separate families. Not just rows.

A paraphrase can leak a development case into the test set.

Group variants by document, entity or seed before splitting.

A duplicate scanner cannot prove the absence of contamination.

Illustrative example, not a benchmark result.

01:30 — Development is not release measurement.

Use dev for tuning and a regression bank for known failures.

Reserve a controlled-access holdout for the release decision.

Repeatedly tuning against that holdout destroys its independence.

01:52 — The criterion changed. The evaluation changed.

Freeze cases, references, rubric, harness and protocol.

Changing a label or grader can change the score without improving the model.

Create a new version; do not silently rewrite the earlier result.

Illustrative example, not a benchmark result.