The lab journal and the experiment log
Be able to document the hypothesis, the setup, the results and the conclusion so that somebody else can repeat it.
Prerequisites
- EExperiment trackingrequired
Intuition
Experiment tracking logs the numbers. The lab journal logs the thinking: why you ran it, what you believed, what you learnt. Without it you repeat the same failed idea in three months.
An entry (10 minutes, straight after the run):
2026-09-20 · #47 — Reranking in RAG The hypothesis: cross-encoder reranking of the top 20 → +5 pp grounding. The setup: run 20260920-1412, the same 200 questions, bge-reranker-base, k=6 after the rerank. The result: the grounding 71 → 74 (±3), the latency +180 ms. The conclusion: a small gain, within the noise. Not worth the latency for the chat; perhaps for a batch. Next: try k=4, and hybrid retrieval first (#48).
The platform's journal (/journal) is built for exactly this and can be linked to lab runs.
Interactive
An exercise: take three of your most recent runs (or made-up ones). Write one entry per run using the template. Then read all three in sequence and answer:
- Which hypothesis was the vaguest? Rewrite it falsifiably.
- Is there a conclusion that is not supported by the result?
- What is the accumulated learning — one sentence that is not in any single entry?
The last is the point of the journal: patterns over time. Search the journal before every new idea («have I tried a lower k before?»).
Mastery means
- Writes journal entries with the hypothesis, the setup, the results and the conclusion
- Links the entries to the runs and the artefacts
- Uses the journal to avoid repeating mistakes
Sign in to do the exercises and build your mastery up.
Sources
- Wikipedia — Laboratory notebook (CC BY-SA 4.0) — CC BY-SA 4.0