Lesson 8 of 8
Final Fine-tuning Experiment
Run a small, measurable experiment with a baseline, held-out evaluation set and a clear rollback decision.
Active reading
Understand the idea
Compare three systems: strong prompting, retrieval if facts are needed, and the fine-tuned candidate. Measure the target behavior and important regressions before deciding whether training was worth it.
Example
Baseline score 78%, LoRA 86%, but safety regression rises from 1% to 6% → do not ship until the regression is fixed.
Practice
Apply this lesson to one real task you already have, then write down how you would verify the result.
Common mistake
Calling the experiment successful because the model “feels more on-brand.”
Key takeaway
Fine-tuning earns production use only when measured gains outweigh measured regressions and cost.