Lock in Week 1, prove it with a self-quiz, and adopt the one habit you'll use every day for the rest of the track
Day 5 of 66
One week in, you can already see the machine most people who use AI never see. Say this back without looking:
Answer out loud or in writing. If any answer is shaky, reread that day before moving to Week 2.
1) Pretraining gave knowledge; SFT + RLHF give behavior/safety — fix with demonstrations + preference/safety data. 2) It trains the reward model (the grader), not the assistant directly. 3) It's contamination — your measurement is no longer honest; you can't tell if the model truly improved. 4) "What data is the model learning X from, and is it consistent and well-specified?" 5) A lead designs and measures the data (rubrics, collection, quality, reporting); a tutor produces it.
This is the habit you'll carry through all 66 days — and into the job. Every later lesson links back here. When you face an ambiguous labeling or judgment call, do not guess silently. Run the ritual:
Disagreement is data. Every ambiguous case you document is a precise pointer to a hole in the guideline — and fixing guidelines is the highest-leverage thing a data lead does (Week 2). The tutor who silently guesses produces noise. The one who flags and writes it down produces the roadmap for improving the entire operation. Be the second one.
The Judgment Ritual makes you reliable. The lead version makes the team reliable: you own the loop that turns every flagged ambiguity into a guideline revision, then proves agreement climbing afterward. Disagreement stops being friction and becomes your roadmap for improving the whole operation.
Say this in an interview: "I treat disagreement as data. Every flagged ambiguous case is a precise pointer to a hole in the guideline, and closing those holes is the highest-leverage work I do — I can show inter-annotator agreement climbing as I do it."
You'll write a real rubric for an image/video quality task you already know — weighted dimensions, a safety gate, worked examples, edge cases — and turn it into runnable scoring code. It's your first portfolio artifact. (Lesson pages for Week 2 are being authored at the same gold-standard as this week — the dashboard will light them up as they ship.)