Week 12 of 12 · The Lead

Data + QA Plan

Add the dataset plan, the weekly QA and drift alerts, and the calibration plan — then define the eval that will prove the program actually worked

Day 58 ~70 minutes Build Day

Day 58 of 66

The build day that prints your program's spine

You have a scoped problem and a consistent core. Today you build the operating layer: the dataset plan, the weekly quality loop, the calibration plan, and — most important — the eval that will prove the program worked. The Try This box below contains capstone_brief.py; running it prints the spine of your program as a single dictionary where every line points at an artifact you built. Type it in, fill it with your problem's values, and run it. That printout is the skeleton this whole document hangs on.

Why a Build Day this late

By now the code is the easy part — you've written six of these scripts. The point of capstone_brief.py isn't the Python; it's that seeing your entire program collapse into seven labeled lines forces you to notice anything missing. If a line says "TODO," that's the part of your program that isn't real yet.

Part 1 — The dataset plan

Spell out the data you'll collect, in the format a training team consumes, targeted at the failure the program is fixing.

Quantify the expected quality lift

A director will ask "and this gets us to 85% how?" Answer with a chain, not a hope: "The Week 7 analysis shows 60% of adherence failures cluster in multi-object prompts; 1,500 targeted preference pairs on that cluster, at our historical conversion of label-quality to model-quality, projects a ~10–13 point lift — enough to clear 85% with margin." You won't be exactly right. You'll be credible, because you reasoned from the data instead of guessing.

Part 2 — Weekly QA + drift alerts

Bring in your Week 9 audit as the program's heartbeat. Every week, sample labels, compare to gold, compute accuracy with a confidence interval, and fire a drift alert if accuracy drops more than a set threshold.

# qa_loop.py — the weekly heartbeat (Week 9, wired into the program) import math def audit(week, correct, sampled, baseline): p = correct / sampled se = math.sqrt(p * (1 - p) / sampled) # standard error of the rate ci = (round(p - 1.96*se, 3), round(p + 1.96*se, 3)) drift = p < baseline - 0.05 # >5-point drop = alert return {"week": week, "accuracy": round(p, 3), "ci95": ci, "drift_alert": drift} baseline = 0.92 for w, c in [("W1", 92), ("W2", 90), ("W3", 84)]: r = audit(w, c, 100, baseline) flag = " DRIFT — calibrate + audit guideline changes" if r["drift_alert"] else "" print(f"{r['week']}: {r['accuracy']:.0%} 95% CI {r['ci95']}{flag}")

Part 3 — The calibration plan

Attach your Week 10 playbook so the people stay aligned as the program runs. State the cadence, what triggers a session, and how the agreement report drives the agenda.

Part 4 — The eval that proves it worked

This is the part that turns a program into a result. Define, in advance, the evaluation that will answer "did it work?" — before you've seen any outcome, so the answer can't be rationalized after the fact.

Core Theory

Pre-register the verdict

Decide now exactly what reading counts as success and what counts as failure. "We hit 85% gold-set accuracy and a >60% human-eval win-rate against the current model on a held-out set" is a pre-registered verdict. Defining it before the data arrives is what makes an eval honest — it removes your ability to move the goalposts when the number is disappointing.

Two readings, one verdict

The cheap automated reading (gold-set accuracy) runs weekly and shows the trend. The expensive trusted reading (human eval, with the Week 6 position-bias controls) runs at the milestone and is the verdict. If the cheap and expensive readings disagree, the expensive one wins — and the gap is itself a finding to investigate.

The eval is the program's promise

Everything upstream — rubric, pipeline, datasets, QA — exists so this one eval can give an honest answer. When you can say "here is the held-out eval, here is the win-rate I pre-registered, here is the number we hit," you've stopped describing work and started reporting a result. That sentence is what a director remembers.

Your work today

Assemble the operating layer

Run the spine, then fill it

  1. Type in and run capstone_brief.py from the Try This box with your problem's real values. Any line reading "TODO" is a gap — close it.
  2. Write the dataset plan with volumes, format, and the targeted-sampling rationale.
  3. Wire your Week 9 audit and Week 10 calibration in as the weekly loop, with a drift threshold and a trigger.
  4. Pre-register the eval: the exact gold-set accuracy and human-eval win-rate that count as success, written before any result.
The lead move

An annotator hopes the data helps. A lead pre-registers the verdict: states the exact gold-set accuracy and human-eval win-rate that count as success before any result exists, and projects the expected lift by reasoning from the failure-cluster data instead of guessing — credible, not lucky.

Say this in an interview: "I define what counts as success before the data lands, so I can't move the goalposts when the number disappoints. And when a director asks 'how does this get us to 85%,' I answer with a chain from the cluster analysis, not a hope."

Today's Takeaways