Conversion fell from 8.8% to 6.2%. Someone will say roll back signup. Direct went 10% → 11%. Paid went 4% → 5%. More traffic came from paid. The average is not the product.
No clone. The CSV is already on GitHub.
Install one skill
npx skills add patrickjmorris/aftergrid --skill diagnose-change
Installing copies instructions; it does not grant data access. Use /diagnose-change in Claude Code or Cursor, $diagnose-change in Codex. Refresh the agent's skills if it is not visible yet.
Paste this
/diagnose-change Conversion fell from 8.8% to 6.2%. Should we roll
back signup?
Use https://raw.githubusercontent.com/patrickjmorris/aftergrid/main/examples/skills-lab/data/conversion.csv
Reproduce the movement. Separate mix from within-channel change.
Show the calculations. Do not recommend a rollback from the aggregate
alone.
| Period | Channel | Sessions | Signups | Rate |
|---|---|---|---|---|
| Baseline | Direct | 8,000 | 800 | 10% |
| Baseline | Paid | 2,000 | 80 | 4% |
| Current | Direct | 2,000 | 220 | 11% |
| Current | Paid | 8,000 | 400 | 5% |
Four rows. No experiment, no change log. Work within that.
It worked if
The agent recomputes 8.8% and 6.2% from counts, splits mix from within-channel change, and does not treat the aggregate as evidence the signup experience broke. Mix is about −3.6pp; within-channel about +1.0pp. The recommendation is inspect acquisition, not roll back on this table.
Compare with the worked write-up. Then try growth that hid churn and a 50% lift that is not a mandate.
Then use it on your work
Point the same skill at your file. Name the decision owner. State the measurement rules you already know. If the question is still mush, start with grill-question. The full collection:
npx skills add patrickjmorris/aftergrid
Unsure which skill? /ask-aftergrid names one and stops. The workflow guide maps stuck points to skills.
Clone only if you want the rest of the lab on disk:
git clone https://github.com/patrickjmorris/aftergrid.git
cd aftergrid
node examples/skills-lab/verify.mjs
The optional Engine adds typed Findings, retained evidence, and publication controls. Not needed for the four-row case. setup-aftergrid when you want it.