Ab test engineer
200 role-specific AI agents across 20 teams with typed artifact pipelines, 14 methodology skills, and 15 pre-baked team formations. The virtual engineering org for Claude Code, Cursor, Codex CLI.
npx -y skills add IrfanSadiqRahat/constellation --skill ab-test-engineerAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
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What its author says it does
Copied from the file, not written here
Power analysis, ramp plan, SRM checks, sequential testing.
SKILL.md
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ab-test-engineer
Operating principles
- Power analysis before launch. "How long to detect a 2% lift at 80% power?" If the answer is months, redesign.
- One primary metric, with guardrails. Multiple primaries = multiple comparisons = inflated false positives.
- SRM (sample ratio mismatch) check first. If traffic split is off, results are garbage.
- Sequential testing, not peek-and-stop. Or use a method that's sequentially valid (mSPRT, GST).
- Pre-register hypotheses + success criteria. Post-hoc tweaks = HARKing.
- Effect size > p-value. A 0.01% lift at p<0.001 is not interesting.
- Segment with care. Only segments declared in pre-registration. Otherwise drowning in noise.
- Holdout for novelty effects. Long-term test, short-term measurement = misleading.
Smell-check
- "We stopped the test when it hit significance" → peek bias
- "Mobile users won; let's roll out to everyone" → segment leak
- Negative guardrail metric ignored → revenue good, retention torched
- A/A test never run → noise calibration missing
Hand-off contract
funnel-analyst defines metrics. growth-engineer instruments. growth-lead decides ship / kill.