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Experiment Designer TEXT

Designs product A/B tests by formulating testable hypotheses, calculating required sample sizes, and prioritizing experiments using ICE scoring. It also provides guidance on interpreting statistical results with practical business context.

5 uses this weeksource alirezarezvanilicence MIT
Quality gate: PASS · better answers · measured 2026-10-23
Blind-judged against the bare model on 2 requests: average lift +3.0 points (specificity, structure, method, fit).
won 2/2, lift +3.0, tokens ×32.25
Security scan: clean · 2026-10-24 · 4 files · ran in sandbox
no network calls, shell tricks, credential access or instruction tampering found in its files.

Try asking

Say it in your own words; the assistant finds this recipe by itself. Examples:

“Jeg skal designe en A/B-test på vores pris-side. Kan du hjælpe mig med at formulere hypotesen og beregne den nødvendige stikprøvestørrelse?”
“Vi har en liste over 5 idéer til nye funktioner. Brug ICE-scoring til at prioritere dem, så vi ved hvilken vi skal bygge først.”
“Min test viste en statistisk signifikant forskel, men effekten er meget lille. Er det værd at rulle ud? Hjælp mig med at vurdere den praktiske betydning.”
“I want to test if changing the CTA button color from blue to green will increase sign-ups. Help me write a proper hypothesis and tell me how many users I need to test this.”
“We have three potential features to build next. Can you score them using the ICE framework based on the impact, confidence, and effort estimates I provide?”
“My A/B test ran for two weeks and the p-value is 0.04, but the confidence interval is very wide. Should I ship the change? Explain the practical significance.”
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Good for

ab-testingexperiment-designhypothesissample-sizestatisticsproduct-managementice-scoringdata-analysis

Not for

Do not use this skill for general data analysis tasks that do not involve controlled experiments, such as cohort analysis or funnel optimization without a test. It is not intended for implementing the technical infrastructure of A/B testing (e.g., writing code for traffic splitting) but rather for the statistical and strategic planning. For pure statistical theory questions unrelated to product decisions, a general statistics skill is more suitable.

Details

When it is the right choice

Use this skill when you need to plan a new product experiment, including defining the hypothesis, primary metrics, and guardrails. It is appropriate for calculating the required sample size to detect a specific effect size or for prioritizing a backlog of potential tests using ICE scores. It is also useful for interpreting the statistical output of a completed experiment to make a go/no-go decision.

The full recipe the assistant reads

Experiment Designer

Design, prioritize, and evaluate product experiments with clear hypotheses and defensible decisions.

When To Use

Use this skill for: - A/B and multivariate experiment planning - Hypothesis writing and success criteria definition - Sample size and minimum detectable effect planning - Experiment prioritization with ICE scoring - Reading statistical output for product decisions

Core Workflow

  1. Write hypothesis in If/Then/Because format
  2. If we change [intervention]
  3. Then [metric] will change by [expected direction/magnitude]
  4. Because [behavioral mechanism]

  5. Define metrics before running test

  6. Primary metric: single decision metric
  7. Guardrail metrics: quality/risk protection
  8. Secondary metrics: diagnostics only

  9. Estimate sample size

  10. Baseline conversion or baseline mean
  11. Minimum detectable effect (MDE)
  12. Significance level (alpha) and power

Use:

python3 scripts/sample_size_calculator.py --baseline-rate 0.12 --mde 0.02 --mde-type absolute
  1. Prioritize experiments with ICE
  2. Impact: potential upside
  3. Confidence: evidence quality
  4. Ease: cost/speed/complexity

ICE Score = (Impact * Confidence * Ease) / 10

  1. Launch with stopping rules
  2. Decide fixed sample size or fixed duration in advance
  3. Avoid repeated peeking without proper method
  4. Monitor guardrails continuously

  5. Interpret results

  6. Statistical significance is not business significance
  7. Compare point estimate + confidence interval to decision threshold
  8. Investigate novelty effects and segment heterogeneity

Hypothesis Quality Checklist

  • [ ] Contains explicit intervention and audience
  • [ ] Specifies measurable metric change
  • [ ] States plausible causal reason
  • [ ] Includes expected minimum effect
  • [ ] Defines failure condition

Common Experiment Pitfalls

  • Underpowered tests leading to false negatives
  • Running too many simultaneous changes without isolation
  • Changing targeting or implementation mid-test
  • Stopping early on random spikes
  • Ignoring sample ratio mismatch and instrumentation drift
  • Declaring success from p-value without effect-size context

Statistical Interpretation Guardrails

  • p-value < alpha indicates evidence against null, not guaranteed truth.
  • Confidence interval crossing zero/no-effect means uncertain directional claim.
  • Wide intervals imply low precision even when significant.
  • Use practical significance thresholds tied to business impact.

See: - references/experiment-playbook.md - references/statistics-reference.md

Tooling

scripts/sample_size_calculator.py

Computes required sample size (per variant and total) from: - baseline rate - MDE (absolute or relative) - significance level (alpha) - statistical power

Example:

python3 scripts/sample_size_calculator.py \
  --baseline-rate 0.10 \
  --mde 0.015 \
  --mde-type absolute \
  --alpha 0.05 \
  --power 0.8
Files in this skill (5)
  • LICENSE
  • SKILL.md
  • references/experiment-playbook.md
  • references/statistics-reference.md
  • scripts/sample_size_calculator.py
Where it comes from

Vendored from alirezarezvani/claude-skills, commit 27cfcd0fb0a4, path product-team/skills/experiment-designer, licence MIT. The upstream licence file ships inside the skill.