Sample size planning
Define minimum detectable effect and confidence level before launch. Underpowered tests cause unstable decisions.
ADVANCED · 11 min read
Statistical Validity in Painted Door Testing
Avoid noisy conclusions with sample-size planning, confidence thresholds, and experiment discipline.
painted door statistical validitysample size validation tests
Variance awareness
Monitor segment variance and channel volatility. Average metrics can hide severe segment-level divergence.
Decision confidence
Build decision thresholds around confidence bands, not point estimates alone.
Frequently asked questions
How long should I wait before deciding?
Until metric stability and sample adequacy criteria are met.
Is significance always required?
For major spend decisions, yes or near-equivalent confidence logic is recommended.