The Complete Guide to A/B Testing: Sample Size, Duration, and Significance
How to size an A/B test, set the right duration, and judge significance: sample size, MDE, full business cycles, fixed stopping rules, multiple-testing fixes.
Oct 8, 2026
How to size an A/B test, set the right duration, and judge significance: sample size, MDE, full business cycles, fixed stopping rules, multiple-testing fixes.
Search ROI is hard to measure: a three-layer usage-quality-revenue measurement, contribution vs incremental conversion, an ROI formula, and four misjudgments.
Conversion rate down: diagnose first - confirm measurement, break down traffic and funnel, check trust and friction, then pinpoint the page and action.
Funnel analysis gives a conclusion, not a chart: where and why drop-off happens. Learn 3 funnel decisions, the drill-down to find loss, and 3 common pitfalls.
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