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Oct 25, 2023 · Fundamentals

Mastering Metric Covariance for Accurate A/B Test Analysis

This article explains the statistical foundations of A/B testing, introduces potential outcomes and average treatment effect, defines metric covariance, and presents practical estimation methods—including naive, data‑augmentation, and bucket‑based approaches—along with real‑world performance evaluations and applications such as variance reduction and Bayesian optimization.