# Online Evaluation: A/B Test, Interleaving, CUPED and Statistical Power

> Source: https://sukruyusufkaya.com/en/learn/oneri-sistemleri/online-evaluation-ab-test-interleaving-cuped
> Updated: 2026-05-13T13:29:34.482Z
> Category: Öneri Sistemleri
> Module: Module 3: Evaluation Protocols
**TLDR:** You raised offline NDCG +2% — verify with A/B test before production deploy that user behavior really changes. A/B test sample size math, interleaving (10x more efficient), CUPED variance reduction, and switchback testing.