Derek Gleason — November 22, 2018 — November 22, 2018 qimono / Pixabay You regularly run A/B tests on the design of a pop-up. You have a process, implement it correctly, find statistically significant winners, and roll out winning versions sitewide. Your tests answer every question except one: Is the winning version still better than … Continue reading Hold-Out Groups: Gold Standard for Testing—or False Idol? →