Optimizely claim to have since fixed this. The paper where they introduce the method is here: http://www.kdd.org/kdd2017/papers/view/peeking-at-ab-tests-why-it

Optimizely claim to have since fixed this. The paper where they introduce the method is here: http://www.kdd.org/kdd2017/papers/view/peeking-at-ab-tests-why-it-matters-and-what-to-do-about-it http://www.kdd.org/kdd2017/papers/view/peeking-at-ab-tests-w...