System Design · Karat · Medium
A video streaming service is introducing a thumbs-up button that lets viewers signal they liked a title. Because this new signal may be fed into the recommendation system, its effects could extend beyond the button itself. Lay out how you would run an A/B test to evaluate this feature. Your plan should cover: the hypothesis being tested and the metrics used to judge it; which users are included in the experiment and how large the sample needs to be; how users are assigned to…