The missing 12 minutes

A root cause analysis question from a product manager interview, set at StreamBox, a fictional video streaming company.

The question

Skills this case tests

A starting metric tree

Watch time per DAU = total minutes watched per day ÷ daily active users

How to approach this case

This is a ratio, so split it before forming any theory: did total minutes fall, did the count of daily users rise, or both? Ask exactly how a daily active user is counted and whether that definition, or the tracking behind it, could have changed, even when the dashboards agree with each other. Then segment by platform, app version, region and content type, and look at the distribution of minutes per user rather than only the average. External events and content releases are worth checking, but test each one against the totals you have. A strong close states clearly what users actually did, says who needs to hear the answer (leadership, investors, the ad sales team) and in what order, and proposes a fix plus a check that would catch this sooner next time.

The full method for root cause analysis questions · A worked example answer

After the mock interview you get scores on five skills, what to fix with quotes from your answers, and the ideal path for this case.