Weekly active users dropped 12%

The prompt

You are the analyst for a note-taking mobile app. Weekly active users (WAU) have fallen 12% over the last two weeks compared with the two weeks before. The product manager asks you to find out what happened and what to do. How would you approach this?

Extra context you can assume

• WAU = users who open the app and create or edit at least one note in the week.
• No major marketing campaign ended recently, but a new app version was released three weeks ago.
• Data is available by platform, country, app version, acquisition channel and signup cohort.

A strong answer usually covers

• Confirm the metric definition and rule out tracking or data-pipeline problems.
• Check timing: sudden step or gradual slide? Compare with seasonality and holidays.
• Segment: platform, version, country, channel, new vs existing users.
• Decompose WAU into new users, retained users and resurrected users.
• Form hypotheses, rank them by evidence, and say what you would test next.
• End with a recommendation and a way to monitor the fix.

This scenario is fictional and made up for practice.