Metrics question
Facebook's DAU is decreasing 15% per week from the last 3 weeks. Find out why.
- Meta
- Metrics
- Hard
Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.
Start a mock interview on this question · Mock interview from a job description
What this question tests
Tests structured, funnel-based root-cause diagnosis for a severe, sustained engagement decline, a classic 'diagnose a metric drop' interview scenario.
How to approach it
- Confirm scope and rule out measurement error: check whether the 15% weekly decline is logged correctly and consistent across platforms (iOS, Android, web) before assuming a real behavior shift.
- Segment by user cohort: new versus existing users, geography, and age group, since a broad DAU decline often masks a problem concentrated in one segment.
- Check recent product changes: any ranking algorithm updates, a new onboarding flow, or a controversial feature change in the timeframe the decline started.
- Check external factors: a major competitor launch (e.g. TikTok gaining share), a platform policy change (like iOS privacy changes affecting notifications), or a broader industry engagement trend.
- Once isolated, validate the leading hypothesis with a targeted analysis, like comparing the decline rate between users exposed and not exposed to a specific recent change, before proposing a fix.
What a strong answer includes
- Treats a 3-week sustained decline as a serious, systemic signal (not noise) and follows a rigorous, staged diagnostic process rather than jumping to conclusions.
- Considers competitive share loss (TikTok, Reels-adjacent apps) as a real, well-documented external cause for this kind of Facebook-specific decline pattern.
- Uses the given number, three consecutive weeks of 15% decline, to argue this needs urgent, structured investigation, not a minor tweak.
- Proposes a concrete validation method, comparing exposed versus unexposed cohorts, to move from hypothesis to a confirmed root cause.
Common mistakes
- Jumping straight to a fix ('add more notifications') without any diagnostic process to find the actual cause first.
- Ignoring competitive and platform-policy external factors, which are common real causes of sustained DAU decline at this scale.
Likely follow-up questions
- What would be your first action in the first 24 hours of noticing this trend?
- How would you distinguish a competitive share-loss cause from an internal product-change cause?
More metrics questions
- How would you measure the success of Facebook Likes?Meta · Metrics · Medium
- How would you measure improvements made to Facebook messenger?Meta · Metrics · Easy
- Imagine you are the PM in charge of Reactions on Facebook - the new way to interact with posts by using “love”, “haha”, “wow”, “sad”, and “angry” reactions. What would success look like in terms of number of non-like reactions per post at launch and how do you come up with this? Would this number differ by reaction? Why or why not?Meta · Metrics · Hard
- You launched a new signup flow to encourage new users to add more profile information. A/B test results indicate that the % of people that added more information increased by 8%. However, 7 day retention decreased by 2%. What do you do?Google · Metrics · Hard
- Define the metrics for YouTube search.Google · Metrics · Medium
- You are the PM of Instagram app. The MAU has been constant but DAU has declined. What will you do?Meta · Metrics · Medium
More questions from Meta
Learn the skill behind it
Chapters of the AI PM course that teach what this question tests.
- Chapter 9: Prove it paid off: outcomes, economics, and pricing
- Chapter 2: Data fluency: SQL, logs, and reading the truth yourself
- Chapter 14: Get the job: the AI PM interview loop