Metrics question
Facebook recently launched a new feed algorithm. As a result, the average session duration dropped by 20%. What would you do?
- Meta
- Metrics
- Hard
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What this question tests
Diagnosing an intentional launch's unintended metric impact, and questioning whether the drop is actually bad.
How to approach it
- Confirm the drop is attributable to the algorithm launch by checking timing and any A/B test data.
- Question whether shorter sessions are actually bad, since more relevant content could mean faster satisfaction.
- Segment the drop by user cohort to see who's most affected.
- Check secondary metrics: session frequency, content quality ratings, and ads served per session.
- Name the real business risk: fewer ad impressions per session hurts revenue.
- Propose a next step: a holdback comparison or a partial rollback for the affected segment.
What a strong answer includes
- Questions the assumption that shorter sessions are automatically bad, tying it to satisfaction and quality metrics.
- Uses the fact that it's a known launch to check existing A/B test data directly rather than guessing.
- Names the real business risk: shorter sessions likely mean fewer ad impressions, the actual guardrail.
- Proposes a clear next step, a holdback comparison or partial rollback, instead of ending on 'investigate more'.
Common mistakes
- Assuming session duration drop is automatically bad without checking satisfaction or quality signals.
- Not using the fact that this was a tested launch to check existing experiment data first.
Likely follow-up questions
- How would you know if shorter sessions actually mean better user satisfaction?
- What would you tell leadership if ad revenue is also down?
More metrics questions
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- 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
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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